public virtual ComprehensionBinding VisitComprehensionBinding(ComprehensionBinding comprehensionBinding)
{
if (comprehensionBinding == null) return null;
comprehensionBinding.TargetVariableType = this.VisitTypeReference(comprehensionBinding.TargetVariableType);
comprehensionBinding.TargetVariable = this.VisitTargetExpression(comprehensionBinding.TargetVariable);
comprehensionBinding.AsTargetVariableType = this.VisitTypeReference(comprehensionBinding.AsTargetVariableType);
comprehensionBinding.SourceEnumerable = this.VisitExpression(comprehensionBinding.SourceEnumerable);
return comprehensionBinding;
}
private Expression ParseIteratorOrExpression( TokenSet followers ) {
SourceContext sctx = this.scanner.CurrentSourceContext;
ScannerState ss = this.scanner.state;
// shortcut for ( <expression>)
if( this.currentToken == Token.LeftParenthesis ) {
// then it can't be a binding, it must be a filter.
Expression e = ParseExpression(followers );
e.SourceContext = sctx;
e.SourceContext.EndPos = this.scanner.CurrentSourceContext.StartPos;
return e;
}
// try fully formed syntax: <type> <name> in <expression>
ComprehensionBinding q = new ComprehensionBinding();
q.TargetVariableType = q.TargetVariableTypeExpression = this.ParseTypeExpression(null,
followers | Parser.IdentifierOrNonReservedKeyword |Token.In|Token.RightBrace|Token.Semicolon|Token.Comma, true );
if (q.TargetVariableType != null && Parser.IdentifierOrNonReservedKeyword[this.currentToken] ) {
q.TargetVariable = this.scanner.GetIdentifier();
q.SourceContext = this.scanner.CurrentSourceContext;
this.SkipIdentifierOrNonReservedKeyword();
// after the identifier, look for 'in' keyword
if( this.currentToken == Token.In ) {
this.Skip(Token.In);
q.SourceEnumerable = this.ParseExpression(followers);
q.SourceContext = sctx;
q.SourceContext.EndPos = this.scanner.CurrentSourceContext.StartPos;
return q;
}
}
// back up and try as untyped iterator: <name> in <expression>
q.TargetVariableType = q.TargetVariableTypeExpression = null;
this.scanner.endPos = sctx.StartPos;
this.scanner.state = ss;
this.currentToken = Token.None;
this.GetNextToken();
if (Parser.IdentifierOrNonReservedKeyword[this.currentToken] ) {
q.TargetVariable = this.scanner.GetIdentifier();
q.SourceContext = this.scanner.CurrentSourceContext;
this.SkipIdentifierOrNonReservedKeyword();
// after the identifier, look for 'in' keyword
if( this.currentToken == Token.In ) {
this.Skip(Token.In);
q.SourceEnumerable = this.ParseExpression(followers);
return q;
} else if (this.currentToken == Token.As) {
this.Skip(Token.As);
q.AsTargetVariableType = q.AsTargetVariableTypeExpression = this.ParseTypeExpression(null,
followers|Token.In|Token.RightBrace|Token.Semicolon|Token.Comma, false);
this.Skip(Token.In);
q.SourceEnumerable = this.ParseExpression(followers);
return q;
}
}
// back up and try as unnamed expression: <expression>
this.scanner.endPos = sctx.StartPos;
this.scanner.state = ss;
this.currentToken = Token.None;
this.GetNextToken();
return this.ParseExpression(followers);
}
public override ComprehensionBinding VisitComprehensionBinding(ComprehensionBinding comprehensionBinding)
{
if (comprehensionBinding == null) return null;
return base.VisitComprehensionBinding((ComprehensionBinding)comprehensionBinding.Clone());
}
public EventingVisitor(Action<ComprehensionBinding> visitComprehensionBinding) { VisitedComprehensionBinding += visitComprehensionBinding; } public event Action<ComprehensionBinding> VisitedComprehensionBinding; public override ComprehensionBinding VisitComprehensionBinding(ComprehensionBinding comprehensionBinding) { if (VisitedComprehensionBinding != null) VisitedComprehensionBinding(comprehensionBinding); return base.VisitComprehensionBinding(comprehensionBinding); }
