3 * Implementation of GiNaC's parser. */
6 * GiNaC Copyright (C) 1999-2019 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
31 #include <cstdint> // for uintptr_t
38 // Find out if ptr is a pointer to a function or a specially crafted integer.
39 // It's possible to distinguish between these because functions are aligned.
40 // Returns true if ptr is a pointer and false otherwise.
41 static bool decode_serial(unsigned& serial, const reader_func ptr)
43 uintptr_t u = (uintptr_t)(void *)ptr;
52 // Figures out if ptr is a pointer to function or a serial of GiNaC function.
53 // In the former case calls that function, in the latter case constructs
54 // GiNaC function with corresponding serial and arguments.
55 static ex dispatch_reader_fcn(const reader_func ptr, const exvector& args)
57 unsigned serial = 0; // dear gcc, could you please shut up?
58 bool is_ptr = decode_serial(serial, ptr);
62 return function(serial, args);
67 /// identifier_expr: identifier | identifier '(' expression* ')'
68 ex parser::parse_identifier_expr()
70 std::string name = scanner->str;
71 get_next_tok(); // eat identifier.
73 if (token != '(') // symbol
74 return find_or_insert_symbol(name, syms, strict);
76 // function/ctor call.
77 get_next_tok(); // eat (
81 ex e = parse_expression();
88 Parse_error("expected ')' or ',' in argument list");
95 prototype the_prototype = make_pair(name, args.size());
96 auto reader = funcs.find(the_prototype);
97 if (reader == funcs.end()) {
98 Parse_error_("no function \"" << name << "\" with " <<
99 args.size() << " arguments");
101 // reader->second might be a pointer to a C++ function or a specially
102 // crafted serial of a GiNaC::function.
103 ex ret = dispatch_reader_fcn(reader->second, args);
107 /// paren_expr: '(' expression ')'
108 ex parser::parse_paren_expr()
110 get_next_tok(); // eat (.
111 ex e = parse_expression();
114 Parse_error("expected ')'");
115 get_next_tok(); // eat ).
119 /// lst_expr: '{' expression { ',' expression } '}'
120 ex parser::parse_lst_expr()
122 get_next_tok(); // eat {.
127 ex e = parse_expression(); // expression();
135 Parse_error("expected '}'");
138 get_next_tok(); // eat ','.
147 extern const ex _ex0;
149 /// unary_expr: [+-] expression
150 ex parser::parse_unary_expr()
152 // Unlike most other parse_* method this one does NOT consume
153 // current token so parse_binop_rhs() knows what kind of operator
156 // There are different kinds of expressions which need to be handled:
161 // Delegate the work to parse_binop_rhs(), otherwise we end up
162 // duplicating it here.
163 ex lhs = _ex0; // silly trick
164 ex e = parse_binop_rhs(0, lhs);
168 /// primary: identifier_expr | number_expr | paren_expr | unary_expr
169 ex parser::parse_primary()
172 case lexer::token_type::identifier:
173 return parse_identifier_expr();
174 case lexer::token_type::number:
175 return parse_number_expr();
177 return parse_paren_expr();
179 return parse_lst_expr();
182 return parse_unary_expr();
183 case lexer::token_type::literal:
184 return parse_literal_expr();
185 case lexer::token_type::eof:
187 Parse_error("unexpected token");
191 /// expression ::= primary binoprhs
192 ex parser::parse_expression()
194 ex lhs = parse_primary();
195 ex res = parse_binop_rhs(0, lhs);
199 /// number_expr: number
200 ex parser::parse_number_expr()
202 ex n = numeric(scanner->str.c_str());
203 get_next_tok(); // consume the number
207 /// literal_expr: 'I' | 'Pi' | 'Euler' | 'Catalan'
208 ex parser::parse_literal_expr()
210 get_next_tok(); // consume the literal
211 if (scanner->str == "I")
213 else if (scanner->str == "Pi")
215 else if (scanner->str == "Euler")
217 else if (scanner->str == "Catalan")
219 bug("unknown literal: \"" << scanner->str << "\"");
222 ex parser::operator()(std::istream& input)
224 scanner->switch_input(&input);
226 ex ret = parse_expression();
227 // parse_expression() stops if it encounters an unknown token.
228 // This is not a bug: since the parser is recursive checking
229 // whether the next token is valid is responsibility of the caller.
230 // Hence make sure nothing is left in the stream:
231 if (token != lexer::token_type::eof)
232 Parse_error("expected EOF");
237 ex parser::operator()(const std::string& input)
239 std::istringstream is(input);
240 ex ret = operator()(is);
244 int parser::get_next_tok()
246 token = scanner->gettok();
250 parser::parser(const symtab& syms_, const bool strict_,
251 const prototype_table& funcs_) : strict(strict_),
252 funcs(funcs_), syms(syms_)
254 scanner = new lexer();