annotate planemo/lib/python3.7/site-packages/rdflib/plugins/sparql/results/tsvresults.py @ 1:56ad4e20f292 draft

"planemo upload commit 6eee67778febed82ddd413c3ca40b3183a3898f1"

"""
This implements the Tab Separated SPARQL Result Format

It is implemented with pyparsing, reusing the elements from the SPARQL Parser
"""

import codecs

from pyparsing import (
    Optional, ZeroOrMore, Literal, ParserElement, ParseException, Suppress,
    FollowedBy, LineEnd)

from rdflib.query import Result, ResultParser

from rdflib.plugins.sparql.parser import (
    Var, STRING_LITERAL1, STRING_LITERAL2, IRIREF, BLANK_NODE_LABEL,
    NumericLiteral, BooleanLiteral, LANGTAG)
from rdflib.plugins.sparql.parserutils import Comp, Param, CompValue

from rdflib import Literal as RDFLiteral

from rdflib.py3compat import bytestype

ParserElement.setDefaultWhitespaceChars(" \n")


String = STRING_LITERAL1 | STRING_LITERAL2

RDFLITERAL = Comp('literal', Param('string', String) + Optional(
    Param('lang', LANGTAG.leaveWhitespace()
          ) | Literal('^^').leaveWhitespace(
    ) + Param('datatype', IRIREF).leaveWhitespace()))

NONE_VALUE = object()

EMPTY = FollowedBy(LineEnd()) | FollowedBy("\t")
EMPTY.setParseAction(lambda x: NONE_VALUE)

TERM = RDFLITERAL | IRIREF | BLANK_NODE_LABEL | NumericLiteral | BooleanLiteral

ROW = (EMPTY | TERM) + ZeroOrMore(Suppress("\t") + (EMPTY | TERM))
ROW.parseWithTabs()

HEADER = Var + ZeroOrMore(Suppress("\t") + Var)
HEADER.parseWithTabs()


class TSVResultParser(ResultParser):
    def parse(self, source):

        if isinstance(source.read(0), bytestype):
            # if reading from source returns bytes do utf-8 decoding
            source = codecs.getreader('utf-8')(source)

        try:
            r = Result('SELECT')

            header = source.readline()

            r.vars = list(HEADER.parseString(header.strip(), parseAll=True))
            r.bindings = []
            while True:
                line = source.readline()
                if not line:
                    break
                line = line.strip('\n')
                if line == "":
                    continue

                row = ROW.parseString(line, parseAll=True)
                r.bindings.append(
                    dict(list(zip(r.vars, (self.convertTerm(x) for x in row)))))

            return r

        except ParseException as err:
            print(err.line)
            print(" " * (err.column - 1) + "^")
            print(err)

    def convertTerm(self, t):
        if t is NONE_VALUE:
            return None
        if isinstance(t, CompValue):
            if t.name == 'literal':
                return RDFLiteral(t.string, lang=t.lang, datatype=t.datatype)
            else:
                raise Exception("I dont know how to handle this: %s" % (t,))
        else:
            return t

if __name__ == '__main__':
    import sys
    r = Result.parse(file(sys.argv[1]), format='tsv')
    print(r.vars)
    print(r.bindings)
    # print r.serialize(format='json')