Provided by: perl-doc_5.26.1-6_all bug


       B::Showlex - Show lexical variables used in functions or files


               perl -MO=Showlex[,-OPTIONS][,SUBROUTINE]


       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.


       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).

       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.


       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.


       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.


       Malcolm Beattie, ""