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 ?
hello, actually i want to generate rgram in yacc able to do do several operations separated by ';' and after show all the results separated by ';' again.
My code do just one operations and i couldn' t find solution to do several ones separated by ';'. I thought may be i can do a do... while but i... (0 Replies)
Hi guys,
I'm struggling with a simple but at the same time complicated problem related to yacc :wall: Maybe someone can help me with this :confused:
I'm working on a big project and it's hard for me to show the problem exactly on my code, but I will give a model of it.
Before I had this kind... (2 Replies)
How to specify the token length in a yacc file?
sample input format
<field1,data type ans,fixed length 6> followed by <field2,data type ans,fixed length 3>
Example i/p and o/p
Sample Input: "ab* d2 9o"
O/p : "Field1 Field2 "
yacc/bison grammar:
record :... (1 Reply)
Hi ,
I need to develop a parser which should match something like
1. text a=5 " a=20";
2. text a=..."
a=20";
3 text a=..."
a=20
b=34
c=12
";
I have used this regular expression in my Lex file to generate the tokens:
\".\s*.*\s.\" (8 Replies)
Hi all
I am using lex for my application scanning and I need to skip some lines for which I don't know the exact pattern.
So, could anybody tell me the regular expression to display lines NOT beginning with the specified pattern.
I know how to display lines beginning with the... (1 Reply)
Hi,
I need to read one chinese char using lex. I tried using "." ( period ) for pattern matching but in vain.
Could anyone suggest me how do i proceeed.
Sample pgm: to read a chinese char in single quotes.
%{
#include <locale.h>
%}
%%
\'.\' printf("SUCCESS\n");
. ... (0 Replies)
this is my lex file ------------ test.l
%%
printf("%c",yytext+'a'-'A');.ECHO;
how do i compile it
$ lex test.l cc lex.yy.c -o test -ll <------|
|
if this is correct do i add this line--------| @the command line or does it... (0 Replies)
YACC(1) General Commands Manual YACC(1)NAME
yacc - yet another compiler-compiler
SYNOPSIS
yacc [ -vd ] grammar
DESCRIPTION
Yacc converts a context-free grammar into a set of tables for a simple automaton which executes an LR(1) parsing algorithm. The grammar
may be ambiguous; specified precedence rules are used to break ambiguities.
The output file, y.tab.c, must be compiled by the C compiler to produce a program yyparse. This program must be loaded with the lexical
analyzer program, yylex, as well as main and yyerror, an error handling routine. These routines must be supplied by the user; Lex(1) is
useful for creating lexical analyzers usable by yacc.
If the -v flag is given, the file y.output is prepared, which contains a description of the parsing tables and a report on conflicts gener-
ated by ambiguities in the grammar.
If the -d flag is used, the file y.tab.h is generated with the define statements that associate the yacc-assigned `token codes' with the
user-declared `token names'. This allows source files other than y.tab.c to access the token codes.
FILES
y.output
y.tab.c
y.tab.h defines for token names
yacc.tmp, yacc.acts temporary files
/usr/share/misc/yaccparparser prototype for C programs
SEE ALSO lex(1)
LR Parsing by A. V. Aho and S. C. Johnson, Computing Surveys, June, 1974.
YACC - Yet Another Compiler Compiler by S. C. Johnson.
DIAGNOSTICS
The number of reduce-reduce and shift-reduce conflicts is reported on the standard output; a more detailed report is found in the y.output
file. Similarly, if some rules are not reachable from the start symbol, this is also reported.
BUGS
Because file names are fixed, at most one yacc process can be active in a given directory at a time.
7th Edition October 22, 1996 YACC(1)
