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| author | Gerard Beekmans <gerard@linuxfromscratch.org> | 2001-02-15 15:26:52 +0000 |
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| committer | Gerard Beekmans <gerard@linuxfromscratch.org> | 2001-02-15 15:26:52 +0000 |
| commit | b08f4096533577934b885fa9df41d3881d141612 (patch) | |
| tree | 8e5ffc0ba65ac34d97cd6a896d33b85a897a6da8 /appendixa/bison-desc.sgml | |
| parent | ad08014624938a3a3bfd1b44e8b27d02c7b06dd8 (diff) | |
Initial XML commit
git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@174 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
Diffstat (limited to 'appendixa/bison-desc.sgml')
| -rw-r--r-- | appendixa/bison-desc.sgml | 67 |
1 files changed, 0 insertions, 67 deletions
diff --git a/appendixa/bison-desc.sgml b/appendixa/bison-desc.sgml deleted file mode 100644 index 7e3fff7e9..000000000 --- a/appendixa/bison-desc.sgml +++ /dev/null @@ -1,67 +0,0 @@ -<sect2> -<title>Contents</title> - -<para> -The Bison package contains the bison program. -</para> - -</sect2> - -<sect2><title>Description</title> - -<para> -Bison is a parser generator, a replacement for YACC. YACC stands for Yet -Another Compiler Compiler. What is Bison then? It is a program that -generates a program that analyses the structure of a textfile. Instead -of -writing the actual program you specify how things should be connected -and with -those rules a program is constructed that analyses the textfile. -</para> - -<para> -There are alot of examples where structure is needed and one of them is -the -calculator. -</para> - -<para> -Given the string : -</para> - -<blockquote><literallayout> - 1 + 2 * 3 -</literallayout></blockquote> - -<para> -You can easily come to the result 7. Why ? Because of the structure. You -know -how to interpretet the string. The computer doesn't know that and Bison -is a -tool to help it understand by presenting the string in the following way -to the compiler: -</para> - -<blockquote><literallayout> - - + - / \ - * 1 - / \ - 2 3 -</literallayout></blockquote> - -<para> -You start at the bottom of a tree and you come across the numbers 2 and -3 which are joined by the multiplication symbol, so the computers -multiplies 2 and 3. The result of that multiplication is remembered and -the next thing that the computer sees is the result of 2*3 and the -number 1 which are joined by the add symbol. Adding 1 to the previous -result makes 7. In calculating the most complex calculations can be -broken down in this tree format and the computer just starts at the -bottom and works it's way up to the top and comes with the correct -answer. Of course, Bison isn't only used for calculators alone. -</para> - -</sect2> - |