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: SPECIAL #1 &PL_sv_undef 1: PVNV (0x9db0fb0) $i 2: PVNV (0x9db0f38) $j 3: PVNV (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,$k)=(1,"foo")' main Pad has 4 entries 0: SPECIAL #1 &PL_sv_undef 1: PVNV (0xa0c4fb8) "$i" = NULL (0xa0b8234) 2: PVNV (0xa0c4f40) "$j" = NULL (0xa0c4f34) 3: PVNV (0xa0c4f58) "$k" = NULL (0xa0c4f4c) -e syntax OK
New form, no specials, outside O framework:
$ perl -MB::Showlex -e \
'my ($i,$j,$k)=(1,"foo"); B::Showlex::compile(-newlex,-nosp)->()'
main Pad has 4 entries
1: PVNV (0x998ffb0) "$i" = IV (0x9983234) 1
2: PVNV (0x998ff68) "$j" = PV (0x998ff5c) "foo"
3: PVNV (0x998ff80) "$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.
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 isnt a particularly good flag-name.
AUTHOR
Malcolm Beattie, mbeattie@sable.ox.ac.uk
