3 * Implementation of GiNaC's parser. */
6 * GiNaC Copyright (C) 1999-2015 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 #include <stdint.h> // for uintptr_t
43 // Find out if ptr is a pointer to a function or a specially crafted integer.
44 // It's possible to distinguish between these because functions are aligned.
45 // Returns true if ptr is a pointer and false otherwise.
46 static bool decode_serial(unsigned& serial, const reader_func ptr)
48 uintptr_t u = (uintptr_t)(void *)ptr;
57 // Figures out if ptr is a pointer to function or a serial of GiNaC function.
58 // In the former case calls that function, in the latter case constructs
59 // GiNaC function with corresponding serial and arguments.
60 static ex dispatch_reader_fcn(const reader_func ptr, const exvector& args)
62 unsigned serial = 0; // dear gcc, could you please shut up?
63 bool is_ptr = decode_serial(serial, ptr);
67 return function(serial, args);
72 /// identifier_expr: identifier | identifier '(' expression* ')'
73 ex parser::parse_identifier_expr()
75 std::string name = scanner->str;
76 get_next_tok(); // eat identifier.
78 if (token != '(') // symbol
79 return find_or_insert_symbol(name, syms, strict);
81 // function/ctor call.
82 get_next_tok(); // eat (
86 ex e = parse_expression();
93 Parse_error("expected ')' or ',' in argument list");
100 prototype the_prototype = make_pair(name, args.size());
101 prototype_table::const_iterator reader = funcs.find(the_prototype);
102 if (reader == funcs.end()) {
103 Parse_error_("no function \"" << name << "\" with " <<
104 args.size() << " arguments");
106 // reader->second might be a pointer to a C++ function or a specially
107 // crafted serial of a GiNaC::function.
108 ex ret = dispatch_reader_fcn(reader->second, args);
112 /// paren_expr: '(' expression ')'
113 ex parser::parse_paren_expr()
115 get_next_tok(); // eat (.
116 ex e = parse_expression();
119 Parse_error("expected ')'");
120 get_next_tok(); // eat ).
124 /// lst_expr: '{' expression { ',' expression } '}'
125 ex parser::parse_lst_expr()
127 get_next_tok(); // eat {.
132 ex e = parse_expression(); // expression();
140 Parse_error("expected '}'");
143 get_next_tok(); // eat ','.
152 extern const ex _ex0;
154 /// unary_expr: [+-] expression
155 ex parser::parse_unary_expr()
157 // Unlike most other parse_* method this one does NOT consume
158 // current token so parse_binop_rhs() knows what kind of operator
161 // There are different kinds of expressions which need to be handled:
166 // Delegete the work to parse_binop_rhs(), otherwise we end up
167 // duplicating it here.
168 ex lhs = _ex0; // silly trick
169 ex e = parse_binop_rhs(0, lhs);
173 /// primary: identifier_expr | number_expr | paren_expr | unary_expr
174 ex parser::parse_primary()
177 case lexer::token_type::identifier:
178 return parse_identifier_expr();
179 case lexer::token_type::number:
180 return parse_number_expr();
182 return parse_paren_expr();
184 return parse_lst_expr();
187 return parse_unary_expr();
188 case lexer::token_type::literal:
189 return parse_literal_expr();
190 case lexer::token_type::eof:
192 Parse_error("unexpected token");
196 /// expression ::= primary binoprhs
197 ex parser::parse_expression()
199 ex lhs = parse_primary();
200 ex res = parse_binop_rhs(0, lhs);
204 /// number_expr: number
205 ex parser::parse_number_expr()
207 ex n = numeric(scanner->str.c_str());
208 get_next_tok(); // consume the number
212 /// literal_expr: 'I' | 'Pi' | 'Euler' | 'Catalan'
213 ex parser::parse_literal_expr()
215 get_next_tok(); // consume the literal
216 if (scanner->str == "I")
218 else if (scanner->str == "Pi")
220 else if (scanner->str == "Euler")
222 else if (scanner->str == "Catalan")
224 bug("unknown literal: \"" << scanner->str << "\"");
227 ex parser::operator()(std::istream& input)
229 scanner->switch_input(&input);
231 ex ret = parse_expression();
232 // parse_expression() stops if it encounters an unknown token.
233 // This is not a bug: since the parser is recursive checking
234 // whether the next token is valid is responsibility of the caller.
235 // Hence make sure nothing is left in the stream:
236 if (token != lexer::token_type::eof)
237 Parse_error("expected EOF");
242 ex parser::operator()(const std::string& input)
244 std::istringstream is(input);
245 ex ret = operator()(is);
249 int parser::get_next_tok()
251 token = scanner->gettok();
255 parser::parser(const symtab& syms_, const bool strict_,
256 const prototype_table& funcs_) : strict(strict_),
257 funcs(funcs_), syms(syms_)
259 scanner = new lexer();