B/Utils version 0.02
====================
NAME
B::Utils - Helper functions for op tree manipulation
What's new in this version:
* Fixed some brown-bag bugs
* Added the following Fun Things:
walkoptree_simple($op, \&callback, [$data])
The "B" module provides various functions to walk the op tree, but
they're all rather difficult to use, requiring you to inject methods
into the "B::OP" class. This is a very simple op tree walker with
more expected semantics.
All the "walk" functions set "B::Utils::file" and "B::Utils::line" to
the appropriate values of file and line number in the program being
examined.
walkoptree_filtered($op, \&filter, \&callback, [$data])
This is much the same as "walkoptree_simple", but will only call the
callback if the "filter" returns true. The "filter" is passed the op
in question as a parameter; the "opgrep" function is fantastic for
building your own filters.
walkallops_simple(\&callback, [$data])
This combines "walkoptree_simple" with "all_roots" and "anon_subs" to
examine every op in the program. "$B::Utils::sub" is set to the
subroutine name if you're in a subroutine, "__MAIN__" if you're in
the main program and "__ANON__" if you're in an anonymous subroutine.
walkallops_filtered(\&filter, \&callback, [$data])
Same as above, but filtered.
carp(@args)
croak(@args)
Warn and die, respectively, from the perspective of the position of
the op in the program. Sounds complicated, but it's exactly the kind
of error reporting you expect when you're grovelling through an op
tree.
opgrep(\%conditions, @ops)
Returns the ops which meet the given conditions. The conditions
should be specified like this:
@barewords = opgrep(
{ name => "const", private => OPpCONST_BARE },
@ops
);
You can specify alternation by giving an arrayref of values:
@svs = opgrep ( { name => ["padsv", "gvsv"] }, @ops)
And you can specify inversion by making the first element of the
arrayref a "!". (Hint: if you want to say "anything", say "not
nothing": "["!"]")
You may also specify the conditions to be matched in nearby ops.
walkallops_filtered(
sub { opgrep( {name => "exec",
next => {
name => "nextstate",
sibling => { name => [qw(! exit warn die)] }
}
}, @_)},
sub {
carp("Statement unlikely to be reached");
carp("\t(Maybe you meant system() when you said exec()?)\n");
}
)
Get that?
Here are the things that can be tested:
name targ type seq flags private pmflags pmpermflags
first other last sibling next pmreplroot pmreplstart pmnext
INSTALLATION
To install this module type the following:
perl Makefile.PL
make
make test
make install
DEPENDENCIES
This module does *not* require anything that's not in core.
COPYRIGHT AND LICENCE
AL & GPL. You know the score.
Copyright (C) 2001 Simon Cozens