build_echon_expr() - Code Metrics - lambdalisue/neovim-prompt - Measure and Improve Code Quality continuously with Scrutinizer

build_echon_expr() B
last analyzed 2018-06-25 15:30 UTC

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cc	5
c	1
b	0
f	0
dl	0
loc	23
rs	8.8613

"""Utility module."""
import re
from collections import namedtuple
from typing import Dict  # noqa: F401

ESCAPE_ECHO = str.maketrans({
    '"': '\\"',
    '\\': '\\\\',
})

IMPRINTABLE_REPRESENTS = {
    '\a': '^G',
    '\b': '^H',             # NOTE: Neovim: <BS>, Vim: ^H. Follow Vim.
    '\t': '^I',
    '\n': '^J',
    '\v': '^K',
    '\f': '^L',
    '\r': '^M',
    '\udc80\udcffX': '^@',  # NOTE: ^0 representation in Vim.
}

IMPRINTABLE_PATTERN = re.compile(r'(%s)' % '|'.join(
    IMPRINTABLE_REPRESENTS.keys()
))

PatternSet = namedtuple('PatternSet', [
    'pattern',
    'inverse',
])

_cached_encoding = None

_cached_keyword_pattern_set = {}  # type: Dict[str, PatternSet]


def get_encoding(nvim):
    """Return a Vim's internal encoding.

    The retrieve encoding is cached to the function instance while encoding
    options should not be changed in Vim's live session (see :h encoding) to
    enhance performance.

    Args:
        nvim (neovim.Nvim): A ``neovim.Nvim`` instance.

    Returns:
        str: A Vim's internal encoding.
    """
    global _cached_encoding
    if _cached_encoding is None:
        _cached_encoding = nvim.options['encoding']
    return _cached_encoding


def ensure_bytes(nvim, seed):
    """Encode `str` to `bytes` if necessary and return.

    Args:
        nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
        seed (AnyStr): A str or bytes instance.

    Example:
        >>> from unittest.mock import MagicMock
        >>> nvim = MagicMock()
        >>> nvim.options = {'encoding': 'utf-8'}
        >>> ensure_bytes(nvim, b'a')
        b'a'
        >>> ensure_bytes(nvim, 'a')
        b'a'

    Returns:
        bytes: A bytes represantation of ``seed``.
    """
    if isinstance(seed, str):
        encoding = get_encoding(nvim)
        return seed.encode(encoding, 'surrogateescape')
    return seed


def ensure_str(nvim, seed):
    """Decode `bytes` to `str` if necessary and return.

    Args:
        nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
        seed (AnyStr): A str or bytes instance.

    Example:
        >>> from unittest.mock import MagicMock
        >>> nvim = MagicMock()
        >>> nvim.options = {'encoding': 'utf-8'}
        >>> ensure_str(nvim, b'a')
        'a'
        >>> ensure_str(nvim, 'a')
        'a'

    Returns:
        str: A str represantation of ``seed``.
    """
    if isinstance(seed, bytes):
        encoding = get_encoding(nvim)
        return seed.decode(encoding, 'surrogateescape')
    return seed


def int2char(nvim, code):
    """Return a corresponding char of `code`.

    It uses "nr2char()" in Vim script when 'encoding' option is not utf-8.
    Otherwise it uses "chr()" in Python to improve the performance.

    Args:
        nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
        code (int): A int which represent a single character.

    Example:
        >>> from unittest.mock import MagicMock
        >>> nvim = MagicMock()
        >>> nvim.options = {'encoding': 'utf-8'}
        >>> int2char(nvim, 97)
        'a'

    Returns:
        str: A str of ``code``.
    """
    encoding = get_encoding(nvim)
    if encoding in ('utf-8', 'utf8'):
        return chr(code)
    return nvim.call('nr2char', code)


def int2repr(nvim, code):
    """Return a string representation of a key with specified key code."""
    from .key import Key
    if isinstance(code, int):
        return int2char(nvim, code)
    return Key.represent(nvim, ensure_bytes(nvim, code))


def getchar(nvim, *args):
    """Call getchar and return int or bytes instance.

    Args:
        nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
        *args: Arguments passed to getchar function in Vim.

    Returns:
        Union[int, bytes]: A int or bytes.
    """
    try:
        ret = nvim.call('getchar', *args)
        if isinstance(ret, int):
            if ret == 0x03:
                # NOTE
                # Vim/Neovim usually raise an exception when user hit Ctrl-C
                # but sometime returns 0x03 (^C) instead.
                # While user might override <Esc> or <CR> and accidentaly
                # disable the way to exit neovim-prompt, Ctrl-C should be a
                # final way to exit the prompt. So raise KeyboardInterrupt
                # exception when 'ret' is 0x03 instead of returning 0x03.
                raise KeyboardInterrupt
            return ret
        return ensure_bytes(nvim, ret)
    except nvim.error as e:
        # NOTE:
        # neovim raise nvim.error instead of KeyboardInterrupt when Ctrl-C has
        # pressed so convert it to a real KeyboardInterrupt exception.
        if str(e) == "b'Keyboard interrupt'":
            raise KeyboardInterrupt
        raise e


def build_echon_expr(text, hl='None'):
    """Build 'echon' expression.

    Imprintable characters (e.g. '^M') are replaced to a corresponding
    representations used in Vim's command-line interface.

    Args:
        text (str): A text to be echon.
        hl (str): A highline name. Default is 'None'.

    Return:
        str: A Vim's command expression for 'echon'.
    """
    if not IMPRINTABLE_PATTERN.search(text):
        return 'echohl %s|echon "%s"' % (
            hl, text.translate(ESCAPE_ECHO)
        )
    p = 'echohl %s|echon "%%s"' % hl
    i = 'echohl %s|echon "%%s"' % ('SpecialKey' if hl == 'None' else hl)
    return '|'.join(
        p % term.translate(ESCAPE_ECHO)
        if index % 2 == 0 else i % IMPRINTABLE_REPRESENTS[term]
        for index, term in enumerate(IMPRINTABLE_PATTERN.split(text))
    )


def build_keyword_pattern_set(nvim):
    """Build a keyword pattern set from current 'iskeyword'.

    The result is cached by the value of 'iskeyword'.

    Args:
        nvim (neovim.Nvim): A ``neovim.Nvim`` instance.

    Returns:
        PatternSet
    """
    # NOTE:
    # iskeyword is similar to isfname and in Vim's help, isfname always
    # include multi-byte characters so only ASCII characters need to be
    # considered
    #
    # > Multi-byte characters 256 and above are always included, only the
    # > characters up to 255 are specified with this option.
    iskeyword = nvim.current.buffer.options['iskeyword']
    if iskeyword not in _cached_keyword_pattern_set:
        source = frozenset(chr(c) for c in range(0x20, 0xff))
        non_keyword_set = frozenset(nvim.call(
            'substitute',
            ''.join(source),
            r'\k\+',
            '', 'g'
        ))
        keyword_set = source - non_keyword_set
        # Convert frozenset to str and remove whitespaces
        keyword = re.sub(r'\s+', '', ''.join(keyword_set))
        non_keyword = re.sub(r'\s+', '', ''.join(non_keyword_set))
        _cached_keyword_pattern_set[iskeyword] = PatternSet(
            pattern=r'[%s]' % re.escape(keyword),
            inverse=r'[%s]' % re.escape(non_keyword),
        )
    return _cached_keyword_pattern_set[iskeyword]


# http://python-3-patterns-idioms-test.readthedocs.io/en/latest/Metaprogramming.html
class Singleton(type):
    """A singleton metaclass."""

    instance = None

    def __call__(cls, *args, **kwargs):  # noqa
        if not cls.instance:
            cls.instance = super().__call__(*args, **kwargs)
        return cls.instance


1			"""Utility module."""
2			import re
3			from collections import namedtuple
4			from typing import Dict # noqa: F401
5
6			ESCAPE_ECHO = str.maketrans({
7			'"': '\\"',
8			'\\': '\\\\',
9			})
10
11			IMPRINTABLE_REPRESENTS = {
12			'\a': '^G',
13			'\b': '^H', # NOTE: Neovim: <BS>, Vim: ^H. Follow Vim.
14			'\t': '^I',
15			'\n': '^J',
16			'\v': '^K',
17			'\f': '^L',
18			'\r': '^M',
19			'\udc80\udcffX': '^@', # NOTE: ^0 representation in Vim.
20			}
21
22			IMPRINTABLE_PATTERN = re.compile(r'(%s)' % '\|'.join(
23			IMPRINTABLE_REPRESENTS.keys()
24			))
25
26			PatternSet = namedtuple('PatternSet', [
27			'pattern',
28			'inverse',
29			])
30
31			_cached_encoding = None
32
33			_cached_keyword_pattern_set = {} # type: Dict[str, PatternSet]
34
35
36			def get_encoding(nvim):
37			"""Return a Vim's internal encoding.
38
39			The retrieve encoding is cached to the function instance while encoding
40			options should not be changed in Vim's live session (see :h encoding) to
41			enhance performance.
42
43			Args:
44			nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
45
46			Returns:
47			str: A Vim's internal encoding.
48			"""
49			global _cached_encoding
50			if _cached_encoding is None:
51			_cached_encoding = nvim.options['encoding']
52			return _cached_encoding
53
54
55			def ensure_bytes(nvim, seed):
56			"""Encode `str` to `bytes` if necessary and return.
57
58			Args:
59			nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
60			seed (AnyStr): A str or bytes instance.
61
62			Example:
63			>>> from unittest.mock import MagicMock
64			>>> nvim = MagicMock()
65			>>> nvim.options = {'encoding': 'utf-8'}
66			>>> ensure_bytes(nvim, b'a')
67			b'a'
68			>>> ensure_bytes(nvim, 'a')
69			b'a'
70
71			Returns:
72			bytes: A bytes represantation of ``seed``.
73			"""
74			if isinstance(seed, str):
75			encoding = get_encoding(nvim)
76			return seed.encode(encoding, 'surrogateescape')
77			return seed
78
79
80			def ensure_str(nvim, seed):
81			"""Decode `bytes` to `str` if necessary and return.
82
83			Args:
84			nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
85			seed (AnyStr): A str or bytes instance.
86
87			Example:
88			>>> from unittest.mock import MagicMock
89			>>> nvim = MagicMock()
90			>>> nvim.options = {'encoding': 'utf-8'}
91			>>> ensure_str(nvim, b'a')
92			'a'
93			>>> ensure_str(nvim, 'a')
94			'a'
95
96			Returns:
97			str: A str represantation of ``seed``.
98			"""
99			if isinstance(seed, bytes):
100			encoding = get_encoding(nvim)
101			return seed.decode(encoding, 'surrogateescape')
102			return seed
103
104
105			def int2char(nvim, code):
106			"""Return a corresponding char of `code`.
107
108			It uses "nr2char()" in Vim script when 'encoding' option is not utf-8.
109			Otherwise it uses "chr()" in Python to improve the performance.
110
111			Args:
112			nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
113			code (int): A int which represent a single character.
114
115			Example:
116			>>> from unittest.mock import MagicMock
117			>>> nvim = MagicMock()
118			>>> nvim.options = {'encoding': 'utf-8'}
119			>>> int2char(nvim, 97)
120			'a'
121
122			Returns:
123			str: A str of ``code``.
124			"""
125			encoding = get_encoding(nvim)
126			if encoding in ('utf-8', 'utf8'):
127			return chr(code)
128			return nvim.call('nr2char', code)
129
130
131			def int2repr(nvim, code):
132			"""Return a string representation of a key with specified key code."""
133			from .key import Key
134			if isinstance(code, int):
135			return int2char(nvim, code)
136			return Key.represent(nvim, ensure_bytes(nvim, code))
137
138
139			def getchar(nvim, *args):
140			"""Call getchar and return int or bytes instance.
141
142			Args:
143			nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
144			*args: Arguments passed to getchar function in Vim.
145
146			Returns:
147			Union[int, bytes]: A int or bytes.
148			"""
149			try:
150			ret = nvim.call('getchar', *args)
151			if isinstance(ret, int):
152			if ret == 0x03:
153			# NOTE
154			# Vim/Neovim usually raise an exception when user hit Ctrl-C
155			# but sometime returns 0x03 (^C) instead.
156			# While user might override <Esc> or <CR> and accidentaly
157			# disable the way to exit neovim-prompt, Ctrl-C should be a
158			# final way to exit the prompt. So raise KeyboardInterrupt
159			# exception when 'ret' is 0x03 instead of returning 0x03.
160			raise KeyboardInterrupt
161			return ret
162			return ensure_bytes(nvim, ret)
163			except nvim.error as e:
164			# NOTE:
165			# neovim raise nvim.error instead of KeyboardInterrupt when Ctrl-C has
166			# pressed so convert it to a real KeyboardInterrupt exception.
167			if str(e) == "b'Keyboard interrupt'":
168			raise KeyboardInterrupt
169			raise e
170
171
172			def build_echon_expr(text, hl='None'):
173			"""Build 'echon' expression.
174
175			Imprintable characters (e.g. '^M') are replaced to a corresponding
176			representations used in Vim's command-line interface.
177
178			Args:
179			text (str): A text to be echon.
180			hl (str): A highline name. Default is 'None'.
181
182			Return:
183			str: A Vim's command expression for 'echon'.
184			"""
185			if not IMPRINTABLE_PATTERN.search(text):
186			return 'echohl %s\|echon "%s"' % (
187			hl, text.translate(ESCAPE_ECHO)
188			)
189			p = 'echohl %s\|echon "%%s"' % hl
190			i = 'echohl %s\|echon "%%s"' % ('SpecialKey' if hl == 'None' else hl)
191			return '\|'.join(
192			p % term.translate(ESCAPE_ECHO)
193			if index % 2 == 0 else i % IMPRINTABLE_REPRESENTS[term]
194			for index, term in enumerate(IMPRINTABLE_PATTERN.split(text))
195			)
196
197
198			def build_keyword_pattern_set(nvim):
199			"""Build a keyword pattern set from current 'iskeyword'.
200
201			The result is cached by the value of 'iskeyword'.
202
203			Args:
204			nvim (neovim.Nvim): A ``neovim.Nvim`` instance.
205
206			Returns:
207			PatternSet
208			"""
209			# NOTE:
210			# iskeyword is similar to isfname and in Vim's help, isfname always
211			# include multi-byte characters so only ASCII characters need to be
212			# considered
213			#
214			# > Multi-byte characters 256 and above are always included, only the
215			# > characters up to 255 are specified with this option.
216			iskeyword = nvim.current.buffer.options['iskeyword']
217			if iskeyword not in _cached_keyword_pattern_set:
218			source = frozenset(chr(c) for c in range(0x20, 0xff))
219			non_keyword_set = frozenset(nvim.call(
220			'substitute',
221			''.join(source),
222			r'\k\+',
223			'', 'g'
224			))
225			keyword_set = source - non_keyword_set
226			# Convert frozenset to str and remove whitespaces
227			keyword = re.sub(r'\s+', '', ''.join(keyword_set))
228			non_keyword = re.sub(r'\s+', '', ''.join(non_keyword_set))
229			_cached_keyword_pattern_set[iskeyword] = PatternSet(
230			pattern=r'[%s]' % re.escape(keyword),
231			inverse=r'[%s]' % re.escape(non_keyword),
232			)
233			return _cached_keyword_pattern_set[iskeyword]
234
235
236			# http://python-3-patterns-idioms-test.readthedocs.io/en/latest/Metaprogramming.html
237			class Singleton(type):
238			"""A singleton metaclass."""
239
240			instance = None
241
242			def __call__(cls, args, *kwargs): # noqa
243			if not cls.instance:
244			cls.instance = super().__call__(args, *kwargs)
245			return cls.instance
246

lambdalisue / neovim-prompt

build_echon_expr() B last analyzed 2018-06-25 15:30 UTC

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build_echon_expr() B
last analyzed 2018-06-25 15:30 UTC