Add basic type annotation support for QML functions to the grammar

Inspired by TypeScript syntax, allow optional type annotations in the
style of ": <name of type>" in for the parameters of functions and their
return type.

These annotations are not used at the moment, so by default we produce
an error message when encountering them in the AST.

In addition their usage is limited to functions declared in the QML
scope. All other uses attempt to produce readable syntax errors. So for
example this is okay:

    Item {
        function blah(param: string) string { ... }
    }

And this is not okay:

    // some file.js
    function blah(param: string) : string { ... }

Change-Id: I12d20b4e2ce92e01108132975a06cfd13ba4a254
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 136 insertions, 45 deletions

diff --git a/src/qml/parser/qqmljsast_p.h b/src/qml/parser/qqmljsast_p.h
index c62c11885f..21d143edf1 100644
--- a/src/qml/parser/qqmljsast_p.h
+++ b/src/qml/parser/qqmljsast_p.h
@@ -234,6 +234,9 @@ public:
         Kind_PatternElementList,
         Kind_PatternProperty,
         Kind_PatternPropertyList,
+        Kind_Type,
+        Kind_TypeArgumentList,
+        Kind_TypeAnnotation,
 
         Kind_UiArrayBinding,
         Kind_UiImport,
@@ -304,6 +307,128 @@ public:
     int kind = Kind_Undefined;
 };
 
+
+class QML_PARSER_EXPORT UiQualifiedId: public Node
+{
+public:
+    QQMLJS_DECLARE_AST_NODE(UiQualifiedId)
+
+    UiQualifiedId(const QStringRef &name)
+        : next(this), name(name)
+    { kind = K; }
+
+    UiQualifiedId(UiQualifiedId *previous, const QStringRef &name)
+        : name(name)
+    {
+        kind = K;
+        next = previous->next;
+        previous->next = this;
+    }
+
+    UiQualifiedId *finish()
+    {
+        UiQualifiedId *head = next;
+        next = nullptr;
+        return head;
+    }
+
+    void accept0(Visitor *visitor) override;
+
+    SourceLocation firstSourceLocation() const override
+    { return identifierToken; }
+
+    SourceLocation lastSourceLocation() const override
+    { return next ? next->lastSourceLocation() : identifierToken; }
+
+// attributes
+    UiQualifiedId *next;
+    QStringRef name;
+    SourceLocation identifierToken;
+};
+
+class QML_PARSER_EXPORT Type: public Node
+{
+public:
+    QQMLJS_DECLARE_AST_NODE(Type)
+
+    Type(UiQualifiedId *typeId, Node *typeArguments = nullptr)
+        : typeId(typeId)
+        , typeArguments(typeArguments)
+    { kind = K; }
+
+    void accept0(Visitor *visitor) override;
+
+    SourceLocation firstSourceLocation() const override
+    { return typeId->firstSourceLocation(); }
+
+    SourceLocation lastSourceLocation() const override
+    { return typeArguments ? typeArguments->lastSourceLocation() : typeId->lastSourceLocation(); }
+
+// attributes
+    UiQualifiedId *typeId;
+    Node *typeArguments; // TypeArgumentList
+};
+
+
+class QML_PARSER_EXPORT TypeArgumentList: public Node
+{
+public:
+    QQMLJS_DECLARE_AST_NODE(TypeArgumentList)
+
+    TypeArgumentList(Type *typeId)
+        : typeId(typeId)
+        , next(nullptr)
+    { kind = K; }
+
+    TypeArgumentList(TypeArgumentList *previous, Type *typeId)
+        : typeId(typeId)
+    {
+        kind = K;
+        next = previous->next;
+        previous->next = this;
+    }
+
+    void accept0(Visitor *visitor) override;
+
+    SourceLocation firstSourceLocation() const override
+    { return typeId->firstSourceLocation(); }
+
+    SourceLocation lastSourceLocation() const override
+    { return next ? next->lastSourceLocation() : typeId->lastSourceLocation(); }
+
+    inline TypeArgumentList *finish()
+    {
+        TypeArgumentList *front = next;
+        next = nullptr;
+        return front;
+    }
+
+// attributes
+    Type *typeId;
+    TypeArgumentList *next;
+};
+
+class QML_PARSER_EXPORT TypeAnnotation: public Node
+{
+public:
+    QQMLJS_DECLARE_AST_NODE(TypeAnnotation)
+
+    TypeAnnotation(Type *type)
+        : type(type)
+    { kind = K; }
+
+    void accept0(Visitor *visitor) override;
+
+    SourceLocation firstSourceLocation() const override
+    { return colonToken; }
+
+    SourceLocation lastSourceLocation() const override
+    { return type->lastSourceLocation(); }
+
+// attributes
+    Type *type;
+    SourceLocation colonToken;
+};
 class QML_PARSER_EXPORT ExpressionNode: public Node
 {
 public:
@@ -729,8 +854,9 @@ public:
         : initializer(i), type(t)
     { kind = K; }
 
-    PatternElement(const QStringRef &n, ExpressionNode *i = nullptr, Type t = Binding)
+    PatternElement(const QStringRef &n, TypeAnnotation *typeAnnotation = nullptr, ExpressionNode *i = nullptr, Type t = Binding)
         : bindingIdentifier(n), initializer(i), type(t)
+        , typeAnnotation(typeAnnotation)
     {
         Q_ASSERT(t >= RestElement);
         kind = K;
@@ -750,7 +876,7 @@ public:
     { return identifierToken.isValid() ? identifierToken : (bindingTarget ? bindingTarget->firstSourceLocation() : initializer->firstSourceLocation()); }
 
     SourceLocation lastSourceLocation() const override
-    { return initializer ? initializer->lastSourceLocation() : (bindingTarget ? bindingTarget->lastSourceLocation() : identifierToken); }
+    { return initializer ? initializer->lastSourceLocation() : (bindingTarget ? bindingTarget->lastSourceLocation() : (typeAnnotation ? typeAnnotation->lastSourceLocation() : identifierToken)); }
 
     ExpressionNode *destructuringTarget() const { return bindingTarget; }
     Pattern *destructuringPattern() const { return bindingTarget ? bindingTarget->patternCast() : nullptr; }
@@ -768,6 +894,7 @@ public:
     ExpressionNode *bindingTarget = nullptr;
     ExpressionNode *initializer = nullptr;
     Type type = Literal;
+    TypeAnnotation *typeAnnotation = nullptr;
     // when used in a VariableDeclarationList
     VariableScope scope = VariableScope::NoScope;
     bool isForDeclaration = false;
@@ -820,7 +947,7 @@ public:
     { kind = K; }
 
     PatternProperty(PropertyName *name, const QStringRef &n, ExpressionNode *i = nullptr)
-        : PatternElement(n, i), name(name)
+        : PatternElement(n, /*type annotation*/nullptr, i), name(name)
     { kind = K; }
 
     PatternProperty(PropertyName *name, Pattern *pattern, ExpressionNode *i = nullptr)
@@ -2155,8 +2282,9 @@ class QML_PARSER_EXPORT FunctionExpression: public ExpressionNode
 public:
     QQMLJS_DECLARE_AST_NODE(FunctionExpression)
 
-    FunctionExpression(const QStringRef &n, FormalParameterList *f, StatementList *b):
-        name (n), formals (f), body (b)
+    FunctionExpression(const QStringRef &n, FormalParameterList *f, StatementList *b, TypeAnnotation *typeAnnotation = nullptr):
+        name (n), formals (f), body (b),
+        typeAnnotation(typeAnnotation)
         { kind = K; }
 
     void accept0(Visitor *visitor) override;
@@ -2175,6 +2303,7 @@ public:
     bool isGenerator = false;
     FormalParameterList *formals;
     StatementList *body;
+    TypeAnnotation *typeAnnotation;
     SourceLocation functionToken;
     SourceLocation identifierToken;
     SourceLocation lparenToken;
@@ -2188,8 +2317,8 @@ class QML_PARSER_EXPORT FunctionDeclaration: public FunctionExpression
 public:
     QQMLJS_DECLARE_AST_NODE(FunctionDeclaration)
 
-    FunctionDeclaration(const QStringRef &n, FormalParameterList *f, StatementList *b):
-        FunctionExpression(n, f, b)
+    FunctionDeclaration(const QStringRef &n, FormalParameterList *f, StatementList *b, TypeAnnotation *typeAnnotation = nullptr):
+        FunctionExpression(n, f, b, typeAnnotation)
         { kind = K; }
 
     void accept0(Visitor *visitor) override;
@@ -2810,44 +2939,6 @@ public:
     SourceLocation semicolonToken;
 };
 
-class QML_PARSER_EXPORT UiQualifiedId: public Node
-{
-public:
-    QQMLJS_DECLARE_AST_NODE(UiQualifiedId)
-
-    UiQualifiedId(const QStringRef &name)
-        : next(this), name(name)
-    { kind = K; }
-
-    UiQualifiedId(UiQualifiedId *previous, const QStringRef &name)
-        : name(name)
-    {
-        kind = K;
-        next = previous->next;
-        previous->next = this;
-    }
-
-    UiQualifiedId *finish()
-    {
-        UiQualifiedId *head = next;
-        next = nullptr;
-        return head;
-    }
-
-    void accept0(Visitor *visitor) override;
-
-    SourceLocation firstSourceLocation() const override
-    { return identifierToken; }
-
-    SourceLocation lastSourceLocation() const override
-    { return next ? next->lastSourceLocation() : identifierToken; }
-
-// attributes
-    UiQualifiedId *next;
-    QStringRef name;
-    SourceLocation identifierToken;
-};
-
 class QML_PARSER_EXPORT UiImport: public Node
 {
 public: