B::Showlex - Show lexical variables used in functions or files
perl -MO=Showlex[,-OPTIONS][,SUBROUTINE] foo.pl
Perl Programmers Reference Guide B::Showlex(3)
NAME
B::Showlex - Show lexical variables used in functions or files
SYNOPSIS
perl -MO=Showlex[,-OPTIONS][,SUBROUTINE] foo.pl
DESCRIPTION
When a comma-separated list of subroutine names is given as options,
Showlex prints the lexical variables used in those subroutines.
Otherwise, it prints the file-scope lexicals in the file.
EXAMPLES
Traditional form:
$ perl -MO=Showlex -e 'my ($i,$j,$k)=(1,"foo")'
Pad of lexical names for comppadlist has 4 entries
0: (0x8caea4) undef
1: (0x9db0fb0) $i
2: (0x9db0f38) $j
3: (0x9db0f50) $k
Pad of lexical values for comppadlist has 5 entries
0: SPECIAL #1 &PL_sv_undef
1: NULL (0x9da4234)
2: NULL (0x9db0f2c)
3: NULL (0x9db0f44)
4: NULL (0x9da4264)
-e syntax OK
New-style form:
$ perl -MO=Showlex,-newlex -e 'my ($i,$j,$k)=(1,"foo")'
main Pad has 4 entries
0: (0x8caea4) undef
1: (0xa0c4fb8) "$i" = NULL (0xa0b8234)
2: (0xa0c4f40) "$j" = NULL (0xa0c4f34)
3: (0xa0c4f58) "$k" = NULL (0xa0c4f4c)
-e syntax OK
New form, no specials, outside O framework:
$ perl -MB::Showlex -e \
'my ($i,$j,$k)=(1,"foo"); B::Showlex::compile(-newlex,-nosp)->()'
main Pad has 4 entries
1: (0x998ffb0) "$i" = IV (0x9983234) 1
2: (0x998ff68) "$j" = PV (0x998ff5c) "foo"
3: (0x998ff80) "$k" = NULL (0x998ff74)
Note that this example shows the values of the lexicals, whereas the
other examples did not (as they're compile-time only).
OPTIONS
The "-newlex" option produces a more readable "name => value" format,
and is shown in the second example above.
The "-nosp" option eliminates reporting of SPECIALs, such as "0:
SPECIAL #1 &PL_sv_undef" above. Reporting of SPECIALs can sometimes
overwhelm your declared lexicals.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+-----------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------------+
|Availability | runtime/perl-532 |
+---------------+-----------------------+
|Stability | Pass-through volatile |
+---------------+-----------------------+
SEE ALSO
B::Showlex can also be used outside of the O framework, as in the third
example. See B::Concise for a fuller explanation of reasons.
TODO
Some of the reported info, such as hex addresses, is not particularly
valuable. Other information would be more useful for the typical
programmer, such as line-numbers, pad-slot reuses, etc.. Given this,
-newlex is not a particularly good flag-name.
AUTHOR
Malcolm Beattie, "mbeattie@sable.ox.ac.uk"
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
http://www.cpan.org/src/5.0/perl-5.32.0.tar.gz.
Further information about this software can be found on the open source
community website at https://www.perl.org/.
perl v5.32.0 2020-06-14 B::Showlex(3)