public override Statement VisitForEach(ForEach forEach)
{
WriteStart("foreach (");
this.VisitTypeReference(forEach.TargetVariableType);
Write(" ");
this.VisitExpression(forEach.TargetVariable);
Write(" in ");
this.VisitExpression(forEach.SourceEnumerable);
Write(")");
this.VisitBlock(forEach.Body);
return forEach;
}
void AddWriteStream(TypeNode type, StatementList statements, TypeNode referringType, Expression src, Identifier writer) {
// Generate the following code:
// XxxxSerializer s = new XxxxSerializer();
// foreach (Xxxx x in src) {
// s.Serialize(x,writer);
// }
// Where Xxxx is the element type for the given stream type.
if (type.Template == SystemTypes.GenericNonEmptyIEnumerable) {
type = Checker.GetIEnumerableTypeFromNonEmptyIEnumerableStruct(this.module, type);
} else {
statements = AddCheckForNull(statements, Duplicate(src, referringType), type);
}
TypeNode ceType = Checker.GetCollectionElementType(type);
//todo: should check that type has an IEnumerator.
Identifier loopVariable = Identifier.For("e");
loopVariable.Type = ceType;
Block body = new Block();
body.Statements = new StatementList();
Expression name, ns;
GetNameAndNamespace(ceType, out name, out ns);
// call the Serialize method on it, passing the member we're serializing.
if (!AddWriteSimpleType(ceType, body.Statements, referringType, writer, loopVariable, name, ns)) {
AddCallSerializer(ceType, body.Statements, loopVariable, writer, name, ns);
}
ForEach fe = new ForEach(ceType, loopVariable, src, body);
statements.Add(fe);
}
public override Statement VisitForEach(ForEach forEach)
{
Statement rVal = base.VisitForEach(forEach);
//
// Create a temporary variable to hold our enumerator position
//
forEach.ScopeForTemporaryVariables.Members.Add(
new Field(forEach.ScopeForTemporaryVariables, null, FieldFlags.Public,
new Identifier("____" + forEach.UniqueKey.ToString(CultureInfo.InvariantCulture)),
SystemTypes.Int32, new Literal(0, SystemTypes.Int32)));
// Add the local variables we've added here to the method's "locals" list.
Class scope;
for (scope = forEach.ScopeForTemporaryVariables; scope is BlockScope; scope = scope.BaseClass)
;
MethodScope mScope = scope as MethodScope;
Debug.Assert(mScope != null);
for (int i = 0, n = forEach.ScopeForTemporaryVariables.Members.Count; i < n; i++)
{
Member m = forEach.ScopeForTemporaryVariables.Members[i];
ZMethod zMethod = mScope.DeclaringMethod as ZMethod;
Debug.Assert(zMethod != null);
zMethod.LocalVars.Add((Field)m);
}
return rVal;
}
public override Statement VisitForEach(ForEach forEach)
{
if (forEach == null) return null;
return base.VisitForEach((ForEach)forEach.Clone());
}
public virtual Statement VisitForEach(ForEach forEach)
{
if (forEach == null) return null;
forEach.TargetVariableType = this.VisitTypeReference(forEach.TargetVariableType);
forEach.TargetVariable = this.VisitTargetExpression(forEach.TargetVariable);
forEach.SourceEnumerable = this.VisitExpression(forEach.SourceEnumerable);
forEach.InductionVariable = this.VisitTargetExpression(forEach.InductionVariable);
forEach.Invariants = this.VisitLoopInvariantList(forEach.Invariants);
forEach.Body = this.VisitBlock(forEach.Body);
return forEach;
}
private ForEach ParseForEach(TokenSet followers){
ForEach forEach = new ForEach();
forEach.StatementTerminatesNormallyIfEnumerableIsNull = false;
forEach.StatementTerminatesNormallyIfEnumeratorIsNull = false;
forEach.SourceContext = this.scanner.CurrentSourceContext;
Debug.Assert(this.currentToken == Token.Foreach);
this.GetNextToken();
SourceContext sctx = this.scanner.CurrentSourceContext;
this.Skip(Token.LeftParenthesis);
forEach.TargetVariableType = forEach.TargetVariableTypeExpression =
this.ParseTypeExpression(null, followers|Parser.IdentifierOrNonReservedKeyword|Token.In|Token.RightParenthesis);
forEach.TargetVariable = this.scanner.GetIdentifier();
if (this.currentToken == Token.In)
this.HandleError(Error.BadForeachDecl);
else
this.SkipIdentifierOrNonReservedKeyword();
this.Skip(Token.In);
forEach.SourceEnumerable = this.ParseExpression(followers|Token.RightParenthesis);
this.ParseBracket(sctx, Token.RightParenthesis, followers|Token.ElementsSeen|Token.Invariant|Parser.StatementStart, Error.ExpectedRightParenthesis);
if (this.currentToken == Token.ElementsSeen){
this.GetNextToken();
forEach.InductionVariable = this.scanner.GetIdentifier();
this.SkipIdentifierOrNonReservedKeyword();
this.SkipSemiColon(followers);
}
forEach.Invariants = this.ParseLoopInvariants(followers);
SourceContext savedCompoundStatementOpeningContext = this.compoundStatementOpeningContext;
forEach.SourceContext.EndPos = this.scanner.endPos;
this.compoundStatementOpeningContext = forEach.SourceContext;
Block b = this.ParseStatementAsBlock(followers);
forEach.Body = b;
if (b != null)
forEach.SourceContext.EndPos = b.SourceContext.EndPos;
this.compoundStatementOpeningContext = savedCompoundStatementOpeningContext;
return forEach;
}
/// <summary>
/// To be C# compliant, we should not allow anything to be the source of a foreach loop (which includes
/// comprehensions) unless it either has a GetEnumerator() method or if it is an array.
/// (It used to be that we would happily use something that was already an Enumerator, but that leads
/// to a problem: once the enumerator is exhausted, there is not necessarily a good, automatic, way to
/// reset it. And there isn't necessarily a good way to clone it beforehand.)
/// </summary>
/// <param name="forEach">The AST that represents the foreach loop</param>
/// <returns>Either whatever the base visitor returns or else null (if there is an error)</returns>
public override Statement VisitForEach(ForEach forEach) {
Statement s = base.VisitForEach(forEach);
ForEach f = s as ForEach;
if (f != null) {
// don't allow a source enumerable that is just an enumerator
CollectionEnumerator cEnumerator = f.SourceEnumerable as CollectionEnumerator;
if (cEnumerator != null && cEnumerator.GetEnumerator == null) {
// Then it is not a type that supports GetEnumerator(), but if it is an array, then we'll let it slide.
TypeNode possiblyArrayType = this.typeSystem.GetUnderlyingType(cEnumerator.Collection.Type) as ArrayType;
if (possiblyArrayType == null) {
this.HandleError(forEach,
Error.ForEachMissingMember,
this.GetTypeName(cEnumerator.Collection.Type),
this.GetTypeName(cEnumerator.Collection.Type),
"GetEnumerator");
return null;
}
}
}
return s;
}
public override Statement VisitForEach(ForEach forEach)
{
Normalizer normalizer = new Normalizer(false);
Identifier incrVar = new Identifier("____" + forEach.UniqueKey.ToString(CultureInfo.InvariantCulture));
Expression sourceEnumerable = normalizer.VisitExpression(forEach.SourceEnumerable);
Statement incrStmt = Templates.GetStatementTemplate("foreachIncrementer");
Replacer.Replace(incrStmt, "_iterator", incrVar);
BasicBlock incrBlock = new BasicBlock(incrStmt);
AddBlock(incrBlock);
incrBlock.MiddleOfTransition = true;
incrBlock.SkipNormalizer = true;
incrBlock.SourceContext = forEach.SourceContext;
PushContinuationStack(incrBlock);
this.Visit(forEach.Body);
BasicBlock bodyBlock = PopContinuationStack();
Statement derefStmt = Templates.GetStatementTemplate("foreachDeref");
Replacer.Replace(derefStmt, "_tmpVar",
normalizer.VisitExpression(forEach.TargetVariable));
Replacer.Replace(derefStmt, "_collectionExpr", sourceEnumerable);
Replacer.Replace(derefStmt, "_collectionType",
new Identifier(forEach.SourceEnumerable.Type.FullName));
Replacer.Replace(derefStmt, "_iterator", incrVar);
BasicBlock derefBlock = new BasicBlock(derefStmt, bodyBlock);
AddBlock(derefBlock);
derefBlock.MiddleOfTransition = true;
derefBlock.SkipNormalizer = true;
Expression testExpr = Templates.GetExpressionTemplate("foreachTest");
Replacer.Replace(testExpr, "_iterator", incrVar);
Replacer.Replace(testExpr, "_sourceEnumerable", sourceEnumerable);
BasicBlock testBlock = new BasicBlock(null, testExpr, derefBlock, CurrentContinuation);
AddBlock(testBlock);
testBlock.SkipNormalizer = true;
incrBlock.UnconditionalTarget = testBlock;
Statement initStmt = Templates.GetStatementTemplate("foreachInit");
Replacer.Replace(initStmt, "_iterator", incrVar);
BasicBlock initBlock = new BasicBlock(initStmt, testBlock);
AddBlock(initBlock);
initBlock.MiddleOfTransition = true;
initBlock.SkipNormalizer = true;
initBlock.SourceContext = forEach.SourceContext;
CurrentContinuation = initBlock;
return forEach;
}
//
// We support iteration over arrays and sets
//
public override Statement VisitForEach(ForEach forEach)
{
if (forEach == null) return null;
forEach.TargetVariableType = this.VisitTypeReference(forEach.TargetVariableType);
forEach.TargetVariable = this.VisitTargetExpression(forEach.TargetVariable);
forEach.SourceEnumerable = this.VisitExpression(forEach.SourceEnumerable);
if (forEach.TargetVariableType == null || forEach.TargetVariable == null || forEach.SourceEnumerable == null)
return null;
TypeNode collectionType = forEach.SourceEnumerable.Type;
Set setCollection = collectionType as Set;
ZArray arrayCollection = collectionType as ZArray;
TypeNode memberType = null;
if (setCollection != null)
memberType = setCollection.SetType;
if (arrayCollection != null)
memberType = arrayCollection.ElementType;
if (memberType == null)
{
this.HandleError(forEach.SourceEnumerable, Error.InvalidForeachSource);
return null;
}
if (memberType != forEach.TargetVariableType)
{
this.HandleError(forEach.TargetVariable, Error.InvalidForeachTargetType);
return null;
}
forEach.Body = this.VisitBlock(forEach.Body);
return forEach;
}
public EventingVisitor(Action<ForEach> visitForEach) { VisitedForEach += visitForEach; } public event Action<ForEach> VisitedForEach; public override Statement VisitForEach(ForEach forEach) { if (VisitedForEach != null) VisitedForEach(forEach); return base.VisitForEach(forEach); }
