NAME

       Statistics::R::IO::REXPFactory - Functions for parsing R data files

VERSION

       version 1.0002

SYNOPSIS

           use Statistics::R::IO::REXPFactory qw( unserialize );

           # Assume $data was created by reading, say, an RDS file
           my ($rexp, $state) = @{unserialize($data)}
               or die "couldn't parse";

           # If we're reading an RDS file, there should be no data left
           # unparsed
           die 'Unread data remaining in the RDS file' unless $state->eof;

           # the result of the unserialization is a REXP
           say $rexp;

           # REXPs can be converted to the closest native Perl data type
           print $rexp->to_pl;

DESCRIPTION

       This module implements the actual reading of serialized R objects and their conversion to
       a Statistics::R::REXP. You are not expected to use it directly, as it's normally wrapped
       by "readRDS" in Statistics::R::IO and "readRData" in Statistics::R::IO.

SUBROUTINES

       unserialize $data
           Constructs a Statistics::R::REXP object from its serialization in $data. Returns a
           pair of the object and the Statistics::R::IO::ParserState at the end of serialization.

       intsxp, langsxp, lglsxp, listsxp, rawsxp, realsxp, refsxp, strsxp, symsxp, vecsxp, envsxp,
       charsxp, cplxsxp, closxp, expsxp, s4sxp
           Parsers for the corresponding R SEXP-types.

       object_content
           Parses object info and its data by sequencing "unpack_object_info" and "object_data".

       unpack_object_info
           Parser for serialized object info structure. Returns a hash with keys "is_object",
           "has_attributes", "has_tag", "object_type", and "levels", each corresponding to the
           field in R serialization described in
           <http://cran.r-project.org/doc/manuals/r-release/R-ints.html#Serialization-Formats>.
           An additional key "flags" contains the full 32-bit value as stored in the file.

       object_data $obj_info
           Parser for a serialized R object, using the object type stored in $obj_info hash's
           "object_type" key to use the correct parser for the particular type.

       vector_and_attributes $object_info, $element_parser, $rexp_class
           Convenience parser for vectors, which are serialized first with a SEXP for the vector
           elements, followed by attributes stored as a tagged pairlist. Attributes are stored
           only if $object_info indicates their presence, while vector elements are parsed using
           $element_parser. Finally, the parsed attributes and elements are used as arguments to
           the constructor of the $rexp_class, which should be a subclass of
           Statistics::R::REXP::Vector.

       header
           Parser for header of R serialization: the serialization format (XDR, binary, etc.),
           the version number of the serialization (currently 2), and two 32-bit integers
           indicating the version of R which wrote the file followed by the minimal version of R
           needed to read the format.

       xdr, bin
           Parsers for RDS header indicating files in XDR or native-binary format.

       maybe_long_length
           Parser for vector length, allowing for the encoding of 64-bit long vectors introduced
           in R 3.0.

       tagged_pairlist_to_rexp_hash
           Converts a pairlist to a REXP hash whose keys are the pairlist's element tags and
           values the pairlist elements themselves.

       tagged_pairlist_to_attribute_hash
           Converts object attributes, which are serialized as a pairlist with attribute name in
           the element's tag, to a hash that can be used as the "attributes" argument to
           Statistics::R::REXP constructors.

           Some attributes are serialized using a compact encoding (for instance, when a table's
           row names are just integers 1:nrows), and this function will decode them to a complete
           REXP.

BUGS AND LIMITATIONS

       There are no known bugs in this module. Please see Statistics::R::IO for bug reporting.

SUPPORT

       See Statistics::R::IO for support and contact information.

AUTHOR

       Davor Cubranic <cubranic@stat.ubc.ca>

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2017 by University of British Columbia.

       This is free software, licensed under:

         The GNU General Public License, Version 3, June 2007