3 * Implementation of GiNaC's parser. */
6 * GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
35 /// identifier_expr: identifier | identifier '(' expression* ')'
36 ex parser::parse_identifier_expr()
38 std::string name = scanner->str;
39 get_next_tok(); // eat identifier.
41 if (token != '(') // symbol
42 return find_or_insert_symbol(name, syms, strict);
44 // function/ctor call.
45 get_next_tok(); // eat (
49 ex e = parse_expression();
56 Parse_error("expected ')' or ',' in argument list");
63 prototype the_prototype = make_pair(name, args.size());
64 prototype_table::const_iterator reader = funcs.find(the_prototype);
65 if (reader == funcs.end()) {
66 Parse_error_("no function \"" << name << "\" with " <<
67 args.size() << " arguments");
69 // dirty hack to distinguish between serial numbers of functions and real
71 GiNaC::function* f = NULL;
73 unsigned serial = (unsigned)(unsigned long)(void *)(reader->second);
74 f = new GiNaC::function(serial, args);
76 catch ( std::runtime_error ) {
78 ex ret = reader->second(args);
81 return f->setflag(status_flags::dynallocated);
84 /// paren_expr: '(' expression ')'
85 ex parser::parse_paren_expr()
87 get_next_tok(); // eat (.
88 ex e = parse_expression();
91 Parse_error("expected ')'");
92 get_next_tok(); // eat ).
96 extern numeric* _num_1_p;
99 /// unary_expr: [+-] expression
100 ex parser::parse_unary_expr()
102 // Unlike most other parse_* method this one does NOT consume
103 // current token so parse_binop_rhs() knows what kind of operator
106 // There are different kinds of expressions which need to be handled:
111 // Delegete the work to parse_binop_rhs(), otherwise we end up
112 // duplicating it here.
113 ex lhs = _ex0; // silly trick
114 ex e = parse_binop_rhs(0, lhs);
118 /// primary: identifier_expr | number_expr | paren_expr | unary_expr
119 ex parser::parse_primary()
122 case lexer::token_type::identifier:
123 return parse_identifier_expr();
124 case lexer::token_type::number:
125 return parse_number_expr();
127 return parse_paren_expr();
130 return parse_unary_expr();
131 case lexer::token_type::literal:
132 return parse_literal_expr();
133 case lexer::token_type::eof:
135 Parse_error("unexpected token");
139 /// expression ::= primary binoprhs
140 ex parser::parse_expression()
142 ex lhs = parse_primary();
143 ex res = parse_binop_rhs(0, lhs);
147 /// number_expr: number
148 ex parser::parse_number_expr()
150 ex n = numeric(scanner->str.c_str());
151 get_next_tok(); // consume the number
155 /// literal_expr: 'I' | 'Pi' | 'Euler' | 'Catalan'
156 ex parser::parse_literal_expr()
158 get_next_tok(); // consume the literal
159 if (scanner->str == "I")
161 else if (scanner->str == "Pi")
163 else if (scanner->str == "Euler")
165 else if (scanner->str == "Catalan")
167 bug("unknown literal: \"" << scanner->str << "\"");
170 ex parser::operator()(std::istream& input)
172 scanner->switch_input(&input);
174 ex ret = parse_expression();
175 // parse_expression() stops if it encounters an unknown token.
176 // This is not a bug: since the parser is recursive checking
177 // whether the next token is valid is responsibility of the caller.
178 // Hence make sure nothing is left in the stream:
179 if (token != lexer::token_type::eof)
180 Parse_error("expected EOF");
185 ex parser::operator()(const std::string& input)
187 std::istringstream is(input);
188 ex ret = operator()(is);
192 int parser::get_next_tok()
194 token = scanner->gettok();
198 parser::parser(const symtab& syms_, const bool strict_,
199 const prototype_table& funcs_) : strict(strict_),
200 funcs(funcs_), syms(syms_)
202 scanner = new lexer();