test_parser.py

#!/usr/bin/python3

"""test_parser.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.
"""

import sys
from functools import partial

sys.path.extend(['../', './'])

from DHParser.toolkit import is_logging, logging, StringView, compile_python_object
from DHParser.parser import compile_source, Retrieve, Grammar, Forward, Token, ZeroOrMore, RE, \
    RegExp, Lookbehind, NegativeLookahead, OneOrMore, Series
from DHParser.ebnf import get_ebnf_grammar, get_ebnf_transformer, get_ebnf_compiler
from DHParser.dsl import grammar_provider, DHPARSER_IMPORTS


class TestInfiLoopsAndRecursion:
    def test_direct_left_recursion1(self):
        minilang =""" 
            @ whitespace = linefeed
            formula = [ //~ ] expr
            expr = expr ("+"|"-") term | term
            term = term ("*"|"/") factor | factor
            factor = /[0-9]+/~
            # example:  "5 + 3 * 4"
            """
        snippet = "9 + 8 + 7 + 6 + 5 + 3 * 4"
        parser = grammar_provider(minilang)()
        assert parser
        syntax_tree = parser(snippet)
        assert not syntax_tree.error_flag, str(syntax_tree.collect_errors())
        assert snippet == str(syntax_tree)
        if is_logging():
            syntax_tree.log("test_LeftRecursion_direct.cst")
            parser.log_parsing_history__("test_LeftRecursion_direct")

    def test_direct_left_recursion2(self):
        minilang = """
            @ whitespace = linefeed
            formula = [ //~ ] expr
            expr = ex
            ex   = expr ("+"|"-") term | term
            term = term ("*"|"/") factor | factor
            factor = /[0-9]+/~
            # example:  "5 + 3 * 4"
            """
        snippet = "9 + 8 + 7 + 6 + 5 + 3 * 4"
        parser = grammar_provider(minilang)()
        assert parser
        syntax_tree = parser(snippet)
        assert not syntax_tree.error_flag, syntax_tree.collect_errors()
        assert snippet == str(syntax_tree)

    def test_indirect_left_recursion1(self):
        minilang = """
            Expr    = //~ (Product | Sum | Value)
            Product = Expr { ('*' | '/') Expr }+
            Sum     = Expr { ('+' | '-') Expr }+
            Value   = /[0-9.]+/~ | '(' Expr ')'
            """
        parser = grammar_provider(minilang)()
        assert parser
        snippet = "8 * 4"
        syntax_tree = parser(snippet)
        assert not syntax_tree.error_flag, syntax_tree.collect_errors()
        snippet = "7 + 8 * 4"
        syntax_tree = parser(snippet)
        assert not syntax_tree.error_flag, syntax_tree.collect_errors()
        snippet = "9 + 8 * (4 + 3)"
        syntax_tree = parser(snippet)
        assert not syntax_tree.error_flag, syntax_tree.collect_errors()
        assert snippet == str(syntax_tree)

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


class TestFlowControl:
    def setup(self):
        self.t1 = """
        All work and no play 
        makes Jack a dull boy
        END
        """
        self.t2 = "All word and not play makes Jack a dull boy END\n"

    def test_lookbehind(self):
        ws = RegExp('\s*')
        end = RegExp("END")
        doc_end = Lookbehind(RegExp('\\s*?\\n')) + end
        word = RegExp('\w+')
        sequence = OneOrMore(NegativeLookahead(end) + word + ws)
        document = ws + sequence + doc_end + ws

        parser = Grammar(document)
        cst = parser(self.t1)
        assert not cst.error_flag, cst.as_sxpr()
        cst = parser(self.t2)
        assert cst.error_flag, cst.as_sxpr()

    def test_lookbehind_indirect(self):
        class LookbehindTestGrammar(Grammar):
            parser_initialization__ = "upon instantiation"
            ws = RegExp('\\s*')
            end = RegExp('END')
            SUCC_LB = RegExp('\\s*?\\n')
            doc_end = Series(Lookbehind(SUCC_LB), end)
            word = RegExp('\w+')
            sequence = OneOrMore(Series(NegativeLookahead(end), word, ws))
            document = Series(ws, sequence, doc_end, ws)
            root__ = document

        parser = LookbehindTestGrammar()
        cst = parser(self.t1)
        assert not cst.error_flag, cst.as_sxpr()
        cst = parser(self.t2)
        assert cst.error_flag, cst.as_sxpr()


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, str(messages)
        parser = compile_python_object(DHPARSER_IMPORTS + result, '\w+Grammar$')()
        node, rest = parser.regex(StringView('abc+def'))
        assert rest == ''
        assert node.parser.name == "regex"
        assert str(node) == 'abc+def'

    def text_ignore_case(self):
        mlregex = r"""
        @ ignorecase = True
        regex = /alpha/
        """
        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('Alpha')
        assert node
        assert not node.error_flag
        assert rest == ''
        assert node.parser.name == "regex"
        assert str(node) == 'Alpha'

        mlregex = r"""
        @ ignorecase = False
        regex = /alpha/
        """
        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('Alpha')
        assert node.error_flag


    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


class TestGrammar:
    def setup(self):
        grammar = r"""@whitespace = horizontal
        haupt        = textzeile LEERZEILE
        textzeile    = { WORT }+
        WORT         = /[^ \t]+/~
        LEERZEILE    = /\n[ \t]*(?=\n)/~
        """
        self.pyparser, messages, syntax_tree = compile_source(grammar, None, get_ebnf_grammar(),
                                                              get_ebnf_transformer(), get_ebnf_compiler("PosTest"))
        assert self.pyparser
        assert not messages

    def test_pos_values_initialized(self):
        # checks whether pos values in the parsing result and in the
        # history record have been initialized
        with logging("LOGS"):
            grammar = compile_python_object(DHPARSER_IMPORTS + self.pyparser, '\w+Grammar$')()
            grammar("no_file_name*")
        for record in grammar.history__:
            assert not record.node or record.node.pos >= 0

    def test_select_parsing(self):
        grammar = compile_python_object(DHPARSER_IMPORTS + self.pyparser, '\w+Grammar$')()
        grammar("wort", "WORT")
        grammar("eine Zeile", "textzeile")
        grammar("kein Haupt", "haupt")
        grammar("so ist es richtig", "haupt")

    def test_grammar_subclassing(self):
        class Arithmetic(Grammar):
            '''
            expression =  term  { ("+" | "-") term }
            term       =  factor  { ("*" | "/") factor }
            factor     =  INTEGER | "("  expression  ")"
            INTEGER    =  /\d+/~
            '''
            expression = Forward()
            INTEGER = RE('\\d+')
            factor = INTEGER | Token("(") + expression + Token(")")
            term = factor + ZeroOrMore((Token("*") | Token("/")) + factor)
            expression.set(term + ZeroOrMore((Token("+") | Token("-")) + term))
            root__ = expression

        grammar = Arithmetic()
        CST = grammar('3+4')
        assert not CST.error_flag, CST.as_sxpr()


class TestPopRetrieve:
    mini_language = """
        document       = { text | codeblock }
        codeblock      = delimiter { text | (!:delimiter delimiter_sign) } ::delimiter
        delimiter      = delimiter_sign  # never use delimiter between capture and pop except for retrival!
        delimiter_sign = /`+/
        text           = /[^`]+/ 
        """
    mini_lang2 = """
        @braces_filter=counterpart
        document       = { text | codeblock }
        codeblock      = braces { text | opening_braces | (!:braces closing_braces) } ::braces
        braces         = opening_braces
        opening_braces = /\{+/
        closing_braces = /\}+/
        text           = /[^{}]+/
        """
    mini_lang3 = """
        document       = { text | env }
        env            = (specialtag | opentag) text [closespecial | closetag]
        opentag        = "<" name ">"
        specialtag     = "<" /ABC/ !name ">"
        closetag       = close_slash | close_star 
        close_slash    = "<" ::name "/>"
        close_star     = "<" ::name "*>"
        closespecial   = "<" /ABC/~ ">"
        name           = /\w+/~
        text           = /[^<>]+/
        """

    def setup(self):
        self.minilang_parser = grammar_provider(self.mini_language)()
        self.minilang_parser2 = grammar_provider(self.mini_lang2)()
        self.minilang_parser3 = grammar_provider(self.mini_lang3)()

    @staticmethod
    def opening_delimiter(node, name):
        return node.tag_name == name and not isinstance(node.parser, Retrieve)

    @staticmethod
    def closing_delimiter(node):
        return isinstance(node.parser, Retrieve)

    def test_compile_mini_language(self):
        assert self.minilang_parser
        assert self.minilang_parser2
        assert self.minilang_parser3

    def test_stackhandling(self):
        ambigous_opening = "<ABCnormal> normal tag <ABCnormal*>"
        syntax_tree = self.minilang_parser3(ambigous_opening)
        assert not syntax_tree.error_flag, str(syntax_tree.collect_errors())

        ambigous_opening = "<ABCnormal> normal tag <ABCnormal/>"
        syntax_tree = self.minilang_parser3(ambigous_opening)
        assert not syntax_tree.error_flag, str(syntax_tree.collect_errors())

        forgot_closing_tag = "<em> where is the closing tag?"
        syntax_tree = self.minilang_parser3(forgot_closing_tag)
        assert syntax_tree.error_flag, str(syntax_tree.collect_errors())

        proper = "<em> has closing tag <em/>"
        syntax_tree = self.minilang_parser3(proper)
        assert not syntax_tree.error_flag, str(syntax_tree.collect_errors())

        proper = "<em> has closing tag <em*>"
        syntax_tree = self.minilang_parser3(proper)
        assert not syntax_tree.error_flag, str(syntax_tree.collect_errors())

    def test_cache_neutrality(self):
        """Test that packrat-caching does not interfere with the variable-
        changing parsers: Capture and Retrieve."""
        lang = """
            text = opening closing
            opening = (unmarked_package | marked_package)
            closing = ::variable
            unmarked_package = package "."
            marked_package = package "*" "."
            package = "(" variable ")"
            variable = /\w+/~
            """
        case = "(secret)*. secret"
        gr = grammar_provider(lang)()
        st = gr(case)
        assert not st.error_flag, str(st.collect_errors())

    def test_single_line(self):
        teststr = "Anfang ```code block `` <- keine Ende-Zeichen ! ``` Ende"
        syntax_tree = self.minilang_parser(teststr)
        assert not syntax_tree.collect_errors()
        delim = str(next(syntax_tree.find(partial(self.opening_delimiter, name="delimiter"))))
        pop = str(next(syntax_tree.find(self.closing_delimiter)))
        assert delim == pop
        if is_logging():
            syntax_tree.log("test_PopRetrieve_single_line.cst")

    def test_multi_line(self):
        teststr = """
            Anfang ```code block `` <- keine Ende-Zeichen ! ``` Ebde

            Absatz ohne ``` codeblock, aber
            das stellt sich erst am Ende herause...

            Mehrzeliger ```code block
            """
        syntax_tree = self.minilang_parser(teststr)
        assert not syntax_tree.collect_errors()
        delim = str(next(syntax_tree.find(partial(self.opening_delimiter, name="delimiter"))))
        pop = str(next(syntax_tree.find(self.closing_delimiter)))
        assert delim == pop
        if is_logging():
            syntax_tree.log("test_PopRetrieve_multi_line.cst")

    def test_single_line_complement(self):
        teststr = "Anfang {{{code block }} <- keine Ende-Zeichen ! }}} Ende"
        syntax_tree = self.minilang_parser2(teststr)
        assert not syntax_tree.collect_errors()
        delim = str(next(syntax_tree.find(partial(self.opening_delimiter, name="braces"))))
        pop = str(next(syntax_tree.find(self.closing_delimiter)))
        assert len(delim) == len(pop) and delim != pop
        if is_logging():
            syntax_tree.log("test_PopRetrieve_single_line.cst")

    def test_multi_line_complement(self):
        teststr = """
            Anfang {{{code block {{ <- keine Ende-Zeichen ! }}} Ende

            Absatz ohne {{{ codeblock, aber
            das stellt sich erst am Ende heraus...

            Mehrzeliger }}}code block
            """
        syntax_tree = self.minilang_parser2(teststr)
        assert not syntax_tree.collect_errors()
        delim = str(next(syntax_tree.find(partial(self.opening_delimiter, name="braces"))))
        pop = str(next(syntax_tree.find(self.closing_delimiter)))
        assert len(delim) == len(pop) and delim != pop
        if is_logging():
            syntax_tree.log("test_PopRetrieve_multi_line.cst")


class TestWhitespaceHandling:
    minilang = """@testing = True
        doc = A B
        A = "A"
        B = "B"
        Rdoc = ar br
        ar = /A/
        br = /B/
        """

    def setup(self):
        self.gr = grammar_provider(self.minilang)()

    def test_token_whitespace(self):
        st = self.gr("AB", 'doc')
        assert not st.error_flag
        st = self.gr("A B", 'doc')
        assert not st.error_flag

    def test_regexp_whitespace(self):
        st = self.gr("AB", 'Rdoc')
        assert not st.error_flag
        st = self.gr("A B", 'Rdoc')
        assert st.error_flag


class TestBorderlineCases:
    def test_not_matching(self):
        minilang = """parser = /X/"""
        gr = grammar_provider(minilang)()
        cst = gr('X', 'parser')
        assert not cst.error_flag
        cst = gr(' ', 'parser')
        assert cst.error_flag
        cst = gr('', 'parser')
        assert cst.error_flag

    def test_matching(self):
        minilang = """parser = /.?/"""
        gr = grammar_provider(minilang)()
        cst = gr(' ', 'parser')
        assert not cst.error_flag
        cst = gr('  ', 'parser')
        assert cst.error_flag
        cst = gr('', 'parser')
        assert not cst.error_flag


if __name__ == "__main__":
    from DHParser.testing import runner
    with logging(True):
        runner("TestInfiLoopsAndRecursion.test_direct_left_recursion1", globals())