test_parsers.py

#!/usr/bin/python3

"""test_parsers.py - tests of the parsers-module of DHParser 

Author: Eckhart Arnold <arnold@badw.de>

Copyright 2017 Bavarian Academy of Sciences and Humanities

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

from functools import partial
import sys
sys.path.extend(['../', './'])

from DHParser import parsers
from DHParser.toolkit import is_logging, compile_python_object
from DHParser.syntaxtree import no_operation, traverse, remove_expendables, \
    replace_by_single_child, reduce_single_child, flatten, TOKEN_PTYPE
from DHParser.parsers import compile_source
from DHParser.ebnf import get_ebnf_grammar, get_ebnf_transformer, get_ebnf_compiler
from DHParser.dsl import parser_factory, DHPARSER_IMPORTS


ARITHMETIC_EBNF = """
    @ whitespace = linefeed
    formula = [ //~ ] expr
    expr = expr ("+"|"-") term | term
    term = term ("*"|"/") factor | factor
    factor = /[0-9]+/~
    # example:  "5 + 3 * 4"
    """


ARITHMETIC_EBNF_transformation_table = {
    # AST Transformations for the DSL-grammar
    "formula": [remove_expendables],
    "term, expr": [replace_by_single_child, flatten],
    "factor": [remove_expendables, reduce_single_child],
    (TOKEN_PTYPE): [remove_expendables, reduce_single_child],
    "*": [remove_expendables, replace_by_single_child]
}


ARITHMETIC_EBNFTransform = partial(traverse, processing_table=ARITHMETIC_EBNF_transformation_table)


class TestGrammarTest:
    cases = {
        "factor": {
            "match": {
                1: "0",
                2: "314",
            },
            "fail": {
                3: "21F",
                4: "G123"
            }
        },
        "term": {
            "match": {
                1: "4 * 5",
                2: "20 / 4",
                3: "20 / 4 * 3"
            },
            "ast": {
                1: "(term (factor 4) (:Token *) (factor 5))",
                2: "(term (factor 20) (:Token /) (factor 4))",
                3: "(term (term (factor 20) (:Token /) (factor 4)) (:Token *) (factor 3))"
            },
            "fail": {
                4: "4 + 5",
                5: "20 / 4 - 3"
            }
        }
    }

    failure_cases = {
        "term": {
            "match": {
                1: "4 + 5",     # error: this should fail
                2: "20 / 4",
                3: "20 / 4 * 3"
            },
            "ast": {
                1: "(term (factor 4) (:Token *) (factor 5))",
                2: "(term (factor 20) (:Token /) (factor 4))",
                3: "(term (term (factor 19) (:Token /) (factor 4)) (:Token *) (factor 3))"  # error 19 != 20
            },
            "fail": {
                4: "4 * 5",     # error: this should match
                5: "20 / 4 - 3"
            }
        }
    }

    def test_testing_grammar(self):
        parser_fac = parser_factory(ARITHMETIC_EBNF)
        trans_fac = lambda : ARITHMETIC_EBNFTransform
        errata = parsers.test_grammar(self.cases, parser_fac, trans_fac)
        assert not errata, str(errata)
        errata = parsers.test_grammar(self.failure_cases, parser_fac, trans_fac)
        # for e in errata:
        #     print(e)
        assert len(errata) == 3

class TestInfiLoopsAndRecursion:
    def test_direct_left_recursion(self):
        minilang = ARITHMETIC_EBNF
        snippet = "5 + 3 * 4"
        parser = parser_factory(minilang)()
        assert parser
        syntax_tree = parser(snippet)
        assert not syntax_tree.collect_errors()
        assert snippet == str(syntax_tree)
        if is_logging():
            syntax_tree.log("test_LeftRecursion_direct.cst")
            # self.minilang_parser1.log_parsing_history("test_LeftRecursion_direct")

    def test_indirect_left_recursion(self):
        pass

    def test_inifinite_loops(self):
        minilang = """not_forever = { // } \n"""
        snippet = " "
        parser = parser_factory(minilang)()
        syntax_tree = parser(snippet)
        assert syntax_tree.error_flag
        # print(syntax_tree.collect_errors())


class TestRegex:
    def test_multilineRegex(self):
        mlregex = r"""
        regex =  /\w+    # one or more alphabetical characters including the underscore
                  [+]    # followed by a plus sign
                  \w*    # possibly followed by more alpha chracters/
        """
        result, messages, syntax_tree = compile_source(mlregex, None, get_ebnf_grammar(),
                        get_ebnf_transformer(), get_ebnf_compiler('MultilineRegexTest'))
        assert result
        assert not messages
        parser = compile_python_object(DHPARSER_IMPORTS + result, '\w+Grammar$')()
        node, rest = parser.regex('abc+def')
        assert rest == ''
        assert node.parser.name == "regex"
        assert str(node) == 'abc+def'

    def test_token(self):
        tokenlang = r"""
            @whitespace = linefeed
            lang        = "" begin_token {/\w+/ ""} end_token
            begin_token = "\begin{document}"
            end_token   = "\end{document}"
            """
        testdoc = r"""
            \begin{document}
            test
            \end{document}
            """
        result, messages, syntax_tree = compile_source(tokenlang, None, get_ebnf_grammar(),
                                    get_ebnf_transformer(), get_ebnf_compiler("TokenTest"))
        assert result
        assert not messages
        parser = compile_python_object(DHPARSER_IMPORTS + result, '\w+Grammar$')()
        result = parser(testdoc)
        # parser.log_parsing_history("test.log")
        assert not result.error_flag


if __name__ == "__main__":
    from run import runner
    runner("", globals())