test_preprocess.py

#!/usr/bin/env python3

"""test_preprocess.py - tests of the preprocessor-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 os
import sys

scriptpath = os.path.dirname(__file__) or '.'
sys.path.append(os.path.abspath(os.path.join(scriptpath, '..')))

from functools import partial

from DHParser.configuration import set_config_value
from DHParser.dsl import grammar_provider
from DHParser import compile_source
from DHParser.preprocess import make_token, tokenized_to_original_mapping, source_map, \
    BEGIN_TOKEN, END_TOKEN, TOKEN_DELIMITER, SourceMapFunc, SourceMap, chain_preprocessors, \
    strip_tokens
from DHParser.toolkit import lstrip_docstring, typing
from typing import Tuple


class TestMakeToken:
    def test_make_token1(self):
        tk = make_token("INDENTED_BLOCK", " " * 4)
        assert tk[0] == BEGIN_TOKEN
        assert tk[-1] == END_TOKEN
        d = tk.find(TOKEN_DELIMITER)
        assert 0 < d < len(tk) - 1
        assert tk[1:d] == "INDENTED_BLOCK"
        assert tk[d + 1:-1] == " " * 4

    def test_make_token2(self):
        tk = make_token("EMPTY_TOKEN")
        assert tk[0] == BEGIN_TOKEN
        assert tk[-1] == END_TOKEN
        d = tk.find(TOKEN_DELIMITER)
        assert 0 < d < len(tk) - 1
        assert tk[1:d] == "EMPTY_TOKEN"
        assert tk[d + 1:-1] == ""


class TestSourceMapping:
    code = "All persons are mortal AND Socrates is a person YIELDS Socrates is mortal"
    tokenized = code.replace('AND', make_token('CONJUNCTION', 'AND')) \
        .replace('YIELDS', make_token('IMPLICATION', 'YIELDS'))


    def test_tokenized_to_original_mapping(self):
        srcmap = tokenized_to_original_mapping(self.tokenized)
        positions, offsets = srcmap.positions, srcmap.offsets
        assert len(positions) == len(offsets)
        assert positions[0] == 0
        assert all(positions[i] < positions[i + 1] for i in range(len(positions) - 1))
        assert all(offsets[i] > offsets[i + 1] for i in range(len(offsets) - 2))
        assert offsets[-1] >= offsets[-2]
        assert self.tokenized.find('AND') == self.code.find('AND') + len('CONJUNCTION') + 2

    def test_bondary_cases(self):
        # position at the end of the file
        source = " "
        srcmap = tokenized_to_original_mapping(source)
        pos = source_map(1, srcmap)
        # empty file
        source =""
        srcmap = tokenized_to_original_mapping(source)
        pos = source_map(0, srcmap)


def preprocess_indentation(src: str) -> str:
    transformed = []
    indent_level = 0
    for line in src.split('\n'):
        indent = len(line) - len(line.lstrip()) if line.strip() else indent_level * 4
        assert indent % 4 == 0
        if indent > indent_level * 4:
            assert indent == (indent_level + 1) * 4, str(indent)  # indent must be 4 spaces
            indent_level += 1
            line = make_token('BEGIN_INDENT') + line
        elif indent <= (indent_level - 1) * 4:
            while indent <= (indent_level - 1) * 4:
                line = make_token('END_INDENT') + line
                indent_level -= 1
            assert indent == (indent_level + 1) * 4  # indent must be 4 spaces
        else:
            assert indent == indent_level * 4
        transformed.append(line)
    while indent_level > 0:
        transformed[-1] += make_token('END_INDENT')
        indent_level -= 1
    tokenized = '\n'.join(transformed)
    # print(prettyprint_tokenized(tokenized))
    return tokenized

def preprocess_comments(src: str) -> Tuple[str, SourceMapFunc]:
    lines = src.split('\n')
    positions, offsets = [0], [0]
    pos = 0
    for i, line in enumerate(lines):
        comment_pos = line.find('#')
        if comment_pos >= 0:
            pos += comment_pos
            lines[i] = line[:comment_pos]
            positions.append(pos - offsets[-1])
            offsets.append(offsets[-1] + len(line) - comment_pos)
        pos += len(lines[i])
    positions.append(pos)
    offsets.append(offsets[-1])
    return '\n'.join(lines), partial(source_map, srcmap=SourceMap(positions, offsets))


class TestTokenParsing:
    ebnf = r"""
        @ tokens     = BEGIN_INDENT, END_INDENT
        @ whitespace = /[ \t]*/ 
        block       = { line | indentBlock }+
        line        = ~/[^\x1b\x1c\x1d\n]*\n/
        indentBlock = BEGIN_INDENT block END_INDENT
        """
    set_config_value('max_parser_dropouts', 3)
    grammar = grammar_provider(ebnf)()
    code = lstrip_docstring("""
        def func(x, y):
            if x > 0:         # a comment
                if y > 0:
                    print(x)  # another comment
                    print(y)
        """)
    tokenized = preprocess_indentation(code)
    srcmap = tokenized_to_original_mapping(tokenized)

    def verify_mapping(self, teststr, orig_text, preprocessed_text, mapping):
        mapped_pos = preprocessed_text.find(teststr)
        assert mapped_pos >= 0
        original_pos = mapping(mapped_pos)
        # original_pos = source_map(mapped_pos, self.srcmap)
        assert orig_text[original_pos:original_pos + len(teststr)] == teststr, \
            '"%s" (%i) wrongly mapped onto "%s" (%i)' % \
            (teststr, mapped_pos, orig_text[original_pos:original_pos + len(teststr)], original_pos)

    def test_strip_tokens(self):
        assert self.code == strip_tokens(self.tokenized)

    def test_parse_tokenized(self):
        cst = self.grammar(self.tokenized)
        assert not cst.error_flag

    def test_source_mapping_1(self):
        mapping = partial(source_map, srcmap=self.srcmap)
        self.verify_mapping("def func", self.code, self.tokenized, mapping)
        self.verify_mapping("x > 0:", self.code, self.tokenized, mapping)
        self.verify_mapping("if y > 0:", self.code, self.tokenized, mapping)
        self.verify_mapping("print(x)", self.code, self.tokenized, mapping)
        self.verify_mapping("print(y)", self.code, self.tokenized, mapping)

    def test_source_mapping_2(self):
        previous_index = 0
        L = len(self.code)
        for mapped_index in range(len(self.tokenized)):
            index = source_map(mapped_index, self.srcmap)
            assert previous_index <= index <= L, \
                "%i <= %i <= %i violated" % (previous_index, index, L)
            previous_index = index

    def test_non_token_preprocessor(self):
        tokenized, mapping = preprocess_comments(self.code)
        self.verify_mapping("def func", self.code, tokenized, mapping)
        self.verify_mapping("x > 0:", self.code, tokenized, mapping)
        self.verify_mapping("if y > 0:", self.code, tokenized, mapping)
        self.verify_mapping("print(x)", self.code, tokenized, mapping)
        self.verify_mapping("print(y)", self.code, tokenized, mapping)

    def test_chained_preprocessors(self):
        pchain = chain_preprocessors(preprocess_comments, preprocess_indentation)
        tokenized, mapping = pchain(self.code)
        self.verify_mapping("def func", self.code, tokenized, mapping)
        self.verify_mapping("x > 0:", self.code, tokenized, mapping)
        self.verify_mapping("if y > 0:", self.code, tokenized, mapping)
        self.verify_mapping("print(x)", self.code, tokenized, mapping)
        self.verify_mapping("print(y)", self.code, tokenized, mapping)

    def test_error_position(self):
        orig_src = self.code.replace('#', '\x1b')
        prepr = chain_preprocessors(preprocess_comments, preprocess_indentation)
        self.grammar.max_parser_dropouts__ = 3
        result, messages, syntaxtree = compile_source(orig_src, prepr, self.grammar,
                                                      lambda i: i, lambda i: i)
        for err in messages:
            if self.code[err.orig_pos] == "#":
                break
        else:
            assert False, "wrong error positions"


if __name__ == "__main__":
    # tp = TestTokenParsing()
    # tp.setup()
    from DHParser.testing import runner

    runner("", globals())