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
36 // Find out if ptr is a pointer to a function or a specially crafted integer.
37 // It's possible to distinguish between these because functions are aligned.
38 // Returns true if ptr is a pointer and false otherwise.
39 static bool decode_serial(unsigned& serial, const reader_func ptr)
41 uintptr_t u = (uintptr_t)(void *)ptr;
50 // Figures out if ptr is a pointer to function or a serial of GiNaC function.
51 // In the former case calls that function, in the latter case constructs
52 // GiNaC function with corresponding serial and arguments.
53 static ex dispatch_reader_fcn(const reader_func ptr, const exvector& args)
55 unsigned serial = 0; // dear gcc, could you please shut up?
56 bool is_ptr = decode_serial(serial, ptr);
60 return function(serial, args);
65 /// identifier_expr: identifier | identifier '(' expression* ')'
66 ex parser::parse_identifier_expr()
68 std::string name = scanner->str;
69 get_next_tok(); // eat identifier.
71 if (token != '(') // symbol
72 return find_or_insert_symbol(name, syms, strict);
74 // function/ctor call.
75 get_next_tok(); // eat (
79 ex e = parse_expression();
86 Parse_error("expected ')' or ',' in argument list");
93 prototype the_prototype = make_pair(name, args.size());
94 prototype_table::const_iterator reader = funcs.find(the_prototype);
95 if (reader == funcs.end()) {
96 Parse_error_("no function \"" << name << "\" with " <<
97 args.size() << " arguments");
99 // reader->second might be a pointer to a C++ function or a specially
100 // crafted serial of a GiNaC::function.
101 ex ret = dispatch_reader_fcn(reader->second, args);
105 /// paren_expr: '(' expression ')'
106 ex parser::parse_paren_expr()
108 get_next_tok(); // eat (.
109 ex e = parse_expression();
112 Parse_error("expected ')'");
113 get_next_tok(); // eat ).
117 extern numeric* _num_1_p;
120 /// unary_expr: [+-] expression
121 ex parser::parse_unary_expr()
123 // Unlike most other parse_* method this one does NOT consume
124 // current token so parse_binop_rhs() knows what kind of operator
127 // There are different kinds of expressions which need to be handled:
132 // Delegete the work to parse_binop_rhs(), otherwise we end up
133 // duplicating it here.
134 ex lhs = _ex0; // silly trick
135 ex e = parse_binop_rhs(0, lhs);
139 /// primary: identifier_expr | number_expr | paren_expr | unary_expr
140 ex parser::parse_primary()
143 case lexer::token_type::identifier:
144 return parse_identifier_expr();
145 case lexer::token_type::number:
146 return parse_number_expr();
148 return parse_paren_expr();
151 return parse_unary_expr();
152 case lexer::token_type::literal:
153 return parse_literal_expr();
154 case lexer::token_type::eof:
156 Parse_error("unexpected token");
160 /// expression ::= primary binoprhs
161 ex parser::parse_expression()
163 ex lhs = parse_primary();
164 ex res = parse_binop_rhs(0, lhs);
168 /// number_expr: number
169 ex parser::parse_number_expr()
171 ex n = numeric(scanner->str.c_str());
172 get_next_tok(); // consume the number
176 /// literal_expr: 'I' | 'Pi' | 'Euler' | 'Catalan'
177 ex parser::parse_literal_expr()
179 get_next_tok(); // consume the literal
180 if (scanner->str == "I")
182 else if (scanner->str == "Pi")
184 else if (scanner->str == "Euler")
186 else if (scanner->str == "Catalan")
188 bug("unknown literal: \"" << scanner->str << "\"");
191 ex parser::operator()(std::istream& input)
193 scanner->switch_input(&input);
195 ex ret = parse_expression();
196 // parse_expression() stops if it encounters an unknown token.
197 // This is not a bug: since the parser is recursive checking
198 // whether the next token is valid is responsibility of the caller.
199 // Hence make sure nothing is left in the stream:
200 if (token != lexer::token_type::eof)
201 Parse_error("expected EOF");
206 ex parser::operator()(const std::string& input)
208 std::istringstream is(input);
209 ex ret = operator()(is);
213 int parser::get_next_tok()
215 token = scanner->gettok();
219 parser::parser(const symtab& syms_, const bool strict_,
220 const prototype_table& funcs_) : strict(strict_),
221 funcs(funcs_), syms(syms_)
223 scanner = new lexer();