/// <summary>
/// Create a new block argument.
/// </summary>
/// <param name="parent">Block closure that defines the argument node.</param>
/// <param name="colon">Colon that preceeds the argument name.</param>
/// <param name="token">Identifier token containing the name of the argument.</param>
protected internal BlockArgumentNode(BlockNode parent, SpecialCharacterToken colon, IdentifierToken token)
: base(token)
{
#if DEBUG
if (parent == null)
throw new ArgumentNullException("parent");
if (colon == null)
throw new ArgumentNullException("colon");
#endif
this.Colon = colon;
this.Parent = parent;
}
/// <summary>
/// Create a new block argument.
/// </summary>
/// <param name="parent">Block closure that defines the argument node.</param>
/// <param name="colon">Colon that precedes the argument name.</param>
/// <param name="token">Identifier token containing the name of the argument.</param>
protected internal BlockArgumentNode(BlockNode parent, SpecialCharacterToken colon, IdentifierToken token)
: base(token)
{
#if DEBUG
if (parent == null)
{
throw new ArgumentNullException("parent");
}
if (colon == null)
{
throw new ArgumentNullException("colon");
}
#endif
this.Colon = colon;
this.Parent = parent;
}
protected virtual BlockArgumentNode ParseBlockArgument(BlockNode parent, SpecialCharacterToken colon)
{
// PARSE: <block argument> ::= ':' identifier
Token token = this.GetNextTokenxx(Preference.Default);
if (!(token is IdentifierToken))
{
this.ReportParserError(parent, SemanticErrors.MissingBlockArgument, token);
this.ResidueToken = token;
// NB: BlockArgumentNode must be able to handle null for arg. name token.
return new BlockArgumentNode(parent, colon, null);
}
return new BlockArgumentNode(parent, colon, (IdentifierToken)token);
}
protected virtual BlockNode ParseBlock(IPrimaryParentNode parent, SpecialCharacterToken leftBracket)
{
// PARSE: <block constructor> ::= '[' <block body> ']'
// <block body> ::= [<block argument>* '|'] [<temporaries>] [<statements>]
// <block argument> ::= ':' identifier
BlockNode result = new BlockNode(parent, leftBracket);
// PARSE: [<block argument>* '|']
// ISSUE: It this a bug in X3J20. Shouldn't it be: [<block argument>+ '|']
// The current definition allows blocks like: [ | ] ... or ... [ | self doStuff ] ... or ... [ | | temp | temp := self something ]
// We assume X3J20 bug and expect: [<block argument>+ '|']
VerticalBarToken argumentsBar = null;
List<BlockArgumentNode> arguments = new List<BlockArgumentNode>();
Token token = this.GetNextTokenxx(Preference.VerticalBar | Preference.NegativeSign);
// Check if the block has arguments
if (Parser.IsBlockArgumentPrefix(token))
{
// ... yes arguments ... parse them ...
while (true)
{
if (Parser.IsBlockArgumentPrefix(token))
{
// <block argument>
arguments.Add(this.ParseBlockArgument(result, (SpecialCharacterToken)token));
}
else if (token is VerticalBarToken)
{
// The '|' after the arguments.
argumentsBar = (VerticalBarToken)token;
token = this.GetNextTokenxx(Preference.NegativeSign | Preference.VerticalBar);
break; // Done with block arguments
}
else
{
this.ReportParserError(result, SemanticErrors.MissingBlockClosingArgsBar, token);
break;
}
// Get the next token
token = this.GetNextTokenxx(Preference.VerticalBar | Preference.NegativeSign);
}
}
// PARSE: [<temporaries>]
ParseTemporariesResult ptr = this.ParseTemporaries(result, token);
// PARSE: <statements>
token = this.GetNextTokenxx(Preference.NegativeSign);
StatementNode statements = this.ParseStatement(result, token);
// Ensure the block is properly closed.
SpecialCharacterToken rightBracket = null;
token = this.GetNextTokenxx(Preference.Default) ;
if (!Parser.IsBlockEndDelimiter(token))
{
this.ReportParserError(result, SemanticErrors.MissingBlockClosingBracket, token);
this.ResidueToken = token;
}
else
{
rightBracket = (SpecialCharacterToken)token;
}
result.SetContents(arguments, argumentsBar, ptr.LeftBar, ptr.Temporaries, ptr.RightBar, statements, rightBracket);
return result;
}