B::Xref(3) Perl Programmers Reference Guide B::Xref(3)NAMEB::Xref - Generates cross reference reports for Perl pro
grams
SYNOPSIS
perl -MO=Xref[,OPTIONS] foo.pl
DESCRIPTION
The B::Xref module is used to generate a cross reference
listing of all definitions and uses of variables, subrou
tines and formats in a Perl program. It is implemented as
a backend for the Perl compiler.
The report generated is in the following format:
File filename1
Subroutine subname1
Package package1
object1 C<line numbers>
object2 C<line numbers>
...
Package package2
...
Each File section reports on a single file. Each Subrou
tine section reports on a single subroutine apart from the
special cases "(definitions)" and "(main)". These report,
respectively, on subroutine definitions found by the ini
tial symbol table walk and on the main part of the program
or module external to all subroutines.
The report is then grouped by the Package of each vari
able, subroutine or format with the special case "(lexi
cals)" meaning lexical variables. Each object name
(implicitly qualified by its containing Package) includes
its type character(s) at the beginning where possible.
Lexical variables are easier to track and even included
dereferencing information where possible.
The "line numbers" are a comma separated list of line num
bers (some preceded by code letters) where that object is
used in some way. Simple uses aren't preceded by a code
letter. Introductions (such as where a lexical is first
defined with "my") are indicated with the letter "i". Sub
routine and method calls are indicated by the character
"&". Subroutine definitions are indicated by "s" and for
mat definitions by "f".
OPTIONS
Option words are separated by commas (not whitespace) and
follow the usual conventions of compiler backend options.
""-oFILENAME""
Directs output to "FILENAME" instead of standard
output.
""-r"" Raw output. Instead of producing a human-readable
report, outputs a line in machine-readable form
for each definition/use of a variable/sub/format.
""-D[tO]""
(Internal) debug options, probably only useful if
"-r" included. The "t" option prints the object
on the top of the stack as it's being tracked. The
"O" option prints each operator as it's being pro
cessed in the execution order of the program.
BUGS
Non-lexical variables are quite difficult to track through
a program. Sometimes the type of a non-lexical variable's
use is impossible to determine. Introductions of non-lexi
cal non-scalars don't seem to be reported properly.
AUTHOR
Malcolm Beattie, mbeattie@sable.ox.ac.uk.
2001-02-22 perl v5.6.1 B::Xref(3)
