


ext::B::B::Xref(3Perl Programmers Reference Guext::B::B::Xref(3p)


NAME
       B::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



2000-04-06                 perl v5.6.1                          1





ext::B::B::Xref(3Perl Programmers Reference Guext::B::B::Xref(3p)


               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.




































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