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Suggested by Eric S. Raymond. https://lists.gnu.org/archive/html/bison-patches/2019-02/msg00066.html * examples/c/reentrant-calc/Makefile, examples/c/reentrant-calc/README.md, * examples/c/reentrant-calc/parse.y, examples/c/reentrant-calc/scan.l * examples/c/reentrant-calc/lexcalc.test, * examples/c/reentrant-calc/local.mk: New.
46 lines
1.3 KiB
Markdown
46 lines
1.3 KiB
Markdown
# reccalc - recursive calculator with Flex and Bison
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In this example the generated parser is pure and reentrant: it can be used
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concurrently in different threads, or recursively. As a proof of this
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reentrancy, expressions in parenthesis are tokenized as strings, and then
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recursively parsed from the parser:
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```
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exp: STR
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{
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result r = parse_string ($1);
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free ($1);
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if (r.nerrs)
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{
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res->nerrs += r.nerrs;
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YYERROR;
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}
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else
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$$ = r.value;
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}
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```
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<!---
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Local Variables:
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fill-column: 76
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ispell-dictionary: "american"
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End:
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Copyright (C) 2018-2019 Free Software Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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--->
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