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.IX Title "Module::CPANfile 3"
.TH Module::CPANfile 3 2026-10-26 "perl v5.44.0" "User Contributed Perl Documentation"
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.SH NAME
Module::CPANfile \- Parse cpanfile
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\&  use Module::CPANfile;
\&
\&  my $file = Module::CPANfile\->load("cpanfile");
\&  my $prereqs = $file\->prereqs; # CPAN::Meta::Prereqs object
\&
\&  my @features = $file\->features; # CPAN::Meta::Feature objects
\&  my $merged_prereqs = $file\->prereqs_with(@identifiers); # CPAN::Meta::Prereqs
\&
\&  $file\->merge_meta(\*(AqMYMETA.json\*(Aq);
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
Module::CPANfile is a tool to handle cpanfile format to load application
specific dependencies, not just for CPAN distributions.
.SH METHODS
.IX Header "METHODS"
.IP load 4
.IX Item "load"
.Vb 2
\&  $file = Module::CPANfile\->load;
\&  $file = Module::CPANfile\->load(\*(Aqcpanfile\*(Aq);
.Ve
.Sp
Load and parse a cpanfile. By default it tries to load \f(CW\*(C`cpanfile\*(C'\fR in
the current directory, unless you pass the path to its argument.
.IP from_prereqs 4
.IX Item "from_prereqs"
.Vb 3
\&  $file = Module::CPANfile\->from_prereqs({
\&    runtime => { requires => { DBI => \*(Aq1.000\*(Aq } },
\&  });
.Ve
.Sp
Creates a new Module::CPANfile object from prereqs hash you can get
via CPAN::Meta\*(Aqs \f(CW\*(C`prereqs\*(C'\fR, or CPAN::Meta::Prereqs\*(Aq
\&\f(CW\*(C`as_string_hash\*(C'\fR.
.Sp
.Vb 3
\&  # read MYMETA, then feed the prereqs to create Module::CPANfile
\&  my $meta = CPAN::Meta\->load_file(\*(AqMYMETA.json\*(Aq);
\&  my $file = Module::CPANfile\->from_prereqs($meta\->prereqs);
\&
\&  # load cpanfile, then recreate it with round\-trip
\&  my $file = Module::CPANfile\->load(\*(Aqcpanfile\*(Aq);
\&  $file = Module::CPANfile\->from_prereqs($file\->prereq_specs);
\&                                    # or $file\->prereqs\->as_string_hash
.Ve
.IP prereqs 4
.IX Item "prereqs"
Returns CPAN::Meta::Prereqs object out of the parsed cpanfile.
.IP prereq_specs 4
.IX Item "prereq_specs"
Returns a hash reference that should be passed to \f(CW\*(C`CPAN::Meta::Prereqs\->new\*(C'\fR.
.IP features 4
.IX Item "features"
Returns a list of features available in the cpanfile as CPAN::Meta::Feature.
.IP "prereqs_with(@identifiers), effective_prereqs(\e@identifiers)" 4
.IX Item "prereqs_with(@identifiers), effective_prereqs(@identifiers)"
Returns CPAN::Meta::Prereqs object, with merged prereqs for
features identified with the \f(CW@identifiers\fR.
.IP to_string($include_empty) 4
.IX Item "to_string($include_empty)"
.Vb 2
\&  $file\->to_string;
\&  $file\->to_string(1);
.Ve
.Sp
Returns a canonical string (code) representation for cpanfile. Useful
if you want to convert CPAN::Meta::Prereqs to a new cpanfile.
.Sp
.Vb 4
\&  # read MYMETA\*(Aqs prereqs and print cpanfile representation of it
\&  my $meta = CPAN::Meta\->load_file(\*(AqMYMETA.json\*(Aq);
\&  my $file = Module::CPANfile\->from_prereqs($meta\->prereqs);
\&  print $file\->to_string;
.Ve
.Sp
By default, it omits the phase where there\*(Aqre no modules
registered. If you pass the argument of a true value, it will print
them as well.
.IP save 4
.IX Item "save"
.Vb 1
\&  $file\->save(\*(Aqcpanfile\*(Aq);
.Ve
.Sp
Saves the currently loaded prereqs as a new \f(CW\*(C`cpanfile\*(C'\fR by calling
\&\f(CW\*(C`to_string\*(C'\fR. Beware \fBthis method will overwrite the existing
cpanfile without any warning or backup\fR. Taking a backup or giving
warnings to users is a caller\*(Aqs responsibility.
.Sp
.Vb 4
\&  # Read MYMETA.json and creates a new cpanfile
\&  my $meta = CPAN::Meta\->load_file(\*(AqMYMETA.json\*(Aq);
\&  my $file = Module::CPANfile\->from_prereqs($meta\->prereqs);
\&  $file\->save(\*(Aqcpanfile\*(Aq);
.Ve
.IP merge_meta 4
.IX Item "merge_meta"
.Vb 2
\&  $file\->merge_meta(\*(AqMETA.yml\*(Aq);
\&  $file\->merge_meta(\*(AqMYMETA.json\*(Aq, \*(Aq2.0\*(Aq);
.Ve
.Sp
Merge the effective prereqs with Meta specification loaded from the
given META file, using CPAN::Meta. You can specify the META spec
version in the second argument, which defaults to 1.4 in case the
given file is YAML, and 2 if it is JSON.
.IP options_for_module 4
.IX Item "options_for_module"
.Vb 1
\&  my $options = $file\->options_for_module($module);
.Ve
.Sp
Returns the extra options specified for a given module as a hash
reference. Returns \f(CW\*(C`undef\*(C'\fR when the given module is not specified in
the \f(CW\*(C`cpanfile\*(C'\fR.
.Sp
For example,
.Sp
.Vb 3
\&  # cpanfile
\&  requires \*(AqPlack\*(Aq, \*(Aq1.000\*(Aq,
\&    dist => "MIYAGAWA/Plack\-1.000.tar.gz";
\&
\&  # ...
\&  my $file = Module::CPANfile\->load;
\&  my $options = $file\->options_for_module(\*(AqPlack\*(Aq);
\&  # => { dist => "MIYAGAWA/Plack\-1.000.tar.gz" }
.Ve
.SH AUTHOR
.IX Header "AUTHOR"
Tatsuhiko Miyagawa
.SH "SEE ALSO"
.IX Header "SEE ALSO"
cpanfile, CPAN::Meta, CPAN::Meta::Spec