/// <summary>
/// Analyses the tokens to produce an AST of Expr.
/// When <paramref name="allowGlobalUse"/> is true and <see cref="Config.GlobalScope"/> is true, the top-level declarations
/// go into the global scope.
/// </summary>
/// <param name="p">Tokeinzer to analyse.</param>
/// <param name="allowGlobalUse">False to scope declarations to this analysis.</param>
/// <returns>The AST (that may be a <see cref="SyntaxErrorExpr"/> or contains such errors).</returns>
public Expr Analyse(JSTokenizer p, bool allowGlobalUse = true)
{
_parser = p;
if (!(allowGlobalUse && _scope.GlobalScope))
{
_scope.OpenScope();
}
return(HandleBlock(Expression(0)));
}
Expr HandleAssign(Expr left, bool pureAssign = false)
{
var location = _parser.Location;
AccessorExpr a = left as AccessorExpr;
if (a == null)
{
return(new SyntaxErrorExpr(location, "Invalid assignment left-hand side."));
}
if (pureAssign || _parser.Match(JSTokenizerToken.Assign))
{
return(new AssignExpr(location, a, Expression(JSTokenizer.PrecedenceLevel(JSTokenizerToken.Comma))));
}
JSTokenizerToken binaryTokenType = JSTokenizer.FromAssignOperatorToBinary(_parser.CurrentToken);
_parser.Forward();
return(new AssignExpr(location, a, new BinaryExpr(location, left, binaryTokenType, Expression(0))));
}
Expr HandleUnaryExpr()
{
var loc = _parser.Location;
var t = _parser.CurrentToken;
_parser.Forward();
// Unary operators are JSTokenizerToken.OpLevel14, except Minus and Plus that are classified as binary operators and are associated to OpLevel12.
var right = Expression(JSTokenizer.PrecedenceLevel(JSTokenizerToken.OpLevel14));
if (t == JSTokenizerToken.PlusPlus || t == JSTokenizerToken.MinusMinus)
{
AccessorExpr a = right as AccessorExpr;
if (a == null)
{
return(new SyntaxErrorExpr(loc, "invalid increment operand."));
}
return(new PrePostIncDecExpr(loc, a, t == JSTokenizerToken.PlusPlus, true, right.IsStatement));
}
return(new UnaryExpr(loc, t, right));
}
Expr HandleCall(Expr left)
{
SourceLocation loc = _parser.PrevNonCommentLocation;
IList <Expr> parameters = null;
if (!_parser.Match(JSTokenizerToken.ClosePar))
{
for ( ; ;)
{
Debug.Assert(JSTokenizer.PrecedenceLevel(JSTokenizerToken.Comma) == 2);
Expr e = Expression(2);
if (e is SyntaxErrorExpr)
{
return(e);
}
if (parameters == null)
{
parameters = new List <Expr>();
}
parameters.Add(e);
if (_parser.Match(JSTokenizerToken.ClosePar))
{
break;
}
if (!_parser.Match(JSTokenizerToken.Comma))
{
return(new SyntaxErrorExpr(_parser.Location, "Expected ) opened at {0}.", loc));
}
}
}
var arguments = parameters != null?parameters.ToArray() : Expr.EmptyArray;
return(new AccessorCallExpr(loc, left, arguments, _parser.Match(JSTokenizerToken.SemiColon)));
}
NotImplementedException UnsupportedOperatorException()
{
string msg = String.Format("Unsupported binary operator: '{0}' ({1}).", JSTokenizer.Explain(Expr.BinaryOperatorToken), (int)Expr.BinaryOperatorToken);
return(new NotImplementedException(msg));
}
/// <summary>
/// This is just to ease debugging.
/// </summary>
/// <returns>Readable expression.</returns>
public override string ToString()
{
return(Left.ToString() + JSTokenizer.Explain(BinaryOperatorToken) + Right.ToString());
}
public override string ToString()
{
return(JSTokenizer.Explain(TokenType) + Expression.ToString());
}
Expr HandleLogicalExpr(Expr left)
{
_parser.Forward();
// Right associative operators to support short-circuit (hence the -1 on the level).
return(new BinaryExpr(_parser.PrevNonCommentLocation, left, _parser.PrevNonCommentToken, Expression(JSTokenizer.PrecedenceLevel(_parser.PrevNonCommentToken) - 1)));
}
Expr HandleBinaryExpr(Expr left)
{
_parser.Forward();
return(new BinaryExpr(_parser.PrevNonCommentLocation, left, _parser.PrevNonCommentToken, Expression(JSTokenizer.PrecedenceLevel(_parser.PrevNonCommentToken))));
}
NotSupportedException UnsupportedOperatorException()
{
string msg = String.Format("Unsupported unary operator: '{0}' ({1}).", JSTokenizer.Explain(Expr.TokenType), (int)Expr.TokenType);
return(new NotSupportedException(msg));
}
