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actions before parsing rules in lex n yacc


 
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Old 11-26-2008
actions before parsing rules in lex n yacc

Hi ,

We have developed a grammer for our domain language using lex n yacc.
I want to know is there any pre defined lex-yacc function which gets call before executing any rule (or rules).
Oue requirement is, before processing any rule ,we want to perform some specific actions ?
is there any pre defined lex-yacc function which get call before processing rules?

In case of ANTLR (Another Tool for Language Recognition), we can specify actions before processing rule using a block "@init" . Is there anything like "@init" in lex n yacc ?

Regards,
Suprit

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YACC(1) 						    BSD General Commands Manual 						   YACC(1)

NAME
yacc -- an LALR(1) parser generator SYNOPSIS
yacc [-dlrtv] [-b file_prefix] [-o output_filename] [-p symbol_prefix] filename DESCRIPTION
Yacc reads the grammar specification in the file filename and generates an LR(1) parser for it. The parsers consist of a set of LALR(1) parsing tables and a driver routine written in the C programming language. Yacc normally writes the parse tables and the driver routine to the file y.tab.c. The following options are available: -b file_prefix Change the prefix prepended to the output file names to the string denoted by file_prefix. The default prefix is the character y. -d Cause the header file y.tab.h to be written. -l If the -l option is not specified, yacc will insert #line directives in the generated code. The #line directives let the C compiler relate errors in the generated code to the user's original code. If the -l option is specified, yacc will not insert the #line directives. Any #line directives specified by the user will be retained. -o output_filename Cause yacc to write the generated code to output_filename instead of the default file, y.tab.c. -p symbol_prefix Change the prefix prepended to yacc-generated symbols to the string denoted by symbol_prefix. The default prefix is the string yy. -r Cause yacc to produce separate files for code and tables. The code file is named y.code.c, and the tables file is named y.tab.c. -t Change the preprocessor directives generated by yacc so that debugging statements will be incorporated in the compiled code. -v Cause a human-readable description of the generated parser to be written to the file y.output. If the environment variable TMPDIR is set, the string denoted by TMPDIR will be used as the name of the directory where the temporary files are created. FILES
y.code.c y.tab.c y.tab.h y.output /tmp/yacc.aXXXXXXXXXX /tmp/yacc.tXXXXXXXXXX /tmp/yacc.uXXXXXXXXXX DIAGNOSTICS
If there are rules that are never reduced, the number of such rules is reported on standard error. If there are any LALR(1) conflicts, the number of conflicts is reported on standard error. BSD
May 24, 1993 BSD

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