```{index} single: B::Showlex ``` # B::Showlex Show lexical variables used in functions or files ## SYNOPSIS ```text 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 $ 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 $ 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 $ 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. ## SEE ALSO [B::Showlex](Showlex.md) can also be used outside of the O framework, as in the third example. See [B::Concise](Concise.md) 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`