// AssignExpr
public virtual bool Walk(AssignExpr node) { return true; }
public virtual void PostWalk(AssignExpr node) { }
public override void PostWalk(AssignExpr node) { }
// AssignExpr
public override bool Walk(AssignExpr node) { return false; }
private Expr ParseAssignmentExpr()
{
Expr ret = ParseConditionalExpr();
if (ret == null)
return ret;
while (IsAssignToken(PeekToken()))
{
string assignError = ret.CheckAssign();
if (assignError != null)
{
ReportSyntaxError(ret.StartIndex, ret.EndIndex, assignError, ErrorCodes.SyntaxError);
}
var token = NextToken();
var start = ret.StartIndex;
ret = new AssignExpr(token.Kind, ret, ParseConditionalExpr());
}
return ret;
}
private Expr ParsePrimaryExpr()
{
int start, end, globalStart;
Expr ret;
// lambda handling
List<Parameter> parameters = new List<Parameter>();
Parameter param;
bool startBody = false;
switch (PeekToken().Kind)
{
case TokenType.Name:
NameToken nameToken = (NameToken)NextToken();
globalStart = GetStart();
if (_sink != null)
_sink.StartName(GetSourceSpan(), nameToken.Name);
ret = new IdentifierExpr(nameToken.Name);
ret.SetLoc(_globalParent, GetStart(), GetEnd());
if (MaybeEat(TokenType.Arrow))
{
param = new Parameter(nameToken.Name);
param.SetLoc(_globalParent, ret.IndexSpan);
parameters.Add(param);
startBody = true;
goto lambda;
}
return ret;
case TokenType.Constant:
ConstantValueToken constantToken = (ConstantValueToken)NextToken();
start = GetStart();
object cv = constantToken.Value;
if (cv == null)
{
ret = new ConstantExpr(null);
}
else if (cv is bool)
{
ret = new ConstantExpr((bool)cv);
}
else if (cv is string)
{
ret = new ConstantExpr((string)cv);
}
else if (cv is int)
{
ret = new ConstantExpr((int)cv);
}
else if (cv is Uninitialized)
{
ret = new ConstantExpr(Uninitialized.Instance);
}
else if (cv is double)
{
ret = new ConstantExpr((double)cv);
}
else if (cv is BigInteger)
{
ret = new ConstantExpr((BigInteger)cv);
}
else
{
throw Assert.Unreachable;
}
ret.SetLoc(_globalParent, GetStart(), GetEnd());
return ret;
case TokenType.LeftParenthesis:
NextToken();
start = GetStart();
globalStart = GetStart();
if (PeekToken().Kind == TokenType.Name) // may be lambda: (a = 2) => a;
{
NameToken nt = (NameToken)NextToken();
if (PeekToken().Kind == TokenType.RightParenthesis)
{
end = GetEnd();
start = GetStart();
NextToken();
if (MaybeEat(TokenType.Arrow))
{
param = new Parameter(nt.Name);
param.SetLoc(_globalParent, GetStart(), end);
parameters.Add(param);
startBody = true;
goto lambda;
}
else
{
ret = new IdentifierExpr(nt.Name);
ret.SetLoc(_globalParent, start, end);
ret = new ParenthesisExpr(ret);
ret.SetLoc(_globalParent, globalStart, GetEnd());
return ret;
}
}
else if (PeekToken().Kind == TokenType.Assign)
{
end = GetEnd();
start = GetStart();
NextToken();
var left = new IdentifierExpr(nt.Name);
left.SetLoc(_globalParent, start, end);
var right = ParseExpr();
if (PeekToken().Kind == TokenType.RightParenthesis)
{
end = GetEnd();
NextToken();
if (MaybeEat(TokenType.Arrow))
{
param = new Parameter(nt.Name, right);
param.SetLoc(_globalParent, left.StartIndex, right.EndIndex);
parameters.Add(param);
startBody = true;
goto lambda;
}
else
{
ret = new AssignExpr(TokenType.Assign, left, right);
ret.SetLoc(_globalParent, start, end);
ret = new ParenthesisExpr(ret);
ret.SetLoc(_globalParent, globalStart, GetEnd());
return ret;
}
}
else if (PeekToken().Kind == TokenType.Comma)
{
param = new Parameter(nt.Name, right);
param.SetLoc(_globalParent, start, GetEnd());
parameters.Add(param);
goto lambda;
}
else
{
throw Assert.Unreachable;
}
}
else if (PeekToken().Kind == TokenType.Comma)
{
param = new Parameter(nt.Name);
param.SetLoc(_globalParent, GetStart(), GetEnd());
parameters.Add(param);
goto lambda;
}
else
{
throw Assert.Unreachable;
}
}
else if (PeekToken(TokenType.RightParenthesis))
{
goto lambda;
}
else // not NameToken nor RightParen
{
ret = new ParenthesisExpr(ParseExpr());
Eat(TokenType.RightParenthesis);
ret.SetLoc(_globalParent, globalStart, GetEnd());
return ret;
}
lambda: // parse the rest of the lambda
if (!startBody)
{
while (MaybeEat(TokenType.Comma))
{
if (PeekToken(TokenType.Name))
throw new SyntaxErrorException();
NameToken nt = (NameToken)NextToken();
start = GetStart();
Expr defaultVal = MaybeEat(TokenType.Assign) ? ParseExpr() : null;
param = new Parameter(nt.Name, defaultVal);
param.SetLoc(_globalParent, start, GetEnd());
parameters.Add(param);
}
Eat(TokenType.RightParenthesis);
Eat(TokenType.Arrow);
}
return ParseLambdaBody(globalStart, parameters.ToArray());
case TokenType.LeftBracket:
return ParseArrayLiteral();
default:
return null; // syntax error
}
}
// AssignExpr
public override bool Walk(AssignExpr node)
{
node.Parent = _currentScope;
return base.Walk(node);
}