Yaman Kouli

Simon Perego

This article introduces a special issue exploring the ways in which diverse political, economic, military, and technical actors in both camps perceived the techno-economic integration and disintegration of Europe during and after the First World War. How to deal with the severing of ties forged over the previous decades? How to go about reestablishing new ties, and with whom? To what extent did wartime reflection and experience relating to these issues shape post-war responses? Research focusing on war aims and peace negotiations shows that in terms of international cooperation and the organization of Europe, these years were neither the polar opposite nor a simple pause of pre-1914 integration. Our aim is to use specific case studies to document how this disintegration unfolded or was contained, as well as to examine why and how new integration was implemented during the war and subsequently called into question when peace returned, before often re-emerging in Europeanist movements and expert networks linked to state foreign policy after Locarno. We will especially focus on transport (rail and road) and patents, two of the most hotly debated issues on both sides, albeit asymmetrically.

European disintegration and integration during the First World War revisited

The level of "internationalization and delicate interdependence of our credit-built finance and industry" is so extensive that any war between European countries would be irrational-attacking the other would amount to hurting oneself. 1 As a result, preparing war in order to gain or protect a state's wealth would be no more than an "optical illusion". 2 Such was the central and performative argument put forward by the British observer Norman Angell around 1910 in the hopes of convincing his fellows from Great Britain and Germany to keep the arms race under control. 3 In the same vein, the American professor of political science Paul Reinsch warned in 1911: "We must realize our interdependence in practical affairs. (…) The incentive to war will become weaker and weaker as the bonds of community between nations increase, such as are provided by communication agencies, by economic and industrial ties, or by scientific cooperation. How intolerably painful will be the ruthless interruption of all such relations and activities!". 4 In his view, the effects of a war would soon be so insufferable that no state would dare initiate one, or alternatively such relations would have to be excluded from the scope of war. Claiming to be part of a "new internationalism"-one that was less sentimental than rational or "practical" 5 -they both argued that the economic integration of Europe, if referred to as such, was the best guarantee of peace. However, war ultimately broke out, and became synonymous with disintegration. Was integration itself the illusion? If not, how should this disjunction between integration and peace be understood? And how was disintegration handled by the actors involved? This introduction to the special issue "European disintegration and integration during the First World War revisited" seeks to answer these three questions. In this special issue, we also raise a fourth and central question, namely the occurrence of integration processes during the war itself. For many years now, economic historians have highlighted the economic integration that characterized Europe at the turn of the nineteenth century, against a backdrop of globalization. They have described a largely liberalized market in which raw materials, goods, and capital circulated intensively. 6 They have shown that this first level of integration was complemented by a second, one where ownership of the means of production was internationalized, notably through the development of multinational companies, and where workers were mobile. 7 In the absence of an economic and monetary union, which marks the third and final stage in theories of economic integration, these historians have nonetheless underscored the experience of the Latin Monetary Union, and have described the decentralized mechanics behind the establishment of a gold standard, whose benefits for trade offset the rising customs 1 Angell, Norman, Europe's Optical Illusion (London: Simpkin, Marshall, Hamilton, Kent & co, 1909), p. 26.

2 Idem. 3 A writer, Sir Norman Angell (1872-1967) later became a British Politician. In 1933, he was awarded the Nobel Peace Prize. 4 Reinsch, Paul, Public International Unions: their Work and Organization. A Study in International Administrative Law, Boston and London, Ginn and Company, 1911, p. 7.

5 Idem, p. 1-2. 6 See the pioneering book by Pollard, Sidney, The Integration of the European Economy Since 1815, London, George Allen & Unwin, 1981. See also : Craig, Lee A. and Fischer, Douglas, The Integration of the European Economy, 1850-1913, Basingstoke, Macmillan, 1997. 7 Strikwerda, Carl, 'The Troubled Origins of European Economic Integration: International Iron and Steel and Labour Migration in the Era of World War I', American Historical Review, xcviii (1993), 1106 -42. tariffs that emerged from the 1870s onwards. 8 More recently, they have taken a closer look at the international conventions and organizations that, beginning in the 1860s, established the technical and legal rules governing the transnational communication and transport infrastructures, which made this traffic possible in Europe and beyond. [START_REF] Kaiser | Writing the Rules for Europe[END_REF] For all these reasons, and because European societies were at the heart of these processes, it seems appropriate to speak of Europe's techno-economic integration as part of pre-war globalization. [START_REF] Kouli | Politics and Policies of European Economic Integration[END_REF] From an economic point of view, the recent reconstruction of sophisticated quantitative indices demonstrates that this integration was quite profound, but neither linear nor homogeneous. [START_REF] Kouli | Measuring European Economic Integration 1880-1913 -A New Approach[END_REF] The integration index, as calculated from the 1880s to the 1910s, varies in time and space. The average level reached in the 1880s represented a high point, after which the share of trade with non-European countries (the United States, of course, but also colonies and protectorates) increased, with the average index for European integration decreasing as a result. Nevertheless, in absolute terms, intra-European trade increased significantly over the period, and depending on the country represented between 32% (United Kingdom, 1880; 1913: 33%) and 88% (Switzerland, 1880; 1913: 74%) of total trade in relative terms. The variation from one country to another is therefore relatively marked. According to this index, Portugal and the UK were among the least integrated countries in the European market over the period. Conversely, France and the Netherlands were the most integrated. In short, European countries were well integrated within both European and global markets, albeit to varying degrees. This European techno-economic integration was not synonymous with the disappearance of states and nations. On the contrary, state-building, the nationalization of societies, European integration, and globalization had evolved in a simultaneous-and even connected-fashion. According to Jörn Leonhard, this explains why Europe was characterized by common developments across the continent, starting with the strengthening of the state as the entity responsible for citizens, administration, and daily life. Over the course of Europe's long nineteenth century, the nation, the nation-state, and nationalism became central points of reference for the affirmation of the state externally, and for political order and social organization internally. [START_REF] Leonhard | Die Büchse der Pandora: Geschichte des Ersten Weltkriegs[END_REF] Leonhard implicitly confirms Sebastian Conrad's argument. The historian argues that the German nation in particular was shaped by the globalization that followed the 1880s. According to this approach, sharp national distinctions were a result of worldwide entanglements and the ambition to construct an individual, distinguishable regime. More generally, he emphasizes that globalization and the knowledge on the development in other countries did not lead to homogenization, but to comparability, which in turn affected national regulations. 13 Intergovernmental cooperation as organized at the time, sector by sector, reflected this complex process, which in the end did not erase borders, but co-produced them. The effects of borders were increasingly the result of concerted action. Except in rare cases (such as navigation on the Rhine) [START_REF] Thiemeyer | Supranationalität im 19. Jahrhundert? Das Beispiel der Zentralkommission für die Rheinschifffahrt und des Octroivertrages 1804-1851[END_REF] , there was no question of pooling sovereignty. The cause of international arbitration represented the cutting edge of an essentially administrative form of governmental internationalism [START_REF] Herren: Herren | Governmental Internationalism and the Beginning of a New World Order in the Late Nineteenth Century[END_REF] , while in diplomatic terms, the Concert of Europe was limited to occasional meetings between major powers on subjects that had garnered initial and unanimous agreement for inclusion in the agenda. [START_REF]European economic integration had produced no agency stronger than the Concert, nor much demand for one[END_REF] On the other hand, European integration-which was certainly not referred to as such, but which was perceived and understood by some contemporaries as a set of technical-economic interdependencies determined by and determining power relations-remained largely "hidden" for populations, who apprehended reality primarily through the prism of the small homeland, the state, and/or the nation. [START_REF] Misa | Introduction. Inventing Europe. Technology and the hidden integration of Europe[END_REF] Above all, it was not a long-term political objective in itself, instead deriving from a series of private initiatives and political decisions that were linked but not coordinated. [START_REF] Strikwerda | Response to "Economic Integration and the European International System in the Era of World War I[END_REF] Finally, it was accompanied by cultural hierarchies and multiple, long-lasting internal divisions. [START_REF] Chaubet | Histoire intellectuelle de l'Europe[END_REF] To take just one example, when Spain and Russia deliberately chose a different rail gauge from the one used in the rest of Europe, it was not just their immediate neighbours they were refusing to link up with-even if that was their priority-but a wider transnational traffic area. Under these conditions, integration and cooperation could not automatically preserve peace, all while keeping in mind that war was not inevitable. Angell himself was well aware of that, and advocated for a transnational reform movement to curb the arms race, while Reinsch made a plea for states to prioritize cooperation over competition. 20 Growing diplomatic tensions led to a weakening of ties in the early 1910s, particularly in the financial sector. In 1913, for example, the French bank Société Générale resigned itself to ceasing short-term investments in Germany, as well as repatriating funds and cutting ties with its Austrian partners in Central Europe and the Balkans. 21 It was against this backdrop that the political elites brought to power by the ruling classes-Christopher Clark's somnambulists, seen by Georges-Henri Soutou as tightrope walkers 22 -plunged European societies into a long and total industrial war. This conjunction of economic integration and political cataclysm has naturally given rise to a multitude of interpretations. 23 All of them, however, agree in describing the outbreak of war as the end of integration. In fact, what had initially seemed to unite was now used to aggress or repel. Infrastructure became crucial for transporting troops and equipment, or for remote control and command, while the market was also transformed into a weapon via the blockade. 24 Today, the First World War is commonly seen as a blow to the age-old process of techno-economic integration, followed by a second one twenty years later. This is so much so the case that the period between 1914 and 1950 is presented as one of "disintegration". 25 Moreover, the short twentieth century from 1914 to 1989 is seen as an uncertain struggle between disintegration and reintegration, ultimately won by the second with the fall of the Iron Curtain and the end of the USSR.26

Questioning (dis)integration during the war

The historiography has questioned the decisive break represented by the Second World War by bringing greater nuance to the continuities and ruptures at work from the 1920s to the 1950s in terms of projects and practices, as well as institutional and personal trajectories relating to the organization and government of Europe27 , including recently in the context of Nazi Germany and Fascist Italy28 , notably with respect to technical cooperation. 29 However, this effort has only been sketched out for the First World War. 30 The reversed order of priority between the First and Second World Wars is easy to understand. It was after the Second World War, and not the First, that the policies of European construction began, from which the European Union and other European institutions of today directly descended. As for the First World War, it is precisely its global character that has been the focus of most recent studies, as a counterpoint to a Eurocentric approach. As Laurence Badel has argued, this decentralization should not obscure, however, the fact that Europe was the epicentre of the conflict, and that it remained central to the peace negotiated in 1919. 31 It is also clear that in this Europe, the years of war between 1914 and 1918-or 1923 to adopt a broader chronology in line with the intra-and international armed conflicts that survived the armistice on the Western Front 32 -were neither the polar opposite nor a simple pause of pre-1914 integration. A pause would mean that nothing would have happened, that everything would simply have been suspended, pending a return to normality. Of course that is not what occurred. Cutting established links, to put it bluntly, involved decisions and actions on the ground, which generated controversy and circumvention. As for the return to "normal", it implied a great deal of effort, even during the war itself, and appeared to be highly ambiguous most of the time. 33 A polar opposite, on the other hand, would mean that the war was merely the flip side of integration, marked exclusively by severed ties and disintegration. Patrick Fridenson and Pierre-Cyrille Hautcoeur conclude their reflection on the role of war in the main processes that have marked contemporary Europe with the following thought: "The First World War remains without doubt, in its multiple effects, the most important event of the twentieth century, at least on a European scale". 34 Curiously, they do not mention economic integration among these processes, but they rightly point out that "the coordination organized" by public authorities in conjunction with business during the war "was extended to the international level in each of the two camps, relying in particular on new experts in international crisis management (food, raw materials, maritime transport)". 35 They also point to certain post-war extensions in this area. This was what led David Stevenson to write, in a seminal article published in 2012, that "the wartime experience helped to shape later integration initiatives during the interwar years and even beyond". Let us return to this article in detail. Synthesizing research on the war aims and economic diplomacy of the belligerents, it first shows that prospects for Central European economic association or union-which had been debated in Germany in an informal and limited manner before the war in the face of emerging American powerhardly disappeared, and instead suddenly took on substance with the conflict. 37 They became a tactical tool deemed important by many political leaders for ensuring Germany's continental domination via networks and exchanges. From August 1914 to the final months of the war, German leaders discussed uniting Belgium with the Reich on a long-term basis, without annexing it in its entirety. Under these plans, the Belgian state would retain a semblance of existence, but would be vassalized under skilfully imposed railway, fiscal, monetary, and customs policy. The same applied to the Polish and Baltic lands conquered from Russia. But the latter were particularly important in terms of relations with the Austro-Hungarian ally. Following the conquest of these territories in the summer of 1915, Chancellor Bethmann-Hollweg himself, who had long been very hesitant on the subject, officially proposed, in Vienna in November 1915, to strengthen relations with Austria-Hungary, notably through the establishment of an economic union or at least a customs policy, thereby creating a bloc to which subjugated, neutral, and perhaps even enemy states (once defeated) could join. The topic of an integrated Mitteleuropa was very much in the public eye at the time. 38 In return, Austria-Hungary would have received most of Polish lands. Internal opposition toward giving priority to European markets at the expense of global outlets-and the prejudices of an Austro-Hungarian Dual Monarchy with its complex governance along with the hazards of war-prevented the discussions between experts from leading to an agreement. In the spring of 1916, Germany's Polish policy changed, with the aim of turning Poland into a controlled buffer state through expanded infrastructure connections and a customs association. However, developments on the various fronts and changes in political personnel made these balances highly unstable. Beginning in the summer of 1917, Germany's Polish policy changed again. The renewed negotiations with Austria-Hungary once again turned Poland into a bargaining chip: the country would be entrusted to the Dual Monarchy, but plans for its techno-economic integration with Germany were not abandoned. The project for economic union between the two Empires remained on the table. Revised both upwards-with free internal trade, a common external customs policy, and the pooling of customs revenues, but without the creation of common institutions-as well as downwardswith simple tariff reduction agreements and trade facilitation by harmonising legal and regulatory frameworks-it was negotiated right up to the very last months of the war, but never came to fruition. Stevenson's article then points out that in return, Allied countries led by France sought to strengthen their ties in wartime and to maintain them in peacetime, with a view to weakening enemy nations and avoiding long-term dependence on them. In fact, France became more closely linked than ever to the English and American markets, which, according to Stéphane Becuwe and Bertrand Blancheton, supplied 60% of its 38 The idea of a "Mitteleuropa" already existed during the 19 th century, when European economists wondered how Europe's position could be ensured in a world where players like the Russian Empire and the USA emerged; see Kouli, Yaman, From a "Ring of Friends" to a "Ring of Fire" -The Failed Dream of Middle Europe, in: Studia Europejskie. Studies in European Affairs 22.4 (2018), S. 97-107.

total imports over the period. 39 But France did not exert the same ascendancy in its block as Germany did in its own. The various projects that emerged remained largely unproductive. The resolutions of the economic conference held in Paris in June 1916 provided for reinforcing the blockade during the conflict, as well as post-conflict discriminatory measures in favour of invaded countries (priority access during reconstruction to certain resources and equipment) and against the Central Powers (exclusion from the most-favoured-nation clause, joint efforts to reduce dependence on their production). They were only ratified by France and Great Britain. The latter repented when the United States entered the war the following year, and remained opposed to any extension of economic warfare in peacetime. Despite being limited to the control of raw materials, these measures did not survive the end of the conflict. While an original experiment in international administration was born-through bodies such as the International Supply Commission, the Executive Commission for Wheat and in late 1917 the Allied Maritime Council-the proposals put forward upon the return of peace by the French Minister of Trade Etienne Clémentel to perpetuate this cooperation between the Allies failed to materialize. [START_REF] Reinalda | Routledge History of International Organizations: From 1815 to the Present Day[END_REF] With the victories on the Western Front, the Minister's advisor, Henri Hauser, began pushing again in the summer of 1918 for a broader "Westeuropa" project, an economic union in response to the Germanic Mitteleuropa. [START_REF] Hauser | Henri Hauser et la Première Guerre mondiale[END_REF] The French government approached the U.S. government, but the armistice changed the situation, convincing the U.S. government to pursue a policy of international commercial non-discrimination and non-interference in U.S. trade relations. Despite the views of the "London Group" (the informal network of state representatives), such Executive Committees were abolished at the end of the conflict, out of political concern for a return to the previous state, in which sovereignty was not shared. [START_REF] Decorzant Yann | La Société des Nations et l'apparition d'un nouveau réseau d'expertise économique et financière (1914-1923)[END_REF] However, the idea of economic and financial cooperation did not disappear. The financial crisis led private financial players to call for concerted and coordinated intervention by states. The League of Nations was all the more fertile ground for this, as the men of the London Group now held key positions within it. In 1920, the Genevabased institution organized a conference, and set up a new structure to address these issues. The same kind of (dis)continuity was present in the Interallied Sanitary Commission, which remained little-known until Anne Rasmussen's work on the topic. [START_REF] Rasmussen | Documenter la santé en guerre : l'Internationale sanitaire interalliée, 1915-1919[END_REF] Set up in 1916, its aim was to form a common front against the diseases whose spread was facilitated by the war, and which could determine the outcome of the conflict. The Commission moved into the premises of the Office International d'Hygiène Publique (OIHP), created in 1907 in Paris. It expanded exchanges between scientists and helped create a new form of transnational disease regulation, which would be directly implemented in the aftermath of the war when the OIHP resumed its activities, as well as in the Hygiene Committee of the League of Nations upon its creation somewhat later. "Between 1914 and 1918 both sides had pioneered new arrangements for international co-operation" 44 , concluded Stevenson, for whom these reflections and experiences fed into institutionalized cooperation and Europeanist movements in the ensuing years. In this sense, the reflections and movements in favour of European unification, whether through the market or cartels, did not develop in the 1920s simply to ward off war, American domination, and the limitations of the League of Nations; they were broadly driven by the experiments and reflections initiated during the conflict, even if these had national or even nationalistic interests with hegemonic aims, and remained for the most part without a future immediately after the armistice. This special issue raises the question of how "integration" was understood during the war and its aftermath by a diverse set of actors, primarily political and economic, but of course military and technical as well. How should the severing of ties forged in previous decades be handled? Why, how, and with whom to re-establish new ties? To what extent did reflections and experiences on these issues during the war influence the responses to them afterwards? While the background is well known thanks to the research cited above, our aim is to document, on the basis of specific case studies, how disintegration unfolded and was contained where necessary, as well as why and how new integration was conceived and implemented during the war, and subsequently called into question when peace returned, before often re-emerging in Europeanist movements and expert networks linked to state foreign policy after Locarno. 45 We will pay special attention to transport (rail and road) and patents, two of the most widely discussed issues on both sides, albeit asymmetrically. The Central Powers were primarily concerned with rail transport in order to overcome the challenge of strengthening overland trade, while the Allies were more concerned with maritime transport and patents, which in the case of the latter opened up the question of controlling and marketing technical innovation, a field in which German interests were particularly active before the war. Taking into account variations across the spaces, actors, and fields concerned enables us to provide nuanced answers to the questions surrounding instances of disintegration and integration, in line with the historiographical approach developed by a "transnational generation" of researchers attentive to experiences shared across or within national borders. 46 A continent "disintegrated" by war "[…] the links between the different parts of Europe, so painstakingly established over the years, were ruthlessly broken", writes historian Sidney Pollard in his classic work on the economic integration of Europe since 1815. 47 The disintegration of transnational socio-technical systems under the effect of the exogenous shock represented by this 44 Stevenson, art. cit, p. 857. 45 Schot and Schipper suggest that the disappointment of experts with the inability to safeguard peace in 1914 convinced them of the need to replace or at least to supplement the power of diplomats with that of specialists; ref. 46 first total war is a historical phenomenon in its own right, with its own causes, consequences and correlations. But what concepts should be used to describe and understand it? It would be useful to reflect on the disconnection of infrastructures, the disruption of supply and value chains, the disappearance or dormancy of the joint institutions where formal and informal rules were negotiated, the shrinking networks of those who led them, and conversely on the increasing visibility, as a result of the crisis, of a hitherto concealed integration. On 11 July 1914, less than three weeks before the outbreak of hostilities, the French, German, and Austrian telephone administrations reached an agreement to set up a direct line between Paris and Vienna via the German network. 48 Of course, the war interrupted this instance of administrative solidarity and technical connection. Crossborder communications between belligerents were cut off, and the meetings scheduled for the following months were gradually postponed. The railway situation was a testament both to the integration that had prevailed and the cutting of ties due to the conflict. Although the military successfully prevented the building of a line connecting the French and German parts of Lorraine, which had been split in two by the demarcation of the border after 1871, the networks of the two countries were sufficiently linked such that almost one in seven French railcars was in enemy territory when war was declared, resulting in 54,000 being lost in the process. Conversely, German, Austrian, and Belgian railcars were seized on French territory. The balance, however, was a loss of 37,000 railcars, which would prove to be a serious blow to the French war effort. With transport and communication lines cut or targeted, and trade with enemy powers banned (decree of 27 September 1914 in France), the flow of people, goods, and capital collapsed. International trade contracted sharply. For all countries, there were significant disruptions to transnational supply chains, exacerbated by blockades. Depending on the situation, this led to shortages as well as adaptation or replacement strategies, with unforeseen consequences. The case of sugar is instructive. In 1902, the main producing countries, including Great Britain, France, and Germany, signed a convention in Brussels with the dual aim of avoiding overproduction and liberalising world trade. 49 At the time, this was a unique example of international economic regulation. 50 The war broke this pact. Due to a lack of production, France practically disappeared from the market. In Germany, poor harvests and the difficulty of obtaining supplies from abroad led the authorities to resort to other products to obtain alcohol, which was increasingly needed for the manufacture of fuel and explosives: potatoes were "mobilised". But the 1916 harvest was half that of 1915. This combination of factors led to dramatic food shortages, social unrest, deaths (estimated at between 400,000 and 700,000) and a new relationship between the state and its citizens. 51 48 Léonard Laborie, L'Europe mise en réseaux. La France et la coopération internationale dans les postes et les télécommunications (années 1850-années 1950), Bruxelles, Peter Lang, 2010, p. 201. 49 Abelshauser, Werner, 'A globalização do mercado do açúcar no século XIX e suas conseqüências para a economia e o custo de vida na Europa', in Ulrich W. Gmünder (ed.), A Rapadura e o Fusca: Cana, Cultura, Sociedade (Salvador: Goethe-Institut, 2009), pp. 148-59.

50 Jamie Martin, The Meddlers. Sovereignty, Empire, and the Birth of Global Economic Governance (Harvard, Harvard University Press, 2022), p. 271. 51 Belinda J. Davis, Home Fires Burning. Food, Politics, and Everyday Life in World War I Berlin (Chapel Hill, University of North Carolina Press, 2000), 349 p. For a Europe-wide view: Proctor, Tammy M., « Les politiques de la pomme de terre pendant la Grande Guerre en Europe », in Williot, Jean-Pierre, de Ferrière Le Vayer, Marc (dir.), La Pomme de terre : De la Renaissance au XXIe siècle (Tours : Presses universitaires François-Rabelais, 2011). Online: <http://books.openedition.org/pufr/21630>. The article by Nicolas Chachereau and Gabriel Galvez-Béhar in this issue shows that in the field of patents, the number of applications fell, especially from foreigners. States decided to free themselves of the convention that bound them, without formally denouncing it. Faced with the imperatives of total war, the regulations in force were suspended. It was no longer possible for a German to apply for a patent in France, and vice versa (although this was much rarer). Above all, countries infringed international law by no longer recognising the value of patents that had already been granted, with some being cancelled, and others seized for exploitation by nationals of the country concerned. Jacek Jędryszczak's contribution reminds us that the German, Austrian, and Russian rail networks were little or not at all interconnected before the war. This lack of connection was most present in the Polish and Baltic areas, which were divided across the three empires. Although industrial circles in German Upper Silesia were keen to see the creation of cross-border lines to the east, which would have enabled them to import raw materials from Ukraine, the German military paid no attention to this before the outbreak of hostilities. The situation changed with the outbreak of war, and even more so in 1915 when the retreating Russian army adopted a scorched-earth policy. The German army now needed to transport large numbers of men and equipment, and its fundamental aim was to control the territory. This strategic imperative came up against hesitations about priorities and differences of opinion with civilians. The railway network inherited by the new Poland was very much affected by these uncertainties. Michal Ďurčo examines the break-up of the Austro-Hungarian Empire and the construction of the Czechoslovak state at ground level, through the prism of roads. He points out that the eastern part of this state, what is present-day Slovakia, was the scene until August 1919 of discontinuous but violent clashes between Czechoslovak authorities and Hungarian forces after the armistice of November 1918. The transport network was both severely tested and confirmed in its strategic role for the new state. Measuring and describing the disintegration is not, however, the sole aim of this special issue, which also seeks to provide a counterpoint via the dynamics of integration at work during the war, and how they were prolonged or interrupted afterwards, particularly in Central and Eastern Europe.

A continent home to antagonistic projects for techno-economic integration with political aims

In the highly uncertain environment of war, those involved knew how to circumvent laws and dead-ends in order to at least partially re-establish interrupted contacts. Switzerland served as an ideal trading platform. French companies sent their fabrics, perfumes, and pharmaceutical products by parcel post to local Swiss retailers, where the end customers from the central empires would purchase them. 52 In September 1917 alone, more than 14,000 parcels of cotton and wool bound for Switzerland were seized in France. Sometimes, the routes were even more complex. Thousands of parcels originating in France and destined for German companies arrived in Chile via Switzerland or Scandinavia. Neutral states were generally tolerant and allowed goods to circulate; this was complicated but all the same possible. However, these flows were marginal compared with pre-war volumes. The situation sparked integration projects within each camp, whether to secure supplies and outlets in the short term, or to build a transnational controlled space in the medium or long term. The conflict exerted pressure to integrate through unprecedented logistical challenges, giving rise to projects, debates, and tensions. As Phil Johnstone and Caitriona McLeish have summarized: "It seems counter-intuitive at first, given the most obvious consequence of war is division between nations. Yet, to meet the challenges of maintaining the delivery of sociotechnical systems for the functions of war, certain countries were brought closer together in order to deal with various logistical challenges. WWI intensified the rule to coordinate internationally". [START_REF] Johnstone | World wars and sociotechnical change in energy, food, and transport: A deep transitions perspective[END_REF] As we have seen, it was on the side of the Central Powers that thinking began the earliest. The war did not eliminate the circulation of foreign experts, but it limited their horizons to the space of allied countries, and placed them under the ever more attentive control of state authorities-at with respect to the Ottoman Empire. 54 Plans for organising a Mitteleuropa of variable geometry always gave pride of place to the development of connected infrastructure, railways in particular. It was in Central and Eastern Europe that the clearest changes occurred. There is little historiography on this subject, and this special issue uses two examples to begin filling the gap. If we consider the case of Poland, a country reborn in the aftermath of the war, there is nothing obvious about the notions of integration associated with the pre-war period, and of disintegration associated with the war. Before the war, the territories that would later form Poland were a border area marked by cuts between the German and Russian rail networks. With the outbreak of war, the situation changed. There was destruction, but the military occupation and hegemonic German plans for integration without annexation meant that in November 1918, the network was better integrated across this area than before the war, because it had been brought up to European standards. As for the post-war period, at a time when nationalist tensions between Germany and Poland led people to believe that the break would be total, an agreement that was particularly favourable to trade allowed people and goods from Germany to transit via the Danzig corridor to East Prussia via train. Journey times between Berlin and Königsberg returned to pre-war levels in 1925, and fell steadily thereafter. All means of transport, not just rail, were concerned. While this also applies to the development of civil aviation in the wake of military aviation, Michal Ďurčo's article focuses on roads. This ancient infrastructure offers an even clearer view of the shift from one political configuration to another. While the destruction of the Austrian and Ottoman empires led to the appearance of thousands of kilometres of new borders, with profoundly destabilising effects on the economic fabric [START_REF] Heinemeyer | The impact of new borders on trade: World War I and the economic disintegration of Central Europe[END_REF] , the successor states immediately embarked on proactive infrastructure-building policies in accordance with their national vision and international alliances. Disintegration was almost immediately followed by new integration. As soon as the Austro-Hungarian Empire was dissolved, roads were built in Slovakia to strengthen the links between Czech and Slovak lands, with the dual aim of providing military security and building the new Czechoslovak state. Running east-west, they run perpendicular to those inherited from the Kingdom of Hungary, which pointed south towards Budapest. Links were being broken, others were being created. Later, the opportunity to build new roads reserved for cars (motorways) would lead certain actors to reproduce this pattern, while placing it in a European perspective: a motorway linking the country's two poles could also be a founding link in an axis between Eastern and Western Europe. The integrating pressure of war also existed on the side of the Allied and associated powers. Transport infrastructure was clearly affected, rail in particular. The idea for a tunnel under the English Channel resurfaced in 1916. [START_REF] Grayson | The British Government and the Channel Tunnel, 1919-39[END_REF] However, because the British War Office believed that such a structure would make the country more vulnerable, the project was postponed. After being assured by France and the United Kingdom that they could set foot in Albania after the victory, the Italians relaunched the project for a trans-Balkan railway line. [START_REF] Sette | L'échec du projet italien de la ligne ferroviaire transbalkanique « Rome-Valona-Constantinople[END_REF] Work began with the help of soldiers and prisoners of war. However, the return of peace brought work to a halt. At the same time, the British and Americans delivered tens of thousands of locomotives and railcars to the French in order to compensate for enemy seizures and destruction. This equipment remained in circulation in the French network after the war. Telecommunications infrastructure shares a fairly similar history. [START_REF] John | Circuits of Victory': how the First World War shaped the political economy of the telephone in the United States and France[END_REF] The U.S. Signal Corps was one of the first American contingents to land in Great Britain and France in the summer of 1917. It reinforced the existing telecommunication lines between the two countries and built a network on the continent from scratch using state-of-the-art equipment. This proved to be crucial for efficiently transporting much-needed men, equipment, and supplies from the Atlantic ports to the front. At the end of the war, the U.S. Signal Corps left behind its lines and a huge stockpile of supplies. The French network was now permanently linked to American industry, and the French administration that ran it could, with British support, embark on a project to strengthen cooperation in Europe, one that would improve international links while containing powerful German interests. The German administration and industry experimented with long-distance links with their Austrian and Ottoman allies during the war. On the strength of these achievements, they decided in the early 1920s to expand the national network in the hopes of keeping Germany at the centre of the map for European flows. The need for an agreement to restore and develop transcontinental telephone exchanges led to the reactivation of pre-war links between experts on both sides, who now carried with them the legacy of the conflict. These were the origins of the International Consultative Committee for Long Distance Telephony in Europe, which was initially set up without the Germans (1923), before opening up to them the following year. This organisation was an agent of integration, and was largely forged in and by the experience of war. [START_REF] Henrich-Franke | Technology Taking Over Diplomacy? The 'Comité Consultatif International (for) Fernschreiben' (CCIF) and Its Relationship to the ITU in the Early History of Telephone Standardization, 1923-1947[END_REF] The article by Nicolas Chachereau and Gabriel Galvez-Béhar completes this overview by touching on the little-known subject of wartime cooperation with respect to the regulation of industrial property. The first exchanges took place at the Allied Economic Conference in Paris in June 1916. While the negotiators envisaged a profound break with the pre-war international economic system, recommending the creation of a longterm economic alliance that would marginalise German industrial and financial power in the field of trade, they simultaneously considered the achievement of objectives that had hitherto remained out of reach, or that were discussed only by a few isolated supporters. The increasing interventionism of public authorities in the economy made this possible, opening up the possibility of integration that was less market-oriented, more top-down and government-led. This was particularly true in the sensitive area of patents, where there was talk of more thoroughly unifying the legislation of Allied countries. The initiative was taken up again in the immediate post-war period by France through the project for an Interallied Patent Office, albeit in vain, as British reservations scuttled the idea. The fact remains that none of the member states of the Paris Union (1883) had left the organisation, and consequently, despite considerable uncertainty, the convention that had given rise to it remained in force, at least in theory. A study of its sister organisation, the Berne Union on Intellectual Property, clearly shows that the international office in Berne was sheltered by Swiss neutrality, and that national professional associations (of writers, publishers, and booksellers) worked hard during the war to ensure that this was the case. 60 In practice, as in many other sectors organised through administrative unions, legal ties were closed at worst, but not completely severed. Under these conditions, the reorganisation plans put forward by the victors failed to make any headway, especially those of the French government, which sought a more directly political approach to international regulation. The resilience of the existing structure enabled the coalition of players that had secured it to return to the pre-war order, sometimes bypassing the provisions of peace treaties. 61 However, by shifting a number of parameters to foster greater capacity of action for public authorities, an expanded mobilisation of society, and enhanced supply security (energy, food, transport, and communications capacity), the war changed the relationship between states, in addition to as well as their techno-economic environment. A return to the status quo ante therefore involved erasing the impact of the war. 62 The disintegration of Europe as a result of war is a complex phenomenon, which calls for a nuanced approach. It should not obscure the integration that was underway or under discussion within the framework of military alliances. Even though most of the projects developed during the war failed due to a lack of agreement between the parties involved, and the plans for European integration subsequently had the primary objective of avoiding a repeat of the horror and destruction of the war, the war cannot

  36 30 For a broader reflection on the two World Wars and the transnationalisation of European societies see Barbara Lambauer, Christian Wenkel (Hg.), "Entstehung und Entwicklung transnationaler Kommunikationsräume in Europa zu Kriegszeiten, 1914-1945", Comparativ, 2018/1. relations internationales », in Hautcoeur, Pierre-Cyrille et al. (dir.), La rupture ? La Grande Guerre, l'Europe et le XXe siècle (Paris: IGPDE, 2021). Disponible sur Internet : <http://books.openedition.org/igpde/15187>. DOI : https://doi.org/10.4000/books.igpde.15187. 32 Gerwarth, Robert, and Erez Manela, eds. Empires at War 1911-1923. Oxford: Oxford University Press, 2014. 33 See the excellent study of Isabella Löhr, « Le droit d'auteur et la Première Guerre mondiale : un exemple de coopération transnationale européenne », Le Mouvement social, 2013/3, n°244, p. 67-80 and from the same author: "Transnational Cooperation in Wartime: The International Protection of Intellectual Property Rights during the First World War", in C. Dejung & N. Petersson (eds.), The Foundations of Worldwide Economic Integration: Power, Institutions, and Global Markets, 1850-1930 (Cambridge: Cambridge University Press, 2013), pp. 205-227. 34 Hautcoeur, Pierre-Cyrille et Fridenson, Patrick, « Retour vers le futur de la Grande Guerre : pourquoi ? » in Hautcoeur, Pierre-Cyrille et al. (dir.), La rupture ? La Grande Guerre, l'Europe et le XXe

	siècle	(Paris	:	IGPDE,	2021),	paragraph	23.	Disponible	sur	Internet	:

31

Badel, Laurence, « Reconstruire le monde en 1919 : la fausse « mondialisation » des <http://books.openedition.org/igpde/15145>. DOI : https://doi.org/10.4000/books.igpde.15145.

35

Idem, paragraph 13. 36 STEVENSON, David, « The First World War and European Integration », The International History Review, vol. 34, no 4, 2012, p. 841-863, p. 841. DOI : 10.1080/07075332.2012.690202

  Jay Winter, « British and Commonwealth Historiography of World War I: 1914-2018", in Writing the Great War: the Historiography of World War I from 1918 to the Present / edited by Christoph Cornelissen and Arndt Weinrich, New York : Berghahn Books, 2021, p. 95-113, p. 106.

47

Pollard, S., The Integration of the European Economy Since 1815 (London: George Allen & Unwin, 1981), p. 61.

On the Latin Monetary Union see Thiemeyer, Guido, Internationalisierung und Diplomatie. Währungspolitische Kooperation im europäischen Staatensystem 1865-1900, Studien zur

Conrad, S., Globalisation and the nation in imperial Germany (Cambridge (Mass.), Cambridge University Press, 2010), p. 27-76. With regard to old-age pensions C. Conrad, 'Die Entstehung des modernen Ruhestands', Geschichte und Gesellschaft

(1988), 417-47.

Bonin, Hubert, « La Société générale confrontée à la Première Guerre mondiale », dans Fabien Cardoni (dir.), Les banques françaises et la Grande Guerre, Paris, Comité pour l'histoire économique et financière de la France-Igpde, 2016, p. 75-104.

Clark, C. M., The Sleepwalkers: How Europe Went to War in 1914 (London: Penguin, 2014); Soutou, G.-H., La grande illusion. Comment la France a perdu la paix, 1914-1920 (Paris: Tallandier, 2016).

For a review of these interpretations: William Mulligan and Jack S. Levy, « Rethinking Power Politics in an Interdependent World, 1871-1914 », Journal of Interdisciplinary History, XLIX:4 (Spring, 2019), 611-640. The authors distinguish four main interpretations, to which they add a fifth: the separation between administrative internationalism and high politics; the lesser economic integration of the countries of Eastern Europe and the Balkans, which would have lowered the cost of a war for them; interdependence was, on the contrary, an aggravating factor, either by giving rise to trade conflicts, fanning imperial rivalries or pointing out vulnerabilities in the adversary, not to mention the losers of globalization arguing for more nationalist policies ; Finally, their interpretation is that interdependence stabilized the international system for a time, before destabilizing it by encouraging certain powers to using force (Austria-Hungary, Russia), because they were less able to take advantage of the new conditions for exercising and building power.

Forcade Olivier, « Le blocus en 1914-1918. Histoire et historiographie », Les Cahiers Sirice, 2021/1 (N° 26), p. 5-21.

See for instance BROADBERRY, S.N., O'ROURKE, K.H. (dir.), The Cambridge Economic History of Modern Europe, vol. 2 : 1870 to the Present, chapter 6 -War and disintegration, 1914-1950. New York, Cambridge University Press, 2010.

Carl Strikwerda, op. cit., 1128.

« Continuity and Change in European Cooperation during the Twentieth Century », Special issue, Contemporary European History, vol. 27, n° 2, 2018.

Georges-Henri Soutou : Europa ! Les projets européens de l'Allemagne nazie et de l'Italie fasciste, Paris, Tallandier, 2021.

Valentine Aldebert, Christian Henrich-Franke, Léonard Laborie, Sabrina Proschmann, Guido Thiemeyer (eds.), Conflict in Cooperation: Crossborder Infrastructures in Europe facing the Second World War, Baden-Baden, Nomos, coll. Historische Dimensionen Europäischer Integration, 2022.

BECUWE, Stéphane, BLANCHETON, Bertrand, « Le commerce extérieur français et la grande guerre : ruptures et continuités », Guerres mondiales et conflits contemporains, n° 266, 2017/2,

Léonard Laborie, Sébastien Richez, Attention, fragile ! Economie et politique de la messagerie postale en France, XIXe-XXe s., Bruxelles, Peter Lang, coll. Histoire de la Poste et des communications, 2020, 314 p., p. 183-185.

On the closely related subject of literary and artistic property, see Isabella Löhr, « Le droit d'auteur et la Première Guerre mondiale : un exemple de coopération transnationale européenne », Le

Mouvement social, 2013/3, n°244, p. 67-80. 61 This was the case in the field of intellectual property, where the temporary measures imposed by the Treaty of Versailles were quickly abandoned in favour of a return to the Berne Convention and its revision. Idem. 62 The 'rules' (in the broadest sense) that were imposed during the war on the transport, energy and food systems, as well as the 'meta-rules' that cut across these three systems, apparently did not endure as long after the first conflict as they did after the second. be seen as a pause or polar opposite of European integration, if only because the organisations and legislation in place before the war successfully survived the conflict. They emerged stronger from a potentially deadly cataclysm. In the end, perhaps the strongest mark left by the war on the techno-economic integration that preceded or was contemporary with it was its increasingly explicit or specific association with the future of Europe as a region of the world. 63 In short, the prospect of integration refocused on Europe, where neither peace nor war could be conceived without it. Whether Europe was seen as an area of peace or of domination, its techno-economic integration would be more a question of security for its members than of a vaguer "volonté générale", to use the expression typical of the nineteenth century. 64 With regard to European integration during the second half of the twentieth century, the German historian Werner Abelshauser has argued that European integration was pushed forward each time European security was at stake. The events that unfolded in the 1950s aptly confirm this argument. 65 The articles in this publication show that the issue of security was already characteristic for integration-related discussions during the First World War. Both Mitteleuropa concepts and Allied planning emphasized integration efforts in order to safeguard against aggression from their respective neighbours. Integration became a matter of protection rather than just pragmatic functionality, as was the case in previous instances of infrastructure coordination. In light of this, the matter of security actually predated institutional European integration. 63 It was the war that gave birth to "infrastructural Europeanism", the view that Europe's problems could be solved by building trans-European infrastructure. Schipper, F., & Schot, J. W., "Infrastructural Europeanism, or the project of building Europe on infrastructures : an introduction", History and


Gunter Mussbacher

Benoit Combemale

Jörg Kienzle

Lola Burgueño

Antonio Garcia-Dominguez

Jean-Marc Jézéquel

Gwendal Jouneaux

Djamel- Eddine Khelladi

Sébastien Mosser

Corinne Pulgar

Houari Sahraoui

Maximilian Schiedermeier

Tijs Van Der Storm

Polyglot Software Development: Wait, What?

The notion of polyglot software development refers to the fact that most software projects nowadays rely on multiple languages to deal with widely different concerns, from core business concerns to user interface, security, and deployment concerns among many others. Many different wordings around this notion have been proposed in the literature, with little understanding of their differences. In this article, we propose a concise and unambiguous definition of polyglot software development including a conceptual model and its illustration on a well-known, open-source project. We further characterize the techniques used for the specification and operationalization of polyglot software development with a feature model, concentrating on polyglot programming. We conclude the article outlining the many challenges and perspectives raised by polyglot software development.

Modern software development commonly requires the use of several languages in almost all activities, whether it is requirements engineering, programming in one or more languages, or continuous integration and delivery. For example, requirements may be specified using templates for use cases or user stories and Gherkin scenarios [START_REF] Murtazina | Ontologybased approach to the requirements engineering in agile environment[END_REF]. Continuous integration and delivery may be specified with GitHub Actions and build languages such as Maven or Gradle [START_REF] Shahin | Continuous integration, delivery and deployment: a systematic review on approaches, tools, challenges and practices[END_REF]. The proliferation of domainspecific languages further adds to the incentive to use different languages for an activity [START_REF] Kosar | Domainspecific languages: A systematic mapping study[END_REF]. Even a so-called Ruby project such as Mastodon, an open-source, distributed socialmedia platform, in fact already uses many languages [START_REF] Raman | Challenges in the decentralised web: The mastodon case[END_REF]. Besides Ruby, specifications in Docker Compose, Dockerfile, GitHub Actions, Haml, HTML, JavaScript, package.json, Rakefile, SCSS, and SQL are used to handle UI, persistence, and build issues. Mastodon is not an isolated example. In 2017, Mayer et [START_REF] Mayer | On multilanguage software development, cross-language links and accompanying tools: a survey of professional software developers[END_REF].

There are many reasons for why several languages are used in combination: sociotechnical reasons such as practitioners's expertise/preferences and best practices; conceptual reasons such as separation of concerns, design decisions, and variability management; technical reasons such as availability of libraries/functionality, efficiency, automation/reproduction, reasoning/analysis, and quality assurance; and business reasons such as coping with legacy applications/systems, technological debt, and vendorlock in.

It is therefore no surprise that many communities are investigating the combination of several languages [START_REF] Degueule | Melange: A meta-language for modular and reusable development of dsls[END_REF]. Yet, a long and ambiguous list of terms exists for polyglot software development from different communities. We illustrated all the terms we discovered in Figure 1, and also provide references to representative papers in the scientific literature that use that terminology. While by no means exhaustive, this list already showcases the lack of a common view, that is to say: different communities often use the same term with different meanings, or use different terms for the same meaning. The effect is a vastly ambiguous picture of the term polyglot, as well as a merely blurry sketch of common associated implications for a development process. Our goal is to clarify this fuzziness by providing a clear definition of polyglot software development. In turn, this may qualify as a common denominator for individual domain experts, to leverage an anti-silo effect that facilitates the exchange of contained knowledge.

In the remainder of this article, we first introduce a conceptual model for polyglot software development that allows us to clearly define polyglot software development, its polyglot processes and tasks, and whether polyglot stakeholders are required. We exemplify the conceptual model with Mastodon and other examples. We further characterize polyglot software development and elaborate on polyglot programming, before concluding with open challenges and perspectives.

Conceptual Model

To unify the large variety of terms related to the use of languages, this section proposes a conceptual model for software development with multiple languages in Figure 2. Note that we focus only on those development concepts that directly involve or somehow relate to languages.

At the heart of our conceptual model is the Task, which is a unit of work (e.g., "specify web views") that involves a set of Stake-holderRoles (e.g., "developer"). One Stakeholder may play one or more stakeholder roles. A task requires the use of one or several Artifacts expressed in one or more Languages, because the artifacts are either consumed as input or produced as output by the task. Some artifacts may be integrated with each other using one or several Integra-tionTechniques. A language offers one or more Paradigms in which to formulate the intended properties or behavior of the system under development (e.g., "object-oriented programming", "functional programming", and "procedural programming" for Ruby).

An important distinction for a stakeholder role to be associated with an artifact of a language is that the role needs to actively edit something in the artifact (e.g., write code, add a model element). If this is not the case, then the stakeholder does not use the language. Simply viewing or executing an artifact does not qualify (e.g., the result of a model generation or compilation, respectively). For example, while the task of compiling code will require an input artifact and will output bytecode/machine code, most stakeholders will not directly engage with the compilation results. Hence, the stakeholders do not use the bytecode/machine code language nor do they use the language of the input artifact since they do not edit it.

A ternary association is required since an artifact may be expressed in several languages and a stakeholder role may only use some of those languages. For example, a performance specialist may edit only the MARTE annotations in a UML class diagram.

To bring artifacts of languages together for a task, a certain IntegrationTechnique is used, where each artifact and its language(s) play a role, captured in the conceptual model by the qualified associations between integration technique and artifact and between integration technique and language.

For example, the "specify web views" task in Mastodon involves the creation of a "Haml" output artifact for the front-end developer and a "Ruby" output artifact for the back-end developer. These developers may in fact be the same person, as a stakeholder may play multiple roles. Since this is a task that requires integrating two or more languages, the task uses an integration technique where Haml plays the role of "template" and Ruby is the "interpreter". The follow-up runtime task "generate web views" that produces artifacts in "HTML" from the integrated Haml+Ruby specifications is a task that involves no editing stakeholders, but has two input artifacts and one output artifact.

Finally, during software development, tasks are typically performed in some order. For this purpose our conceptual model contains the Process concept which groups a set of tasks and a set of stakeholders. For the sake of practicality we also allow processes to contain subprocesses, i.e., to form hierarchies. We are not explicitly modelling the partial ordering of tasks within a process, though, as it is of no relevance regarding our discussion on polyglotism. Implicitly a partial ordering is established nevertheless, because tasks that require input artifacts can only be performed once the artifacts have been output by a preceding task in the process.

To finalize, we need to make the definition of a task more precise to avoid confusion between process, subprocesses, and tasks. A task is supposed to be the smallest unit of work, i.e., it should not arbitrarily consist of artifacts with many languages that are not directly related to each other (e.g., one task is defined for a whole process instead of splitting the process into several atomic tasks). We can do this by adding a constraint to the conceptual model.

A task may only contain artifact(s) of more than one language if the languages are integrated by a technique. In the Mastodon project, for example, an activity such as "specify web views and build script" that includes Ruby, Haml, and Dockerfile, would have to be modelled as two tasks.

Polyglotism

Since the production of software always involves translation from human readable languages to machine languages, all software development can be seen as polyglot. However, we are going to give a more nuanced definition of polyglot based on the use of languages for a task as explained earlier.

The conceptual model introduced allows for thinking about polyglotism at multiple levels, i.e., at the task and the process level, and also with respect to stakeholder roles and stakeholders.

A task is polyglot if the stakeholder roles of the task edit artifact(s) in more than one language.

context Task def isPolyglot(): Boolean = roles.usedLanguages→asSet()→size() ≥ 2

For example, consider a task "specify web page" with an output artifact in two languages, i.e., HTML and CSS. The task could require two stakeholder roles, one for HTML and one for CSS, or the same stakeholder role for both languages. In both cases the task is polyglot, and an integration technique is required because two languages are used in an edited artifact. Another common situation occurs when a low-level language is embedded within a high-level programming language. For example, it is common to embed C code in Python for increasing performance of computationally expensive algorithms, and therefore any programming task with such a setup is polyglot. However, if the task is fully automated, i.e., there is no stakeholder role, then the task is not polyglot. A polyglot task requires active stake-holder involvement with multiple languages.

This distinction is also exemplified by the tasks "write model transformation" and "run model transformation". Both tasks are not polyglot. The former is not polyglot because it involves a stakeholder role that edits the output artifact in only a single language, e.g., an ATL script for the model transformation, based on two input artifacts, i.e., the metamodels for the source and target languages of the transformation. The latter is not polyglot because it is automated and does not involve an active stakeholder role but three input artifacts (e.g., the ATL script and two models corresponding to the source and target metamodels) and an automatically created output artifact in the target language.

Similarly, the specification of a consistency rule or an analysis script (e.g., energy consumption for web pages) are tasks that are not polyglot unless the specification itself requires multiple languages. The metamodels of the languages for which a consistency rule is specified are the input artifacts and not edited. Likewise, the web pages that are analyzed are also input artifacts that are not edited. The execution of the consistency rule (which may perform changes to the input models) and the running of the analysis are automated, and hence they are not polyglot because no stakeholder is actively involved.

Based on the definition of a polyglot task, similar definitions for stakeholder roles, stakeholders, and processes can be formulated.

A stakeholder role is polyglot if it requires to edit artifact(s) in more than one language.

context StakeholderRole def : isPolyglot(): Boolean = usedLanguages→asSet()→size() ≥ 2

A stakeholder needs to be polyglot if the union of roles they play edit artifact(s) in more than one language.

context Stakeholder def : isPolyglot(): Boolean = roles.usedLanguages→asSet()→size() ≥ 2

A process is polyglot if the stakeholder roles of the tasks that it or any of its subprocesses contains edit artifact(s) in more than one language.

context Process def : isPolyglot(): Boolean = self.closure(subprocesses).tasks.roles.usedLanguages →asSet()→size() ≥ 2

For example, the earlier Ruby+Haml "specify web views" task has task-level polyglotism, but some other systems may exhibit processlevel polyglotism. For example, in a "data visualization" process, one task may use Python to transform data, and another task may use R to visualize the transformed data. At the uppermost process level, many modern systems will exhibit polyglotism (e.g., using a formal requirements language and an implementation language). On the other hand, there are still many projects which are not polyglot. For instance, there are numerous domains such as data science, biology, or finance whose projects use a single language (such as Python) for all tasks (e.g., data curation, analysis, computation, visualization, etc.). Such a task is represented in the conceptual model by a task that produces an output artifact edited by a stakeholder role but only in the Python language and without any integration technique.

In literature and practice, different communities refer to the concepts in our conceptual model differently. This existing terminology (cf.

Figure 1) can be mapped to our conceptual model as follows. "Polyglot development/programming" is in line with our definition of polyglotism.

Within it, "multi-paradigm modeling/globalization" are seminal approaches with an explicit focus on language integration (or composition) techniques. "Polyglot programming" and "Polylingual software", as well as "multi-language development" refer to a development process with tasks that span more than one language, but multi-language development is more general and refers to approaches without language integration technique. These terms should not be confused with "multi-lingual" software development tools, which include all language-agnostic tools that can be reused across a well-defined range of existing languages. "Cross-language" refers to tools that can operate across multiple languages while relating them (e.g., when performing clone detection across Java and Python programs, the tool not only has to work on both Java and Python programs, but also has to relate them). "Multi-language tools and development environments" focus on the tooling aspect, but do not contribute to the underlying foundations of software development with multiple languages. In contrast, "language composition" techniques refers to work on the foundations for dealing with multiple languages, which may involve polygot development, but also language design and implementation for hybrid programming languages, i.e., with multiple paradigms, but without language integration techniques. Finally, "hybrid programming" refers to a single language that combines more than one paradigm (e.g., continuous and discrete programming).

All communities depicted in Figure 1 build on the foundations of model-driven engineering (MDE) as well as language-oriented programming (LOP). In MDE, models play a central role during software developent, as the whole software life cycle is seen as a process of model production, refinement, and integration [START_REF] Schmidt | Model-driven engineering[END_REF]. Similary, in LOP a language is treated like any other development artifact and instead of using general-purpose languages, the creation and implementation of domain-specific languages for solving problems is preferred [START_REF] Pickering | Language-Oriented Programming[END_REF].

Integration Techniques

In this section, we provide more details on existing language integration techniques mentioned in the conceptual model by focusing on polyglot programming and hence executable artifacts. Figure 2 depicts the possible choices for the integration technique of executable artifacts as a feature model. Each feature represents a choice.

Each integration technique requires at least one choice for its Specification and one for its Operationalization. The former handles how we define the interaction between languages at design time, and the latter specifies how the interaction is realized during execution. The specification can be implemented with a Composition solution [START_REF] Kienzle | A unifying framework for homogeneous model composition[END_REF] and/or Interoperability solution [START_REF] Grimmer | Cross-language interoperability in a multilanguage runtime[END_REF]. Composition covers all various techniques from embedding of a language into another to unifying two languages at the syntax and/or semantic levels. We do not provide further details on the many existing composition techniques and their classification, but the interested reader is referred to this survey paper [START_REF] Erdweg | Language composition untangled[END_REF].

Interoperability covers the communication between different languages. Interoperability needs to deal with two important aspects, namely how data sharing (SharedData) and Calls are handled. The calls between languages can either be Remote, when the call goes through a network, or else Local. The shared data can either be implemented with a SharedMemory, a data streaming mechanism (DataStream), or simply by one language writing some output that another language consumes as an input, for example through a file on disk (OutputInput).

Operationalization represents how the specification will be realized during execution. This can either be achieved through Compilation and/or Interpretation, i.e., either by executing the relationships between the two lan-guages at compile-time, e.g., Melange [START_REF] Degueule | Melange: A meta-language for modular and reusable development of dsls[END_REF], or by interpreting the specified relationships at runtime, e.g., BCOoL [START_REF] Vara Larsen | A behavioral coordination operator language (bcool)[END_REF].

For example, a Scala program calling Java libraries fits the following choices in the feature model of Figure 2: shared memory and local call interoperability, and compilation operationalization. Another example is the case where code in one language invokes code in another language, e.g., the new Foreign Function and Memory (FFM) API in Java allows Java code to invoke low-level code and access data outside the JVM on the same machine. In other cases, interoperability happens through the use of an interface definition language, e.g., OpenAPI, from which client and server stubs are generated. This integration technique would use output/input and remote call interoperability. If, for example, Python talks to compiled C++, then the operationalization would use interpretation on the Python side and compilation on the C++ side.

Taking again the example of Mastodon, different integration techniques are used at various times. For instance, the integration technique between Haml and Ruby uses interoperability as specification through local calls to Haml code as well as shared memory, and is operationalized using the Haml interpreter. A second used integration technique between Ruby and JavaScript relies on interoperability as specification with a data stream using Redis and remote calls, and interpretation as operationalization.

As mentioned in the previous section, not every integration technique is associated with a polyglot task because stakeholder involvement is required. A fully automated task that is not polyglot may still have an integration technique. However, the earlier integration techniques between Haml and Ruby and between Ruby and JavaScript belong indeed to polyglot tasks, since the stakeholders edit artifacts in all languages.

Challenges and Perspectives

As mentioned above, most software development is already polyglot to some extent, and it is not surprising that we see more and more languages appear in modern software projects, e.g., in order to build systems more efficiently or to separate concerns (see sidebar). Polyglot software development, however, faces many technical, process-related, educational, and community challenges. We discuss them and provide related perspectives.

Technical Challenges and Perspectives

Some software development activities that are well understood within a single language become challenging in polyglot software development. For example, we need to develop novel and intuitive tools and techniques for polyglot software comprehension, polyglot software analysis (including, e.g., semantic alignment, debugging, and profiling) and polyglot software documentation. Similarly, whereas testing each language separately is well supported, testing the overall polyglot program and its different interactions remains a challenge. Indeed, a test case would require to integrate the "oracle states" of different programs written in different languages.

Techniques for software security will have to be revisited in the context of polyglot software development. For example, we need to ensure secure communication channels between languages and enable cross-language access control.

When developing polyglot programs, we often have to write the language integration logic from scratch. As a first step, our current code generators should be extended with a layer that automatically exposes the services by system components written in one language to the other languages. Ultimately, the goal is to have full-fledged code generation for polyglot programs that includes the integration logic.

Finally, new opportunities await with the application of AI techniques to polyglot software development.

More specifically, we should investigate how to capitalize on multilingual trained LLMs [START_REF] Ahmed | Multilingual training for software engineering[END_REF].

Process-Related Challenges and Perspectives

We must develop strategies to determine the most appropriate combination of languages to use for a given task, also taking into account the socio-technical context. We might even benefit from identifying anti-patterns of language combinations from unsuccessful projects. We need to develop a theory for tradeoffs between productivity and complexity involved with polyglotism. Adding a language that is well suited to a task can speed up development, but it might also increase the cognitive load for the developer and require a broader range of development skills. Finally, a completely new challenge arises regarding language evolution. As many languages are used and interact with each other, when one evolves, others may be impacted as well. We would need to develop tools and techniques for polyglot impact analysis that can reason over multiple languages simultaneously. Then, when impacts are identified, they must be considered and languages have to co-evolve accordingly.

Educational Challenges and Perspectives

Most software engineering curricula contain courses that teach languages and paradigms, but only rarely students are explicitly exposed to polyglot software development with dedicated support for the coordinated use of multiple languages [START_REF] Ardis | Se 2014: Curriculum guidelines for undergraduate degree programs in software engineering[END_REF]. We need to find ways to use the presented conceptual model as an edu-cation tool to convey the real-life complexities to students who are used to "lab" projects, as well as augment our teaching practices with examples of polyglot development activities and techniques to give a more holistic view of reallife software development.

Community Challenges and Perspectives

In this paper, we have identified similarities and variabilities in the terminology related to polyglot development used by various software engineering communities. Traditionally, different communities have been working in relative isolation from each other, and work like the one presented here can help break down the silos that separate them. Yet this work needs to be amended by the plethora of other communities dealing with polyglotism to enable global cross-fertilization.

Sidebar

To make a program it takes a language and a machine. One language, and a machine. At least in theory. But practice asks for separation of concerns, a division of labor between you, and me, and her. The people demand speed and efficiency, but alas, a language can compute anything, but is it fast? So then we invite another and thus transgress out of paradise with a bite, a sudden kiss of death, and descend the tarpit of our festished Babylon, sentenced to tame the Hydra that we have spawned. Let's study the techniques of our tongues' embrace: A language alongside another wants to communicate. A language on top of another is one that generates. A language within a language, a hatch for my escape.

So many tradeoffs at stake when complexity procreates.

Tijs van der Storm

Figure 2 :

 2 Figure 2: Conceptual Model for Polyglot Software Development and Feature Model Illustrating Different Integration Techniques

  context Task: inv: roles.usedLanguages→asSet()→size() ≥ 2 implies techniques.artifacts→includesAll(roles.editedArtifacts) and techniques.languages→includesAll(roles.usedLanguages)

  al. con-1 Legend 1. "Lightweight Multilingual Software Analysis" doi.org/10.48550/arXiv.1808.01210 2. "CLCDSA: Cross Language Code Clone Detection using Syntactical Features and API Documentation" doi.org/10.1109/ASE.2019.00099 3. "On Multi-Language Software Development, Cross-Language Links and Code Smells for Multi-language Systems" doi.org/10.1145/3361149.3361161 8. "An Empirical Assessment of Polyglot-ism in GitHub" doi.org/10.1145/2601248.2601269 "Investigating the Effect of Polyglot Programming on Developers"

	Cross-Language 2	Multi-Language Development	6	Multi-Language Tools and Development Environments.
	Multi-Lingual	1	4	3	Polyglot Programming / Polylingual Software 8 Multi-Paradigm	7 9	5	Hybrid Programming
					Modeling / Globalization	10	11	12
							Language Composition
			Figure 1: Ambiguous Terms Related to Polyglot Software Development
	ducted a survey to gather responses from 139
	professional software developers who reported
	an average of 7 languages per project, with over
	90% of developers reporting problems related
	to language interactions

Accompanying Tools: a Survey of Professional Software Developers" doi.org/10.1186/s40411-017-0035-z 4. "Cross-Language Interoperability in a Multi-Language Runtime" doi.org/10.1145/3201898 5. "The Design Space of Multi-Language Development Environments" doi.org/10.1007/s10270-013-0376-y 6. "Multilanguage Debugger Architecture" doi.org/10.1007/978-3-642-11266-9_61 7. "Debug All Your Code: Portable Mixed-environment Debugging" doi.org/10.1145/1640089.1640105 "doi.org/10.1109/VL/HCC51201.2021.9576404 "Automated Support for Seamless Interoperability in Polylingual Software Systems" doi.org/10.1145/250707.239123 9. "Multi-paradigm modeling for cyber-physical systems: A systematic mapping review" doi.org/10.1016/j.jss.2021.111081 10. "Globalizing Modeling Languages" doi.org/10.1109/MC.2014.147 11. "Language Composition Untangled" doi.org/10.1145/2427048.2427055 12. "A Hybrid Synchronous Language with Hierarchical Automata: Static Typing and Translation to Synchronous Code" doi.org/10.1145/2038642.2038664

Biographies

Prof.

Gunter Mussbacher is an Associate Professor at McGill University.

His research interests include Model-Driven Requirements Engineering, Software Language Engineering, Next-Generation Reuse Frameworks, Sustainability, and Human Values. More information about him can be found at http://www.ece.mcgill.ca/ ~gmussb1/. Contact him at gunter.mussbacher@mcgill.ca.

Prof. Benoit Combemale is Full Professor of Software Engineering at the University of Rennes, France. He is teaching at the engineering school ESIR, and he is co-head of the DiverSE research team, joint between the IRISA and Inria labs. He is also adjunct researcher in the team SM@RT of the IRIT labs, Toulouse, France, scientific advisor of the startup Twi-inIT, and Editor in Chief of the Springer Nature Journal on Software and Systems Modeling (SoSyM). His research interests include Model-Driven Engineering (MDE), software language engineering (SLE), software validation & verification (V&V) and DevOps. More information at http://combemale.fr/. Contact him at benoit.combemale@irisa.fr.

Prof. Jörg Kienzle is a researcher at ITIS Software, Universidad de Málaga, Málaga, Spain, and Full Professor at McGill University, Montréal, Québec, Canada, where he leads the Software Composition and Reuse lab (SCORE). His research interests include model-driven software development, software product lines, separation of concerns, reuse, software composition, and modularity. Further information about him can be found at https://djeminy.github.io. Contact him at Joerg.Kienzle@uma.es or Joerg.Kienzle@mcgill.ca.

Prof. Lola Burgueño is an Associate Professor at the University of Málaga, Spain. Her research interests include the application of artificial intelligence to improve software development processes and tools, uncertainty management during the software design phase, and model-based software testing. More information at https://lolaburgueno.github.io. Contact her at lolaburgueno@uma.es.

Dr. Antonio Garcia-Dominguez is a Lecturer in Software Engineering at the Department of Computer Science of the University of York, and a member of the Automated Software Engineering research group. Antonio's main research interests are model-driven software engineering (with lines of work on scalability of MDSE and on runtime models for explainability), and software testing (specifically, search-based testing and metamorphic testing). More information at https: //www-users.york.ac.uk/ ~agd516/. Contact him at a.garcia-dominguez@york.ac.uk.

Prof. Jean-Marc Jézéquel is a Professor at the University of Rennes and a member of the DiverSE team at IRISA/Inria. Since 2024 he is President of Informatics Europe. From 2012 to 2020 he was Director of IRISA, one of the largest public research lab in Informatics in France. Since Sept. 2023, he is a fellow of the Institut Universitaire de France (IUF). His interests include model-driven software engineering for software product lines. More information at http://people.irisa.fr/Jean-Marc.Jezequel. Contact him at jezequel@irisa.fr.


Filip Dámek

Bastien Fremaux

Dominique Aubert

Marieke Opsteegh

Sandra Thoumire

Delphine Le Roux

Sandra Vuillermet

Pikka Jokelainen

Joke Van Der Giessen

Pascal Boireau

Tropism and persistence of Toxoplasma gondii: from pork carcass to dry sausage

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

TROPISM Naturally infected pigs

Experimentally infected pigs (oocysts vs tissue cysts)

TROPISM AND PERSISTENCE OF TOXOPLASMA GONDII:

from pork carcass to dry sausage

RESULTS

filip.damek@vet-alfort.fr

# 108

 108 This work was co-funded from the TOXOSOURCES and ToxSauQMRA projects funded by the European Union's Horizon 2020 Research and Innovation programme under grant agreement No. 773830: One Health European Joint Programme, France-Agri-Mer: contract number 0917003490 and Med-Vet-Net European network of Excellence for Zoonoses research.

•Figure 1 .

 1 Figure1. Parasite burden estimates based on MC-qPCR method, visualized for each of the three pig groups, and the tissue examined.

Figure 2 .

 2 Figure 2. Results of mouse bioassay.

Filip Dámek 1 , Bastien Fremaux 2 , Dominique Aubert 3 , Marieke Opsteegh 4 , Sandra Thoumire 1 , Delphine Le Roux 1 , Sandra Vuillermet 1 , Pikka Jokelainen 5 , Joke van der Giessen 4 , Pascal Boireau 1 , Maxime Delsart 6 , Isabelle Villena 3 , Radu Blaga 1 1

  Anses, INRAE, Ecole Nationale Vétérinaire d'Alfort, Laboratoire de Santé Animale, BIPAR, Maisons-Alfort, France, 2 IFIP -Institut du Porc, Maisons-Alfort, France, 3 National Reference Center on Toxoplasmosis, Toxoplasma Biological Resources Center, CHU Reims and EA7510, SFR CAP-Santé, University of Reims Champagne-Ardenne, USC EpiToxo ANSES, France, 4 Centre for Infectious Disease Control -Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment, Bilthoven, the Netherlands, 5 Statens Serum Institut, Infectious Disease Preparedness, Copenhagen, Denmark, 6 EPIMAI, USC Anses, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France