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https://github.com/jimmahoney/bison_calculator
A sample bison compiler
https://github.com/jimmahoney/bison_calculator
Last synced: 2 months ago
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A sample bison compiler
- Host: GitHub
- URL: https://github.com/jimmahoney/bison_calculator
- Owner: jimmahoney
- License: gpl-2.0
- Created: 2015-10-22T01:18:10.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2015-10-22T05:18:03.000Z (about 9 years ago)
- Last Synced: 2024-08-02T01:22:26.403Z (6 months ago)
- Language: C
- Size: 195 KB
- Stars: 9
- Watchers: 2
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# bison_calculator
A sample bison compiler based on https://en.wikipedia.org/wiki/GNU_bison -
an algebraic calculator definition and compilation example
including the creation and evaluation of a syntax tree.
## files
```
expression.h header file for syntax tree data structure
expression.c implementation of syntax tree
lexer.l Flex token specs
parser.y Bison language syntax specs
main.c call the Flex scanner and Bison parser
to make a syntax tree, then evaluate the tree
makefile compile everything
README.md you're looking at it
LICENSE
```
## software requirements
This works with the versions of flex and g++ which
are part of Mac OS 10.10.5. However, the default bison 2.3
doesn't understand the directives (i.e. "%code") from
the wikipedia example, so I manually installed 3.0.5
(wget .../bison-3.0.4.tar.gz; tar zxf ...; ./configure; make; make install)
to /usr/local/bin .
```
$ /usr/local/bin/bison --version
bison (GNU Bison) 3.0.4
$ flex --version
flex 2.5.35 Apple(flex-31)
$ g++ --version
Apple LLVM version 7.0.0 (clang-700.1.76)
Target: x86_64-apple-darwin14.5.0
```
## change history
* modified makefile to use bison in /usr/local/bin/bison
* adjusted C styling to suit my preferences
* removed yyerror() declration to avoid a compiler "duplicate symbol" error (apparently bison generates one of these too, and I didn't track down how to keep the new one instead)
* added "-x c " compiler flag to avoid compiler C++ warnings
# graphviz representation of the parse tree is now output to tree.dot in main.c
## running it
```
$ make
flex lexer.l
/usr/local/bin/bison parser.y
g++ -g -x c -ansi lexer.c parser.c expression.c main.c -o test
$ ./test # also creates tree.dot
Result of ' 4 + 2*10 + 3*( 5 + 1 ) ' is 42
# generate parse tree image from tree.dot
$ dot -Tpng < tree.dot > tree.png
```