ext::B::B::ShowlePerl)Programmers Referenceext::B::B::Showlex(3p)NAMEB::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).
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ext::B::B::ShowlePerl)Programmers Referenceext::B::B::Showlex(3p)
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 expla-
nation of reasons.
TODO
Some of the reported info, such as hex addresses, is not
particularly valuable. Other information would be more use-
ful 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"
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