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Data::Dump::Trace(3) User Contributed Perl Documentation Data::Dump::Trace(3)

NAME

Data::Dump::Trace - Helpers to trace function and method calls

SYNOPSIS

  use Data::Dump::Trace qw(autowrap mcall);
  autowrap("LWP::UserAgent" => "ua", "HTTP::Response" => "res");
  use LWP::UserAgent;
  $ua = mcall(LWP::UserAgent => "new");      # instead of LWP::UserAgent->new;
  $ua->get("http://www.example.com")->dump;

DESCRIPTION

The following functions are provided:

Register classes whose objects are automatically wrapped when returned by one of the call functions below. If $prefix is provided it will be used as to name the objects.

Alternative is to pass an %info hash for each class. The recognized keys are:

The prefix string used to name objects of this type.
A hash of prototypes to use for the methods when an object is wrapped.
Returns a wrapped function or object. When a wrapped function is invoked then a trace is printed after the underlying function has returned. When a method on a wrapped object is invoked then a trace is printed after the methods on the underlying objects has returned.

See "Prototypes" for description of the "proto" argument.

Calls the given function with the given arguments. The trace will use $name as the name of the function.

See "Prototypes" for description of the $proto argument.

Calls the given method with the given arguments.

See "Prototypes" for description of the $proto argument.

Replaces the function given by $symbol with a wrapped function.

Prototypes

Note: The prototype string syntax described here is experimental and likely to change in revisions of this interface.

The $proto argument to call() and mcall() can optionally provide a prototype for the function call. This give the tracer hints about how to best format the argument lists and if there are in/out or out arguments. The general form for the prototype string is:

   <arguments> = <return_value>

The default prototype is "@ = @"; list of values as input and list of values as output.

The value '%' can be used for both arguments and return value to say that key/value pair style lists are used.

Alternatively, individual positional arguments can be listed each represented by a letter:

"i"
input argument
"o"
output argument
"O"
both input and output argument

If the return value prototype has "!" appended, then it signals that this function sets errno ($!) when it returns a false value. The trace will display the current value of errno in that case.

If the return value prototype looks like a variable name (with "$" prefix), and the function returns a blessed object, then the variable name will be used as prefix and the returned object automatically traced.

SEE ALSO

Data::Dump

AUTHOR

Copyright 2009 Gisle Aas.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

2021-08-09 perl v5.32.1