On 3/8/07, Dharshana Eswaran <[EMAIL PROTECTED]> wrote:
Hi all,
I need to extract few strings from one file and paste it to another file.
snip
This doesn't seem like a good job for split. The split function is
good for parsing X separated records where X is either constant or
simple. What you have there a grammar. Specifically a subset of the
C grammar for #define. With grammars you want to use either a regex
or Parse::RecDescent depending on the complexity of the grammar. In
this case the grammar is simple enough that a regex does fine. I have
created a regex that parses your record into a name, base number,
operator, and modifying number. The last two values are optional. I
have used the x option on the regex to make it readable since it is so
large (anything bigger than 80 characters should probably use the x
option). You can learn more about regexes in perldoc perlre and
perldoc perlretut.
#!/usr/bin/perl
use strict;
use warnings;
while (<DATA>) {
my ($name, $base, $op, $mod) = m{
^ # start of string
\s* # optional spaces
\#define # the start of the macro
\s+ # mandatory spaces
(\w+) # capture the name of the macro
\s* # optional spaces
\( # the open paren
\s* # optional spaces
(
\w+ |
\d+ |
0x[a-fA-F0-9]
) # capture a word, int, or hex
\s* # optional spaces
(?:
( # capture the various int operators
[+-|^*/%] |
<< |
>>
)
\s* # optional spaces
( # capture a word, int, or hex
\w+ |
\d+ |
0x[a-fA-F0-9])
)? # but make the last two captures optional
\) # the close paren
}x;
$op = $mod = '' unless defined $op;
print;
print "\tname is $name, base is $base, modified by $mod using $op\n"
if $name;
}
__DATA__
#define GMMREG_ATTACH_REQ_ID (GMMREG_PRIM_ID_BASE)
/* @LOG GMMREG_ATTACH_REQ */
#define GMMREG_DETACH_REQ_ID (GMMREG_PRIM_ID_BASE | 0x0001)
/* @LOG GMMREG_DETACH_REQ */
/* GMMREG primitives sent by the MM sub-layer to the MMI */
#define GMMREG_ATTACH_CNF_ID (GMMREG_PRIM_ID_BASE | 0x0010)
/* @LOG GMMREG_ATTACH_CNF */
#define GMMREG_DETACH_CNF_ID (GMMREG_PRIM_ID_BASE | 0x0011)
/* @LOG GMMREG_DETACH_CNF */
#define CCL2D_INIT_NCNF_ID (L2D_PRIM_ID_BASE+5) /* @LOG
CCL2D_INIT_NCNF */
#define CCL2D_INIT_RESP_ID (L2D_PRIM_ID_BASE+6) /* @LOG
CCL2D_INIT_RESP */
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