}
extern numeric* _num_1_p;
+extern ex _ex0;
/// unary_expr: [+-] expression
-ex parser::parse_unary_expr(const int s)
+ex parser::parse_unary_expr()
{
- // consume '-' (or '+')
- get_next_tok();
- ex v = parse_expression();
- switch (s) {
- case '-':
- return (new mul(v, *_num_1_p))->setflag(status_flags::dynallocated);
- case '+':
- return v;
- default:
- Parse_error_("invalid unary operator \"" << char(s) << "\"");
- }
+ // Unlike most other parse_* method this one does NOT consume
+ // current token so parse_binop_rhs() knows what kind of operator
+ // is being parsed.
+
+ // There are different kinds of expressions which need to be handled:
+ // -a+b
+ // -(a)
+ // +a
+ // +(a)
+ // Delegete the work to parse_binop_rhs(), otherwise we end up
+ // duplicating it here.
+ ex lhs = _ex0; // silly trick
+ ex e = parse_binop_rhs(0, lhs);
+ return e;
}
/// primary: identifier_expr | number_expr | paren_expr | unary_expr
case '(':
return parse_paren_expr();
case '-':
- return parse_unary_expr('-');
case '+':
- return parse_unary_expr('+');
+ return parse_unary_expr();
case lexer::token_type::literal:
return parse_literal_expr();
case lexer::token_type::eof:
/// literal_expr: 'I' | 'Pi' | 'Euler' | 'Catalan'
ex parser::parse_literal_expr()
{
+ get_next_tok(); // consume the literal
if (scanner->str == "I")
return I;
else if (scanner->str == "Pi")
return token;
}
-parser::parser(const symtab& syms_, const prototype_table& funcs_,
- const bool strict_) : strict(strict_), funcs(funcs_),
- syms(syms_)
+parser::parser(const symtab& syms_, const bool strict_,
+ const prototype_table& funcs_) : strict(strict_),
+ funcs(funcs_), syms(syms_)
{
scanner = new lexer();
}