/// <summary>
///
/// Unary syntax:
/// Unary -> UnaryOperator* Term ( ASTStructInitializer | ASTEmptyInitializer | ASTEmptyInitializer | ASTCall | ASTIndexing )*
/// ASTStructInitializer -> "{" ( Identifier "=" Expression )* "}"
/// ASTArrayInitializer -> "{" Expression+ "}"
/// ASTEmptyInitializer -> "{" "}"
/// ASTCall -> "(" ( Expression ( "," Expression )* )? ")"
/// ASTIndexing -> "[" ( Expression ( "," Expression )* )? "]"
///
/// </summary>
/// <returns></returns>
private ASTNode ParseUnary()
{
(ASTUnaryNode top, ASTUnaryNode leaf) GetPrefix()
{
if (!EatToken(IsUnaryOperator))
{
return(null, null);
}
var unaryTop = MakeUnaryOperator(EatenToken);
var(child, unaryLeaf) = GetPrefix();
unaryTop.Child = child;
if (unaryLeaf == null)
{
unaryLeaf = unaryTop;
}
return(unaryTop, unaryLeaf);
}
(ASTNode top, ASTUnaryNode leaf) = GetPrefix();
var term = ParseTerm();
if (term == null)
{
return(null);
}
if (top == null)
{
top = term;
}
else
{
leaf.Child = term;
}
while (EatToken(t => t == TokenKind.CurlyLeft ||
t == TokenKind.ParenthesesLeft ||
t == TokenKind.SquareLeft))
{
if (EatenToken.Kind == TokenKind.CurlyLeft)
{
// ASTStructInitializer -> "{" ( Identifier "=" Expression )+ "}"
if (PeekTokenIs(TokenKind.Identifier) && PeekTokenIs(TokenKind.Equal, 1))
{
ASTAssign ParseInitialized()
{
var ident = PeekToken();
if (!Expect(TokenKind.Identifier))
{
return(null);
}
if (!Expect(TokenKind.Equal))
{
return(null);
}
var right = ParseExpression();
if (right == null)
{
return(null);
}
return(new ASTAssign(null)
{
Left = new ASTSymbol(ident.Position, ident.Value),
Right = right
});
}
var equals = ParseMany(TokenKind.CurlyRight, ParseInitialized);
if (equals == null)
{
return(null);
}
top = new ASTStructInitializer(top.Position)
{
Child = top, Values = equals
};
}
// ASTArrayInitializer -> "{" Expression+ "}"
// ASTEmptyInitializer -> "{" "}"
else
{
var values = ParseMany(TokenKind.CurlyRight, ParseExpression);
if (values == null)
{
return(null);
}
if (values.Any())
{
top = new ASTArrayInitializer(top.Position)
{
Child = top, Values = values
}
}
;
else
{
top = new ASTEmptyInitializer(top.Position)
{
Child = top
}
};
}
}
// ASTIndexing -> "[" ( Expression ( "," Expression )* )? "]"
// ASTCall -> "(" ( Expression ( "," Expression )* )? ")"
else
{
var last = EatenToken.Kind == TokenKind.ParenthesesLeft
? TokenKind.ParenthesesRight
: TokenKind.SquareRight;
var arguments = ParseMany(last, TokenKind.Comma, ParseExpression);
if (arguments == null)
{
return(null);
}
top = EatenToken.Kind == TokenKind.ParenthesesRight
? (ASTNode) new ASTCall(top.Position)
{
Child = top, Arguments = arguments
}
: (ASTNode) new ASTIndexing(top.Position)
{
Child = top, Arguments = arguments
};
}
}
return(top);
}
// TODO: Implement later
protected override bool Visit(ASTStructInitializer node)
{
throw new NotImplementedException();
}
protected abstract bool Visit(ASTStructInitializer node);