VariableVisit IVariableVisitor <VariableVisit> .Visit(Variable.Identifier variable)
{
return(VariableVisit.CreateIdentifier(variable.Value));
}
/* Parses prefixExpression
* variable | functionCall | '(' expression ')' */
PrefixExpression PrefixExpression()
{
/* prefixexpr -> NAME | '(' expr ')' */
// Parse the terminal/first symbol of the prefixExpression
PrefixExpression left;
switch (Current.Symbol)
{
case Symbol.LeftParen:
var leftSpan = Expect(Symbol.LeftParen).Span;
var expr = Expression();
var rightSpan = ExpectMatch(Symbol.RightParen, Symbol.LeftParen, leftSpan.Start).Span;
left = new PrefixExpression.Expression(expr, new SourceSpan(leftSpan.Start, rightSpan.End));
break;
case Symbol.Identifier:
var identifier = Consume();
var idVar = new Variable.Identifier(identifier.Lexeme) { Span = identifier.Span };
left = new PrefixExpression.Variable(idVar);
break;
default:
throw ReportSyntaxErrorNear("unexpected symbol");
}
/* primaryexpr -> prefixexpr { `.' NAME | `[' expr `]' | `:' NAME funcargs | funcargs } */
while (true)
{
Token identifier;
switch (Current.Symbol)
{
case Symbol.LeftBrack:
var leftSpan = Expect(Symbol.LeftBrack).Span;
var expr = Expression();
var rightSpan = ExpectMatch(Symbol.RightBrack, Symbol.LeftBrack, leftSpan.Start).Span;
var memberExpr = new Variable.MemberExpr(left, expr)
{
Span = new SourceSpan(left.Span.Start, rightSpan.End)
};
left = new PrefixExpression.Variable(memberExpr);
break;
case Symbol.Dot:
Consume();
identifier = Expect(Symbol.Identifier);
var memberId = new Variable.MemberId(left, identifier.Lexeme)
{
Span = new SourceSpan(left.Span.Start, identifier.Span.End)
};
left = new PrefixExpression.Variable(memberId);
break;
case Symbol.Colon:
Consume();
identifier = Expect(Symbol.Identifier);
var arguments = Arguments();
left = new PrefixExpression.FunctionCall(new FunctionCall.Table(left, identifier.Lexeme, arguments)
{
Span = new SourceSpan(left.Span.Start, arguments.Span.End)
});
break;
case Symbol.LeftParen:
case Symbol.LeftBrace:
case Symbol.String:
var args = Arguments();
left = new PrefixExpression.FunctionCall(new FunctionCall.Normal(left, args)
{
Span = new SourceSpan(left.Span.Start, args.Span.End)
});
break;
// Unrecognized symbol, return what we have so far
default:
return left;
}
}
}
