[Elm] Add support for array schemas (#7729)

The following schema definitions kinds are now supported:

MyStringArray:
  type: array
  items:
    type: string

MyObjectArray:
  type: array
  items:
    type: MyObject

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ElmClientCodegen.java

@@ -9,6 +9,8 @@ import io.swagger.codegen.CodegenResponse;
 import io.swagger.codegen.CodegenType;
 import io.swagger.codegen.DefaultCodegen;
 import io.swagger.codegen.SupportingFile;
+import io.swagger.models.ArrayModel;
+import io.swagger.models.Model;
 import io.swagger.models.Response;
 import io.swagger.models.parameters.Parameter;
 import io.swagger.models.properties.ArrayProperty;
@@ -103,6 +105,7 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
         );
 
         instantiationTypes.clear();
+        instantiationTypes.put("array", "List");
 
         typeMapping.clear();
         typeMapping.put("integer", "Int");
@@ -181,6 +184,17 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
         return camelized;
     }
 
+    @Override
+    public String toInstantiationType(Property p) {
+        if (p instanceof ArrayProperty) {
+            ArrayProperty ap = (ArrayProperty) p;
+            String inner = getSwaggerType(ap.getItems());
+            return instantiationTypes.get("array") + " " + inner;
+        } else {
+            return null;
+        }
+    }
+
     @Override
     public String escapeReservedWord(String name) {
         return name + "_";
@@ -196,6 +210,20 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
         return outputFolder + "/src/Data/" + modelPackage().replace('.', File.separatorChar);
     }
 
+    @Override
+    public CodegenModel fromModel(String name, Model model, Map<String, Model> allDefinitions) {
+        CodegenModel m = super.fromModel(name, model, allDefinitions);
+
+        if (model instanceof ArrayModel) {
+            ArrayModel am = (ArrayModel) model;
+            ArrayProperty arrayProperty = new ArrayProperty(am.getItems());
+            CodegenProperty codegenProperty = fromProperty(name, arrayProperty);
+            m.vendorExtensions.putAll(codegenProperty.vendorExtensions);
+        }
+
+        return m;
+    }
+
     @SuppressWarnings({ "static-method", "unchecked" })
     public Map<String, Object> postProcessAllModels(Map<String, Object> objs) {
         // Index all CodegenModels by model name.
@@ -245,6 +273,20 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
                         elmImports.add(createPropertyImport(property));
                     }
                 }
+                if (cm.isArrayModel) {
+                    if (cm.arrayModelType != null) {
+                        // add type imports
+                        final ElmImport elmImport = new ElmImport();
+                        final String modulePrefix = customPrimitives.contains(cm.arrayModelType) ? "" : "Data.";
+                        elmImport.moduleName = modulePrefix + cm.arrayModelType;
+                        elmImport.exposures = new TreeSet<>();
+                        elmImport.exposures.add(cm.arrayModelType);
+                        elmImport.exposures.add(camelize(cm.arrayModelType, true) + "Decoder");
+                        elmImport.exposures.add(camelize(cm.arrayModelType, true) + "Encoder");
+                        elmImport.hasExposures = true;
+                        elmImports.add(elmImport);
+                    }
+                }
                 if (cm.discriminator != null) {
                     for (CodegenModel child : cm.children) {
                         // add child imports

modules/swagger-codegen/src/main/resources/elm/aliasDecoder.mustache

@@ -1,5 +1,5 @@
 {{classVarName}}Decoder : Decoder {{classname}}
 {{classVarName}}Decoder =
-    decode {{classname}}
+    {{#parent}}Decode.list {{vendorExtensions.x-decoder}}{{/parent}}{{^parent}}decode {{classname}}
 {{#allVars}}{{^discriminatorValue}}        |> {{>fieldDecoder}}
-{{/discriminatorValue}}{{/allVars}}
+{{/discriminatorValue}}{{/allVars}}{{/parent}}

modules/swagger-codegen/src/main/resources/elm/aliasEncoder.mustache

@@ -1,7 +1,7 @@
 {{classVarName}}Encoder : {{classname}} -> Encode.Value
 {{classVarName}}Encoder model =
-    Encode.object
+    {{#parent}}Encode.list (List.map {{vendorExtensions.x-encoder}} model){{/parent}}{{^parent}}Encode.object
 {{#allVars}}
         {{#-first}}[{{/-first}}{{^-first}},{{/-first}} {{>fieldEncoder}}
 {{/allVars}}
-        ]
+        ]{{/parent}}

modules/swagger-codegen/src/main/resources/elm/modelTypeAlias.mustache

@@ -1,6 +1,6 @@
 
 
-type alias {{classname}} =
+type alias {{classname}} ={{#parent}} {{parent}}{{/parent}}{{^parent}}
     { {{#vars}}{{^-first}}    , {{/-first}}{{name}} : {{^required}}Maybe {{/required}}{{#isContainer}}(List {{/isContainer}}{{#isEnum}}{{nameInCamelCase}}{{/isEnum}}{{^isEnum}}{{datatype}}{{/isEnum}}{{#isContainer}}){{/isContainer}}
 {{/vars}}    }
 {{#vars}}
@@ -10,6 +10,7 @@ type alias {{classname}} =
 {{>union}}
 {{/isEnum}}
 {{/vars}}
+{{/parent}}
 
 
 {{>aliasDecoder}}