Add alternative iterator protocol for foreach

If the iterator object has a .next_value() function that returns a
nullable type then we iterate by calling this function until it returns
null.

Fixes bug 609812.

diff --git a/vala/valaforeachstatement.vala b/vala/valaforeachstatement.vala
index 0975c82d48e0cb71e8042cfe25fc76149f552da0..401e43aa2307053039a6ff1f3ccf99a928af5de8 100644 (file)
--- a/vala/valaforeachstatement.vala
+++ b/vala/valaforeachstatement.vala
@@ -209,40 +209,86 @@ public class Vala.ForeachStatement : Block {
                        error = true;
                        return false;
                }
+
+               var iterator_call = new MethodCall (new MemberAccess (collection, "iterator"));
+               add_statement (new DeclarationStatement (new LocalVariable (iterator_type, "_%s_it".printf (variable_name), iterator_call, source_reference), source_reference));
+
+               var next_value_method = iterator_type.get_member ("next_value") as Method;
                var next_method = iterator_type.get_member ("next") as Method;
-               if (next_method == null) {
-                       Report.error (collection.source_reference, "`%s' does not have a `next' method".printf (iterator_type.to_string ()));
-                       error = true;
-                       return false;
-               }
-               if (next_method.get_parameters ().size != 0) {
-                       Report.error (collection.source_reference, "`%s' must not have any parameters".printf (next_method.get_full_name ()));
-                       error = true;
-                       return false;
-               }
-               if (!next_method.return_type.compatible (analyzer.bool_type)) {
-                       Report.error (collection.source_reference, "`%s' must return a boolean value".printf (next_method.get_full_name ()));
-                       error = true;
-                       return false;
-               }
-               var get_method = iterator_type.get_member ("get") as Method;
-               if (get_method == null) {
-                       Report.error (collection.source_reference, "`%s' does not have a `get' method".printf (iterator_type.to_string ()));
-                       error = true;
-                       return false;
-               }
-               if (get_method.get_parameters ().size != 0) {
-                       Report.error (collection.source_reference, "`%s' must not have any parameters".printf (get_method.get_full_name ()));
-                       error = true;
-                       return false;
-               }
-               var element_type = get_method.return_type.get_actual_type (iterator_type, null, this);
-               if (element_type is VoidType) {
-                       Report.error (collection.source_reference, "`%s' must return an element".printf (get_method.get_full_name ()));
+               if (next_value_method != null) {
+                       if (next_value_method.get_parameters ().size != 0) {
+                               Report.error (collection.source_reference, "`%s' must not have any parameters".printf (next_value_method.get_full_name ()));
+                               error = true;
+                               return false;
+                       }
+                       var element_type = next_value_method.return_type.get_actual_type (iterator_type, null, this);
+                       if (!element_type.nullable) {
+                               Report.error (collection.source_reference, "return type of `%s' must be nullable".printf (next_value_method.get_full_name ()));
+                               error = true;
+                               return false;
+                       }
+
+                       if (!analyze_element_type (element_type)) {
+                               return false;
+                       }
+
+                       add_statement (new DeclarationStatement (new LocalVariable (type_reference, variable_name, null, source_reference), source_reference));
+
+                       var next_value_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "next_value", source_reference), source_reference);
+                       var assignment = new Assignment (new MemberAccess (null, variable_name, source_reference), next_value_call, AssignmentOperator.SIMPLE, source_reference);
+                       var conditional = new BinaryExpression (BinaryOperator.INEQUALITY, assignment, new NullLiteral (source_reference), source_reference);
+                       var loop = new WhileStatement (conditional, body, source_reference);
+                       add_statement (loop);
+               } else if (next_method != null) {
+                       if (next_method.get_parameters ().size != 0) {
+                               Report.error (collection.source_reference, "`%s' must not have any parameters".printf (next_method.get_full_name ()));
+                               error = true;
+                               return false;
+                       }
+                       if (!next_method.return_type.compatible (analyzer.bool_type)) {
+                               Report.error (collection.source_reference, "`%s' must return a boolean value".printf (next_method.get_full_name ()));
+                               error = true;
+                               return false;
+                       }
+                       var get_method = iterator_type.get_member ("get") as Method;
+                       if (get_method == null) {
+                               Report.error (collection.source_reference, "`%s' does not have a `get' method".printf (iterator_type.to_string ()));
+                               error = true;
+                               return false;
+                       }
+                       if (get_method.get_parameters ().size != 0) {
+                               Report.error (collection.source_reference, "`%s' must not have any parameters".printf (get_method.get_full_name ()));
+                               error = true;
+                               return false;
+                       }
+                       var element_type = get_method.return_type.get_actual_type (iterator_type, null, this);
+                       if (element_type is VoidType) {
+                               Report.error (collection.source_reference, "`%s' must return an element".printf (get_method.get_full_name ()));
+                               error = true;
+                               return false;
+                       }
+
+                       if (!analyze_element_type (element_type)) {
+                               return false;
+                       }
+
+                       var next_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "next", source_reference), source_reference);
+                       var loop = new WhileStatement (next_call, body, source_reference);
+                       add_statement (loop);
+
+                       var get_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "get", source_reference), source_reference);
+                       body.insert_statement (0, new DeclarationStatement (new LocalVariable (type_reference, variable_name, get_call, source_reference), source_reference));
+               } else {
+                       Report.error (collection.source_reference, "`%s' does not have a `next_value' or `next' method".printf (iterator_type.to_string ()));
                        error = true;
                        return false;
                }
 
+               checked = false;
+               return base.check (analyzer);
+       }
+
+       bool analyze_element_type (DataType element_type) {
                // analyze element type
                if (type_reference == null) {
                        // var type
@@ -257,18 +303,7 @@ public class Vala.ForeachStatement : Block {
                        return false;
                }
 
-               var iterator_call = new MethodCall (new MemberAccess (collection, "iterator"));
-               add_statement (new DeclarationStatement (new LocalVariable (iterator_type, "_%s_it".printf (variable_name), iterator_call, source_reference), source_reference));
-
-               var next_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "next", source_reference), source_reference);
-               var loop = new WhileStatement (next_call, body, source_reference);
-               add_statement (loop);
-
-               var get_call = new MethodCall (new MemberAccess (new MemberAccess.simple ("_%s_it".printf (variable_name), source_reference), "get", source_reference), source_reference);
-               body.insert_statement (0, new DeclarationStatement (new LocalVariable (type_reference, variable_name, get_call, source_reference), source_reference));
-
-               checked = false;
-               return base.check (analyzer);
+               return true;
        }
 
        bool check_without_iterator (SemanticAnalyzer analyzer, DataType collection_type, DataType element_type) {