NAME

       ExtUtils::Typemaps - Read/Write/Modify Perl/XS typemap files

SYNOPSIS

         # read/create file
         my $typemap = ExtUtils::Typemaps->new(file => 'typemap');
         # alternatively create an in-memory typemap
         # $typemap = ExtUtils::Typemaps->new();
         # alternatively create an in-memory typemap by parsing a string
         # $typemap = ExtUtils::Typemaps->new(string => $sometypemap);

         # add a mapping
         $typemap->add_typemap(ctype => 'NV', xstype => 'T_NV');
         $typemap->add_inputmap(
            xstype => 'T_NV', code => '$var = ($type)SvNV($arg);'
         );
         $typemap->add_outputmap(
            xstype => 'T_NV', code => 'sv_setnv($arg, (NV)$var);'
         );
         $typemap->add_string(string => $typemapstring);
                                                  # will be parsed and merged

         # remove a mapping (same for remove_typemap and remove_outputmap...)
         $typemap->remove_inputmap(xstype => 'SomeType');

         # save a typemap to a file
         $typemap->write(file => 'anotherfile.map');

         # merge the other typemap into this one
         $typemap->merge(typemap => $another_typemap);

DESCRIPTION

       This module can read, modify, create and write Perl XS typemap files. If you don't know
       what a typemap is, please confer the perlxstut and perlxs manuals.

       The module is not entirely round-trip safe: For example it currently simply strips all
       comments.  The order of entries in the maps is, however, preserved.

       We check for duplicate entries in the typemap, but do not check for missing "TYPEMAP"
       entries for "INPUTMAP" or "OUTPUTMAP" entries since these might be hidden in a different
       typemap.

METHODS

   new
       Returns a new typemap object. Takes an optional "file" parameter.  If set, the given file
       will be read. If the file doesn't exist, an empty typemap is returned.

       Alternatively, if the "string" parameter is given, the supplied string will be parsed
       instead of a file.

   file
       Get/set the file that the typemap is written to when the "write" method is called.

   add_typemap
       Add a "TYPEMAP" entry to the typemap.

       Required named arguments: The "ctype" (e.g. "ctype => 'double'") and the "xstype" (e.g.
       "xstype => 'T_NV'").

       Optional named arguments: "replace => 1" forces removal/replacement of existing "TYPEMAP"
       entries of the same "ctype". "skip => 1" triggers a "first come first serve" logic by
       which new entries that conflict with existing entries are silently ignored.

       As an alternative to the named parameters usage, you may pass in an
       "ExtUtils::Typemaps::Type" object as first argument, a copy of which will be added to the
       typemap. In that case, only the "replace" or "skip" named parameters may be used after the
       object. Example:

         $map->add_typemap($type_obj, replace => 1);

   add_inputmap
       Add an "INPUT" entry to the typemap.

       Required named arguments: The "xstype" (e.g. "xstype => 'T_NV'") and the "code" to
       associate with it for input.

       Optional named arguments: "replace => 1" forces removal/replacement of existing "INPUT"
       entries of the same "xstype". "skip => 1" triggers a "first come first serve" logic by
       which new entries that conflict with existing entries are silently ignored.

       As an alternative to the named parameters usage, you may pass in an
       "ExtUtils::Typemaps::InputMap" object as first argument, a copy of which will be added to
       the typemap. In that case, only the "replace" or "skip" named parameters may be used after
       the object. Example:

         $map->add_inputmap($type_obj, replace => 1);

   add_outputmap
       Add an "OUTPUT" entry to the typemap.  Works exactly the same as "add_inputmap".

   add_string
       Parses a string as a typemap and merge it into the typemap object.

       Required named argument: "string" to specify the string to parse.

   remove_typemap
       Removes a "TYPEMAP" entry from the typemap.

       Required named argument: "ctype" to specify the entry to remove from the typemap.

       Alternatively, you may pass a single "ExtUtils::Typemaps::Type" object.

   remove_inputmap
       Removes an "INPUT" entry from the typemap.

       Required named argument: "xstype" to specify the entry to remove from the typemap.

       Alternatively, you may pass a single "ExtUtils::Typemaps::InputMap" object.

   remove_outputmap
       Removes an "OUTPUT" entry from the typemap.

       Required named argument: "xstype" to specify the entry to remove from the typemap.

       Alternatively, you may pass a single "ExtUtils::Typemaps::OutputMap" object.

   get_typemap
       Fetches an entry of the TYPEMAP section of the typemap.

       Mandatory named arguments: The "ctype" of the entry.

       Returns the "ExtUtils::Typemaps::Type" object for the entry if found.

   get_inputmap
       Fetches an entry of the INPUT section of the typemap.

       Mandatory named arguments: The "xstype" of the entry or the "ctype" of the typemap that
       can be used to find the "xstype". To wit, the following pieces of code are equivalent:

         my $type = $typemap->get_typemap(ctype => $ctype)
         my $input_map = $typemap->get_inputmap(xstype => $type->xstype);

         my $input_map = $typemap->get_inputmap(ctype => $ctype);

       Returns the "ExtUtils::Typemaps::InputMap" object for the entry if found.

   get_outputmap
       Fetches an entry of the OUTPUT section of the typemap.

       Mandatory named arguments: The "xstype" of the entry or the "ctype" of the typemap that
       can be used to resolve the "xstype". (See above for an example.)

       Returns the "ExtUtils::Typemaps::InputMap" object for the entry if found.

   write
       Write the typemap to a file. Optionally takes a "file" argument. If given, the typemap
       will be written to the specified file. If not, the typemap is written to the currently
       stored file name (see "file" above, this defaults to the file it was read from if any).

   as_string
       Generates and returns the string form of the typemap.

   as_embedded_typemap
       Generates and returns the string form of the typemap with the appropriate prefix around it
       for verbatim inclusion into an XS file as an embedded typemap. This will return a string
       like

         TYPEMAP: <<END_OF_TYPEMAP
         ... typemap here (see as_string) ...
         END_OF_TYPEMAP

       The method takes care not to use a HERE-doc end marker that appears in the typemap string
       itself.

   merge
       Merges a given typemap into the object. Note that a failed merge operation leaves the
       object in an inconsistent state so clone it if necessary.

       Mandatory named arguments: Either "typemap => $another_typemap_obj" or "file =>
       $path_to_typemap_file" but not both.

       Optional arguments: "replace => 1" to force replacement of existing typemap entries
       without warning or "skip => 1" to skip entries that exist already in the typemap.

   is_empty
       Returns a bool indicating whether this typemap is entirely empty.

   list_mapped_ctypes
       Returns a list of the C types that are mappable by this typemap object.

   _get_typemap_hash
       Returns a hash mapping the C types to the XS types:

         {
           'char **' => 'T_PACKEDARRAY',
           'bool_t' => 'T_IV',
           'AV *' => 'T_AVREF',
           'InputStream' => 'T_IN',
           'double' => 'T_DOUBLE',
           # ...
         }

       This is documented because it is used by "ExtUtils::ParseXS", but it's not intended for
       general consumption. May be removed at any time.

   _get_inputmap_hash
       Returns a hash mapping the XS types (identifiers) to the corresponding INPUT code:

         {
           'T_CALLBACK' => '   $var = make_perl_cb_$type($arg)
         ',
           'T_OUT' => '    $var = IoOFP(sv_2io($arg))
         ',
           'T_REF_IV_PTR' => '   if (sv_isa($arg, \\"${ntype}\\")) {
           # ...
         }

       This is documented because it is used by "ExtUtils::ParseXS", but it's not intended for
       general consumption. May be removed at any time.

   _get_outputmap_hash
       Returns a hash mapping the XS types (identifiers) to the corresponding OUTPUT code:

         {
           'T_CALLBACK' => '   sv_setpvn($arg, $var.context.value().chp(),
                       $var.context.value().size());
         ',
           'T_OUT' => '    {
                   GV *gv = (GV *)sv_newmortal();
                   gv_init_pvn(gv, gv_stashpvs("$Package",1),
                              "__ANONIO__",10,0);
                   if ( do_open(gv, "+>&", 3, FALSE, 0, 0, $var) )
                       sv_setsv(
                         $arg,
                         sv_bless(newRV((SV*)gv), gv_stashpv("$Package",1))
                       );
                   else
                       $arg = &PL_sv_undef;
                }
         ',
           # ...
         }

       This is documented because it is used by "ExtUtils::ParseXS", but it's not intended for
       general consumption. May be removed at any time.

   _get_prototype_hash
       Returns a hash mapping the C types of the typemap to their corresponding prototypes.

         {
           'char **' => '$',
           'bool_t' => '$',
           'AV *' => '$',
           'InputStream' => '$',
           'double' => '$',
           # ...
         }

       This is documented because it is used by "ExtUtils::ParseXS", but it's not intended for
       general consumption. May be removed at any time.

   clone
       Creates and returns a clone of a full typemaps object.

       Takes named parameters: If "shallow" is true, the clone will share the actual individual
       type/input/outputmap objects, but not share their storage. Use with caution. Without
       "shallow", the clone will be fully independent.

   tidy_type
       Function to (heuristically) canonicalize a C type. Works to some degree with C++ types.

           $halfway_canonical_type = tidy_type($ctype);

       Moved from "ExtUtils::ParseXS".

CAVEATS

       Inherits some evil code from "ExtUtils::ParseXS".

SEE ALSO

       The parser is heavily inspired from the one in ExtUtils::ParseXS.

       For details on typemaps: perlxstut, perlxs.

AUTHOR

       Steffen Mueller "<smueller@cpan.org">

COPYRIGHT & LICENSE

       Copyright 2009, 2010, 2011, 2012, 2013 Steffen Mueller

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