- cstringview finished (some (enough?) optimizations)

DHParser/VERALTET/cstringview.pyx

+"""cstringview.pyx - a cython-version of the stringview class for speedup
+                     slicing strings without copying
+
+Copyright 2016  by Eckhart Arnold (arnold@badw.de)
+                Bavarian Academy of Sciences an Humanities (badw.de)
+
+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.
+
+StringView provides string-slicing without copying.
+Slicing Python-strings always yields copies of a segment of the original
+string. See: https://mail.python.org/pipermail/python-dev/2008-May/079699.html
+However, this becomes costly (in terms of space and as a consequence also
+time) when parsing longer documents. Unfortunately, Python's `memoryview`
+does not work for unicode strings. Hence, the StringView class.
+"""
+
+import collections
+from typing import Optional, Iterable, Tuple
+
+__all__ = ('StringView', 'EMPTY_STRING_VIEW')
+
+
+cdef struct Range:
+    int begin
+    int end
+
+
+cdef inline int pack_index(int index, int len):
+    index = index if index >= 0 else index + len
+    return 0 if index < 0 else len if index > len else index
+
+
+cdef Range real_indices(begin, end, int len):
+    cdef int ibegin = 0
+    cdef int iend = len
+    if begin is not None:  ibegin = begin
+    if end is not None:  iend = end
+    cdef Range r
+    r.begin = pack_index(ibegin, len)
+    r.end = pack_index(iend, len)
+    return r
+
+
+class StringView(collections.abc.Sized):
+    """"
+    A rudimentary StringView class, just enough for the use cases
+    in parser.py. The difference between a StringView and the python
+    builtin strings is that StringView-objects do slicing without
+    copying, i.e. slices are just a view on a section of the sliced
+    string.
+    """
+
+    __slots__ = ['text', 'begin', 'end', 'len', 'fullstring_flag']
+
+    def __init__(self, text: str, begin: Optional[int] = 0, end: Optional[int] = None) -> None:
+        self.text = text  # type: str
+        self.begin = 0  # type: int
+        self.end = 0  # type: int
+        cdef Range r = real_indices(begin, end, len(text))
+        self.begin = r.begin
+        self.end = r.end
+        self.len = max(self.end - self.begin, 0)
+        self.fullstring_flag = (self.begin == 0 and self.len == len(self.text))
+
+    def __bool__(self):
+        return self.end > self.begin  # and bool(self.text)
+
+    def __len__(self):
+        return self.len
+
+    def __str__(self):
+        if self.fullstring_flag:  # optimization: avoid slicing/copying
+            return self.text
+        # since the slice is being copyied now, anyway, the copy might
+        # as well be stored in the string view
+        self.text = self.text[self.begin:self.end]
+        self.begin = 0
+        self.len = len(self.text)
+        self.end = self.len
+        self.fullstring_flag = True
+        return self.text
+
+    def __eq__(self, other):
+        return len(other) == len(self) and str(self) == str(other)  # PERFORMANCE WARNING: This creates copies of the strings
+
+    def __hash__(self):
+        return hash(str(self))  # PERFORMANCE WARNING: This creates a copy of the string-slice
+
+    def __add__(self, other):
+        if isinstance(other, str):
+            return (str(self) + other)
+        else:
+            return StringView(str(self) + str(other))
+
+    def __radd__(self, other):
+        if isinstance(other, str):
+            return (other + str(self))
+        else:
+            return StringView(str(other) + str(self))
+
+    def __getitem__(self, index):
+        # assert isinstance(index, slice), "As of now, StringView only allows slicing."
+        # assert index.step is None or index.step == 1, \
+        #     "Step sizes other than 1 are not yet supported by StringView"
+        cdef Range r = real_indices(index.start, index.stop, self.len)
+        start = r.begin;  stop = r.end
+        return StringView(self.text, self.begin + start, self.begin + stop)
+
+    def count(self, sub, start=None, end=None) -> int:
+        cdef Range r
+        if self.fullstring_flag:
+            return self.text.count(sub, start, end)
+        elif start is None and end is None:
+            return self.text.count(sub, self.begin, self.end)
+        else:
+            r = real_indices(start, end, self.len)
+            start = r.begin; end = r.end
+            return self.text.count(sub, self.begin + start, self.begin + end)
+
+    def find(self, sub, start=None, end=None) -> int:
+        cdef Range r
+        if self.fullstring_flag:
+            return self.text.find(sub, start, end)
+        elif start is None and end is None:
+            return self.text.find(sub, self.begin, self.end) - self.begin
+        else:
+            r = real_indices(start, end, self.len)
+            start = r.begin; end = r.end
+            return self.text.find(sub, self.begin + start, self.begin + end) - self.begin
+
+    def rfind(self, sub, start=None, end=None) -> int:
+        cdef Range r
+        if self.fullstring_flag:
+            return self.text.rfind(sub, start, end)
+        if start is None and end is None:
+            return self.text.rfind(sub, self.begin, self.end) - self.begin
+        else:
+            r = real_indices(start, end, self.len)
+            start = r.begin; end = r.end
+            return self.text.rfind(sub, self.begin + start, self.begin + end) - self.begin
+
+    def startswith(self, prefix: str, start: int = 0, end: Optional[int] = None) -> bool:
+        start += self.begin
+        end = self.end if end is None else self.begin + end
+        return self.text.startswith(prefix, start, end)
+
+    def match(self, regex):
+        return regex.match(self.text, pos=self.begin, endpos=self.end)
+
+    def index(self, absolute_index: int) -> int:
+        """
+        Converts an index for a string watched by a StringView object
+        to an index relative to the string view object, e.g.:
+        >>> sv = StringView('xxIxx')[2:3]
+        >>> match = sv.match(re.compile('I'))
+        >>> match.end()
+        3
+        >>> sv.index(match.end())
+        1
+        """
+        return absolute_index - self.begin
+
+    def indices(self, absolute_indices: Iterable[int]) -> Tuple[int, ...]:
+        """Converts indices for a string watched by a StringView object
+        to indices relative to the string view object. See also: `sv_index()`
+        """
+        return tuple(index - self.begin for index in absolute_indices)
+
+    def search(self, regex):
+        return regex.search(self.text, pos=self.begin, endpos=self.end)
+
+    def strip(self):
+        if self.fullstring_flag:
+            return self.text.strip()
+        else:
+            begin = self.begin
+            end = self.end
+            while begin < end and self.text[begin] in ' \n\t':
+                begin += 1
+            while end > begin and self.text[end] in ' \n\t':
+                end -= 1
+            return self.text[begin:end]
+        # return str(self).strip()  # PERFORMANCE WARNING: This creates a copy of the string
+
+    def split(self, sep=None):
+        if self.fullstring_flag:
+            return self.text.split(sep)
+        else:
+            pieces = []
+            l = len(sep)
+            k = 0
+            i = self.find(sep, k)
+            while i >= 0:
+                pieces.append(self.text[self.begin + k : self.begin + i])
+                k = i + l
+                i = self.find(sep, k)
+            pieces.append(self.text[self.begin + k : self.end])
+            return pieces
+        # return str(self).split(sep, maxsplit)  # PERFORMANCE WARNING: This creates a copy of the string
+
+
+EMPTY_STRING_VIEW = StringView('')

DHParser/cstringview.pyx

@@ -29,12 +29,12 @@ from typing import Optional, Iterable, Tuple
 __all__ = ('StringView', 'EMPTY_STRING_VIEW')
 
 
-def pack_index(index, len):
+cdef inline int pack_index(int index, int len):
     index = index if index >= 0 else index + len
     return 0 if index < 0 else len if index > len else index
 
 
-def real_indices(begin, end, len):
+cdef real_indices(begin, end, len):
     if begin is None:  begin = 0
     if end is None:  end = len
     return pack_index(begin, len), pack_index(end, len)
@@ -78,10 +78,10 @@ class StringView(collections.abc.Sized):
         return self.text
 
     def __eq__(self, other):
-        return str(self) == str(other)  # PERFORMANCE WARNING: This creates copies of the strings
+        return len(other) == len(self) and str(self) == str(other)  # PERFORMANCE WARNING: This creates copies of the strings
 
     def __hash__(self):
-        return hash(str(self))  # PERFORMANCE WARNING: This creates a copy of the string
+        return hash(str(self))  # PERFORMANCE WARNING: This creates a copy of the string-slice
 
     def __add__(self, other):
         if isinstance(other, str):

DHParser/dsl.py

@@ -21,23 +21,17 @@ compilation of domain specific languages based on an EBNF-grammar.
 
 import os
 
-try:
-    import regex as re
-except ImportError:
-    import re
-try:
-    from typing import Any, cast, Tuple, Union, Iterator, Iterable
-except ImportError:
-    from .typing34 import Any, cast, Tuple, Union, Iterator, Iterable
-
 from DHParser.ebnf import EBNFCompiler, grammar_changed, \
     get_ebnf_preprocessor, get_ebnf_grammar, get_ebnf_transformer, get_ebnf_compiler, \
     PreprocessorFactoryFunc, ParserFactoryFunc, TransformerFactoryFunc, CompilerFactoryFunc
-from DHParser.toolkit import logging, load_if_file, is_python_code, compile_python_object
+from DHParser.toolkit import logging, load_if_file, is_python_code, compile_python_object, \
+    re, typing
 from DHParser.parser import Grammar, Compiler, compile_source, nil_preprocessor, PreprocessorFunc
 from DHParser.syntaxtree import Node, TransformationFunc
 from DHParser.error import Error, is_error, has_errors, only_errors
 
+from typing import Any, cast, Tuple, Union, Iterator, Iterable
+
 __all__ = ('GrammarError',
            'CompilationError',
            'load_compiler_suite',

DHParser/ebnf.py

@@ -20,16 +20,7 @@ import keyword
 from collections import OrderedDict
 from functools import partial
 
-try:
-    import regex as re
-except ImportError:
-    import re
-try:
-    from typing import Callable, Dict, List, Set, Tuple, Union
-except ImportError:
-    from .typing34 import Callable, Dict, List, Set, Tuple, Union
-
-from DHParser.toolkit import load_if_file, escape_re, md5, sane_parser_name
+from DHParser.toolkit import load_if_file, escape_re, md5, sane_parser_name, re, typing
 from DHParser.parser import Grammar, mixin_comment, nil_preprocessor, Forward, RegExp, RE, \
     NegativeLookahead, Alternative, Series, Option, OneOrMore, ZeroOrMore, Token, \
     Required, Compiler, PreprocessorFunc
@@ -40,6 +31,8 @@ from DHParser.transform import traverse, remove_brackets, \
     remove_tokens, flatten, forbid, assert_content, remove_infix_operator
 from DHParser.versionnumber import __version__
 
+from typing import Callable, Dict, List, Set, Tuple, Union
+
 __all__ = ('get_ebnf_preprocessor',
            'get_ebnf_grammar',
            'get_ebnf_transformer',

DHParser/parser.py

@@ -61,29 +61,13 @@ import copy
 import os
 from functools import partial
 
-try:
-    import regex as re
-except ImportError:
-    import re
-try:
-    from typing import Any, Callable, cast, Dict, Iterator, List, Set, Tuple, Union, Optional
-    # try:
-    #     from typing import Collection
-    # except ImportError:
-    #     pass
-except ImportError:
-    from .typing34 import Any, Callable, cast, Dict, Iterator, List, Set, Tuple, Union, Optional
-
-from DHParser.toolkit import is_logging, log_dir, logfile_basename, escape_re, sane_parser_name
+from DHParser.toolkit import is_logging, log_dir, logfile_basename, escape_re, sane_parser_name, load_if_file, \
+        re, typing
+from DHParser.stringview import StringView, EMPTY_STRING_VIEW
 from DHParser.syntaxtree import Node, TransformationFunc, ParserBase, WHITESPACE_PTYPE, TOKEN_PTYPE, \
     ZOMBIE_PARSER
 from DHParser.error import Error, is_error, has_errors, linebreaks, line_col
-from DHParser.toolkit import load_if_file
-try:
-    import pyximport; pyximport.install()
-    from DHParser.cstringview import StringView, EMPTY_STRING_VIEW
-except ImportError:
-    from DHParser.stringview import StringView, EMPTY_STRING_VIEW
+from typing import Any, Callable, cast, Dict, Iterator, List, Set, Tuple, Union, Optional
 
 __all__ = ('PreprocessorFunc',
            'HistoryRecord',

DHParser/pstringview.py

+"""cstringview.pyx - a cython-version of the stringview class for speedup
+                     slicing strings without copying
+
+Copyright 2016  by Eckhart Arnold (arnold@badw.de)
+                Bavarian Academy of Sciences an Humanities (badw.de)
+
+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.
+
+StringView provides string-slicing without copying.
+Slicing Python-strings always yields copies of a segment of the original
+string. See: https://mail.python.org/pipermail/python-dev/2008-May/079699.html
+However, this becomes costly (in terms of space and as a consequence also
+time) when parsing longer documents. Unfortunately, Python's `memoryview`
+does not work for unicode strings. Hence, the StringView class.
+"""
+import collections
+from typing import Optional, Iterable, Tuple
+
+__all__ = ('StringView', 'EMPTY_STRING_VIEW')
+
+
+def pack_index(index, len):
+    index = index if index >= 0 else index + len
+    return 0 if index < 0 else len if index > len else index
+
+
+def real_indices(begin, end, len):
+    if begin is None:  begin = 0
+    if end is None:  end = len
+    return pack_index(begin, len), pack_index(end, len)
+
+
+class StringView(collections.abc.Sized):
+    """"
+    A rudimentary StringView class, just enough for the use cases
+    in parser.py. The difference between a StringView and the python
+    builtin strings is that StringView-objects do slicing without
+    copying, i.e. slices are just a view on a section of the sliced
+    string.
+    """
+
+    __slots__ = ['text', 'begin', 'end', 'len', 'fullstring_flag']
+
+    def __init__(self, text: str, begin: Optional[int] = 0, end: Optional[int] = None) -> None:
+        self.text = text  # type: str
+        self.begin = 0  # type: int
+        self.end = 0  # type: int
+        self.begin, self.end = real_indices(begin, end, len(text))
+        self.len = max(self.end - self.begin, 0)
+        self.fullstring_flag = (self.begin == 0 and self.len == len(self.text))
+
+    def __bool__(self):
+        return self.end > self.begin  # and bool(self.text)
+
+    def __len__(self):
+        return self.len
+
+    def __str__(self):
+        if self.fullstring_flag:  # optimization: avoid slicing/copying
+            return self.text
+        # since the slice is being copyied now, anyway, the copy might
+        # as well be stored in the string view
+        self.text = self.text[self.begin:self.end]
+        self.begin = 0
+        self.len = len(self.text)
+        self.end = self.len
+        self.fullstring_flag = True
+        return self.text
+
+    def __eq__(self, other):
+        return len(other) == len(self) and str(self) == str(other)  # PERFORMANCE WARNING: This creates copies of the strings
+
+    def __hash__(self):
+        return hash(str(self))  # PERFORMANCE WARNING: This creates a copy of the string-slice
+
+    def __add__(self, other):
+        if isinstance(other, str):
+            return (str(self) + other)
+        else:
+            return StringView(str(self) + str(other))
+
+    def __radd__(self, other):
+        if isinstance(other, str):
+            return (other + str(self))
+        else:
+            return StringView(str(other) + str(self))
+
+    def __getitem__(self, index):
+        # assert isinstance(index, slice), "As of now, StringView only allows slicing."
+        # assert index.step is None or index.step == 1, \
+        #     "Step sizes other than 1 are not yet supported by StringView"
+        start, stop = real_indices(index.start, index.stop, self.len)
+        return StringView(self.text, self.begin + start, self.begin + stop)
+
+    def count(self, sub, start=None, end=None) -> int:
+        if self.fullstring_flag:
+            return self.text.count(sub, start, end)
+        elif start is None and end is None:
+            return self.text.count(sub, self.begin, self.end)
+        else:
+            start, end = real_indices(start, end, self.len)
+            return self.text.count(sub, self.begin + start, self.begin + end)
+
+    def find(self, sub, start=None, end=None) -> int:
+        if self.fullstring_flag:
+            return self.text.find(sub, start, end)
+        elif start is None and end is None:
+            return self.text.find(sub, self.begin, self.end) - self.begin
+        else:
+            start, end = real_indices(start, end, self.len)
+            return self.text.find(sub, self.begin + start, self.begin + end) - self.begin
+
+    def rfind(self, sub, start=None, end=None) -> int:
+        if self.fullstring_flag:
+            return self.text.rfind(sub, start, end)
+        if start is None and end is None:
+            return self.text.rfind(sub, self.begin, self.end) - self.begin
+        else:
+            start, end = real_indices(start, end, self.len)
+            return self.text.rfind(sub, self.begin + start, self.begin + end) - self.begin
+
+    def startswith(self, prefix: str, start: int = 0, end: Optional[int] = None) -> bool:
+        start += self.begin
+        end = self.end if end is None else self.begin + end
+        return self.text.startswith(prefix, start, end)
+
+    def match(self, regex):
+        return regex.match(self.text, pos=self.begin, endpos=self.end)
+
+    def index(self, absolute_index: int) -> int:
+        """
+        Converts an index for a string watched by a StringView object
+        to an index relative to the string view object, e.g.:
+        >>> sv = StringView('xxIxx')[2:3]
+        >>> match = sv.match(re.compile('I'))
+        >>> match.end()
+        3
+        >>> sv.index(match.end())
+        1
+        """
+        return absolute_index - self.begin
+
+    def indices(self, absolute_indices: Iterable[int]) -> Tuple[int, ...]:
+        """Converts indices for a string watched by a StringView object
+        to indices relative to the string view object. See also: `sv_index()`
+        """
+        return tuple(index - self.begin for index in absolute_indices)
+
+    def search(self, regex):
+        return regex.search(self.text, pos=self.begin, endpos=self.end)
+
+    def strip(self):
+        if self.fullstring_flag:
+            return self.text.strip()
+        else:
+            begin = self.begin
+            end = self.end
+            while begin < end and self.text[begin] in ' \n\t':
+                begin += 1
+            while end > begin and self.text[end] in ' \n\t':
+                end -= 1
+            return self.text[begin:end]
+        # return str(self).strip()  # PERFORMANCE WARNING: This creates a copy of the string
+
+    def split(self, sep=None):
+        if self.fullstring_flag:
+            return self.text.split(sep)
+        else:
+            pieces = []
+            l = len(sep)
+            k = 0
+            i = self.find(sep, k)
+            while i >= 0:
+                pieces.append(self.text[self.begin + k : self.begin + i])
+                k = i + l
+                i = self.find(sep, k)
+            pieces.append(self.text[self.begin + k : self.end])
+            return pieces
+        # return str(self).split(sep, maxsplit)  # PERFORMANCE WARNING: This creates a copy of the string
+
+
+EMPTY_STRING_VIEW = StringView('')

DHParser/stringview.py

 """stringview.py - a stringview class: slicing strings without copying
+    (This module merely passes through the Python or Cython version of
+    string views. The real implementations are to be found in the
+    pstringview.py and cstringview.pyx modules, respectively.)
 
 Copyright 2016  by Eckhart Arnold (arnold@badw.de)
                 Bavarian Academy of Sciences an Humanities (badw.de)
@@ -27,114 +30,9 @@ from typing import Optional, Iterable, Tuple
 
 __all__ = ('StringView', 'EMPTY_STRING_VIEW')
 
+try:
+    import pyximport; pyximport.install()
+    from DHParser.cstringview import StringView, EMPTY_STRING_VIEW
+except ImportError:
+    from DHParser.pstringview import StringView, EMPTY_STRING_VIEW
 
-def pack_index(index, len):
-    index = index if index >= 0 else index + len
-    return 0 if index < 0 else len if index > len else index
-
-
-def real_indices(begin, end, len):
-    if begin is None:  begin = 0
-    if end is None:  end = len
-    return pack_index(begin, len), pack_index(end, len)
-
-
-class StringView(collections.abc.Sized):
-    """"
-    A rudimentary StringView class, just enough for the use cases
-    in parser.py. The difference between a StringView and the python
-    builtin strings is that StringView-objects do slicing without
-    copying, i.e. slices are just a view on a section of the sliced
-    string.
-    """
-
-    __slots__ = ['text', 'begin', 'end', 'len', 'fullstring_flag']
-
-    def __init__(self, text: str, begin: Optional[int] = 0, end: Optional[int] = None) -> None:
-        self.text = text  # type: str
-        self.begin = 0  # type: int
-        self.end = 0  # type: int
-        self.begin, self.end = real_indices(begin, end, len(text))
-        self.len = max(self.end - self.begin, 0)
-        self.fullstring_flag = (self.begin == 0 and self.len == len(self.text))
-
-    def __bool__(self):
-        return bool(self.text) and self.end > self.begin
-
-    def __len__(self):
-        return self.len
-
-    def __str__(self):
-        if self.fullstring_flag:  # optimization: avoid slicing/copying
-            return self.text
-        return self.text[self.begin:self.end]
-
-    def __getitem__(self, index):
-        # assert isinstance(index, slice), "As of now, StringView only allows slicing."
-        # assert index.step is None or index.step == 1, \
-        #     "Step sizes other than 1 are not yet supported by StringView"
-        start, stop = real_indices(index.start, index.stop, self.len)
-        return StringView(self.text, self.begin + start, self.begin + stop)
-
-    def __eq__(self, other):
-        return str(self) == str(other)  # PERFORMANCE WARNING: This creates copies of the strings
-
-    def count(self, sub, start=None, end=None) -> int:
-        if self.fullstring_flag: