NAME¶
B::Xref - Generates cross reference reports for Perl programs
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, subroutines 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 line numbers
object2 line numbers
...
Package package2
...
Each
File section reports on a single file. Each
Subroutine
section reports on a single subroutine apart from the special cases
"(definitions)" and "(main)". These report, respectively,
on subroutine definitions found by the initial 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 variable, subroutine or
format with the special case "(lexicals)" 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 numbers (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". Subroutine and method calls are indicated by the character
"&". Subroutine definitions are indicated by "s" and
format 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"
- Don't output the "(definitions)" sections.
- "-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 processed 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-lexical non-scalars don't seem to be reported properly.
AUTHOR¶
Malcolm Beattie, mbeattie@sable.ox.ac.uk.