Rserve::QapEncoding - Functions for parsing Rserve packets
use Rserve::QapEncoding qw(decode);
# Assume $data comes from an Rserve response body.
my ($rexp, $state) = @{ decode($data) } or die "couldn't parse";
# If reading a QAP response, there should be no data left unparsed.
die 'Unread data remaining' 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 $rexp->to_perl;This module implements the actual reading of serialized R objects encoded with Rserve's QAP protocol and their conversion to a Rserve::REXP. You are not expected to use it directly, as it's normally wrapped by "eval" in Rserve.
decode($data)Constructs a Rserve::REXP object from its serialization in $data. Returns a pair of the object and the Rserve::ParserState at the end of serialization.
Parsers for Rserve's DT_SEXP and DT_INT data types, respectively.
Parses the body of an RServe DT_SEXP object by parsing its header (XT_ type and length) and content (done by sequencing "unpack_sexp_info" and "sexp_data".
Parser for the header (consisting of the XT_* type, flags, and object length) of a serialized SEXP. Returns a hash with keys "object_type", "has_attributes", and "length", each corresponding to the field in R serialization described in QAP1 protocol description.
sexp_data($obj_info)Parser for a QAP-serialized R object, using the object type stored in $obj_info hash's "object_type" key to use the correct parser for the particular type.
Parsers for the corresponding R SEXP-types.
Parser for the Rserve's XT_UNKNOWN type, encoding an R SEXP-type that does not have a corresponding representation in QAP.
maybe_attributes($object_info)Convenience parser for SEXP attributes, which are serialized as a tagged pairlist XT_LIST_TAG followed by a SEXP for the object value. Attributes are stored only if $object_info indicates their presence. Returns a pair of $object_info and a hash reference to the attributes, as returned by "tagged_pairlist_to_attribute_hash".
Parses a pairlist (optionally tagged) and returns an array where each element is a hash containing keys value (the REXP of the pairlist element) and, optionally, tag.
Converts a pairlist to a REXP hash whose keys are the pairlist's element tags and values the pairlist elements themselves.
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 Rserve::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.