Handle mutually recursive record definitions

souffle-lang · May 12, 2020 · 499462e · 499462e
1 parent 986d01b
commit 499462e
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Showing 4 changed files with 18 additions and 9 deletions.
diff --git a/src/AstTypeEnvironmentAnalysis.cpp b/src/AstTypeEnvironmentAnalysis.cpp
@@ -36,11 +36,11 @@ namespace {
 Graph<AstQualifiedName> createTypeDependencyGraph(const std::vector<AstType*>& programTypes) {
     Graph<AstQualifiedName> typeDependencyGraph;
     for (const auto* astType : programTypes) {
-        if (auto type = dynamic_cast<const AstSubsetType*>(astType)) {
+        if (auto type = as<AstSubsetType>(astType)) {
             typeDependencyGraph.insert(type->getQualifiedName(), type->getBaseType());
-        } else if (dynamic_cast<const AstRecordType*>(astType) != nullptr) {
+        } else if (isA<AstRecordType>(astType)) {
             // do nothing
-        } else if (auto type = dynamic_cast<const AstUnionType*>(astType)) {
+        } else if (auto type = as<AstUnionType>(astType)) {
             for (const auto& subtype : type->getTypes()) {
                 typeDependencyGraph.insert(type->getQualifiedName(), subtype);
             }
@@ -76,7 +76,7 @@ std::map<AstQualifiedName, std::set<AstQualifiedName>> analysePrimitiveTypesInUn
     std::map<AstQualifiedName, std::set<AstQualifiedName>> primitiveTypesInUnions;
 
     for (const auto& astType : programTypes) {
-        auto unionType = dynamic_cast<const AstUnionType*>(astType);
+        auto* unionType = as<AstUnionType>(astType);
         if (unionType == nullptr) {
             continue;
         }
@@ -166,11 +166,12 @@ const Type* TypeEnvironmentAnalysis::createType(
             }
             elements.push_back(elementType);
         }
-        return &env.createType<UnionType>(typeName, std::move(elements));
+        return &env.createType<UnionType>(typeName, elements);
 
     } else if (isA<AstRecordType>(astType)) {
         // Create anonymous base first.
         auto& recordBase = env.createType<RecordType>(tfm::format("__%sConstant", typeName));
+        auto& recordType = env.createType<SubsetRecordType>(typeName, recordBase);
 
         std::vector<const Type*> elements;
         for (const auto* field : as<AstRecordType>(astType)->getFields()) {
@@ -185,9 +186,11 @@ const Type* TypeEnvironmentAnalysis::createType(
             }
             elements.push_back(elementType);
         }
-        recordBase.setFields(std::move(elements));
 
-        auto& recordType = env.createType<SubsetRecordType>(typeName, recordBase);
+        recordBase.setFields(elements);
+        std::replace(elements.begin(), elements.end(), dynamic_cast<Type*>(&recordBase),
+                dynamic_cast<Type*>(&recordType));
+        recordType.setFields(std::move(elements));
 
         return &recordType;
 

diff --git a/src/AstTypeEnvironmentAnalysis.h b/src/AstTypeEnvironmentAnalysis.h
@@ -61,7 +61,8 @@ class TypeEnvironmentAnalysis : public AstAnalysis {
     std::set<AstQualifiedName> cyclicTypes;
 
     /**
-     * Recursively create a type in env. (eg: Subset -> construct base and then the type itself).
+     * Recursively create a type in env, that is
+     * first create its base types and then the type itself.
      */
     const Type* createType(const AstQualifiedName& typeName,
             const std::map<AstQualifiedName, const AstType*>& nameToAstType);

diff --git a/tests/semantic/extended_subtypes2/extended_subtypes2.dl b/tests/semantic/extended_subtypes2/extended_subtypes2.dl
@@ -30,6 +30,11 @@ relY(1).
 .type RecA = [a: RecA, b:Z]
 
 
+// Check if mutually recursive record type definitions work
+.type RecX = [y : RecY]
+.type RecY = [x : RecX]
+
+
 // Subtypes of unions are not allowed
 .type U = number
 

diff --git a/tests/semantic/extended_subtypes2/extended_subtypes2.err b/tests/semantic/extended_subtypes2/extended_subtypes2.err
@@ -13,7 +13,7 @@ Error: Undefined base type Z in definition of type Y in file extended_subtypes2.
 Error: Undefined type Z in definition of field b in file extended_subtypes2.dl at line 30
 .type RecA = [a: RecA, b:Z]
 -------------------------^--
-Error: Subset type W can't be derived from union U in file extended_subtypes2.dl at line 36
+Error: Subset type W can't be derived from union U in file extended_subtypes2.dl at line 41
 .type W <: U
 ^------------
 6 errors generated, evaluation aborted