Source code for blessed.formatters

"""Sub-module providing sequence-formatting functions."""
# std imports
import platform

# 3rd party
import six

# local
from blessed.colorspace import CGA_COLORS, X11_COLORNAMES_TO_RGB

# curses
if platform.system() == 'Windows':
    import jinxed as curses   # pylint: disable=import-error
else:
    import curses


[docs]def _make_colors(): """ Return set of valid colors and their derivatives. :rtype: set :returns: Color names with prefixes """ colors = set() # basic CGA foreground color, background, high intensity, and bold # background ('iCE colors' in my day). for cga_color in CGA_COLORS: colors.add(cga_color) colors.add('on_' + cga_color) colors.add('bright_' + cga_color) colors.add('on_bright_' + cga_color) # foreground and background VGA color for vga_color in X11_COLORNAMES_TO_RGB: colors.add(vga_color) colors.add('on_' + vga_color) return colors
#: Valid colors and their background (on), bright, and bright-background #: derivatives. COLORS = _make_colors() #: Attributes that may be compounded with colors, by underscore, such as #: 'reverse_indigo'. COMPOUNDABLES = set('bold underline reverse blink italic standout'.split())
[docs]class ParameterizingString(six.text_type): r""" A Unicode string which can be called as a parameterizing termcap. For example:: >>> from blessed import Terminal >>> term = Terminal() >>> color = ParameterizingString(term.color, term.normal, 'color') >>> color(9)('color #9') u'\x1b[91mcolor #9\x1b(B\x1b[m' """ def __new__(cls, cap, normal=u'', name=u'<not specified>'): # pylint: disable = missing-return-doc, missing-return-type-doc """ Class constructor accepting 3 positional arguments. :arg str cap: parameterized string suitable for curses.tparm() :arg str normal: terminating sequence for this capability (optional). :arg str name: name of this terminal capability (optional). """ new = six.text_type.__new__(cls, cap) new._normal = normal new._name = name return new
[docs] def __call__(self, *args): """ Returning :class:`FormattingString` instance for given parameters. Return evaluated terminal capability (self), receiving arguments ``*args``, followed by the terminating sequence (self.normal) into a :class:`FormattingString` capable of being called. :raises TypeError: Mismatch between capability and arguments :raises curses.error: :func:`curses.tparm` raised an exception :rtype: :class:`FormattingString` or :class:`NullCallableString` :returns: Callable string for given parameters """ try: # Re-encode the cap, because tparm() takes a bytestring in Python # 3. However, appear to be a plain Unicode string otherwise so # concats work. attr = curses.tparm(self.encode('latin1'), *args).decode('latin1') return FormattingString(attr, self._normal) except TypeError as err: # If the first non-int (i.e. incorrect) arg was a string, suggest # something intelligent: if args and isinstance(args[0], six.string_types): raise TypeError( "Unknown terminal capability, %r, or, TypeError " "for arguments %r: %s" % (self._name, args, err)) # Somebody passed a non-string; I don't feel confident # guessing what they were trying to do. raise except curses.error as err: # ignore 'tparm() returned NULL', you won't get any styling, # even if does_styling is True. This happens on win32 platforms # with http://www.lfd.uci.edu/~gohlke/pythonlibs/#curses installed if "tparm() returned NULL" not in six.text_type(err): raise return NullCallableString()
[docs]class ParameterizingProxyString(six.text_type): r""" A Unicode string which can be called to proxy missing termcap entries. This class supports the function :func:`get_proxy_string`, and mirrors the behavior of :class:`ParameterizingString`, except that instead of a capability name, receives a format string, and callable to filter the given positional ``*args`` of :meth:`ParameterizingProxyString.__call__` into a terminal sequence. For example:: >>> from blessed import Terminal >>> term = Terminal('screen') >>> hpa = ParameterizingString(term.hpa, term.normal, 'hpa') >>> hpa(9) u'' >>> fmt = u'\x1b[{0}G' >>> fmt_arg = lambda *arg: (arg[0] + 1,) >>> hpa = ParameterizingProxyString((fmt, fmt_arg), term.normal, 'hpa') >>> hpa(9) u'\x1b[10G' """ def __new__(cls, fmt_pair, normal=u'', name=u'<not specified>'): # pylint: disable = missing-return-doc, missing-return-type-doc """ Class constructor accepting 4 positional arguments. :arg tuple fmt_pair: Two element tuple containing: - format string suitable for displaying terminal sequences - callable suitable for receiving __call__ arguments for formatting string :arg str normal: terminating sequence for this capability (optional). :arg str name: name of this terminal capability (optional). """ assert isinstance(fmt_pair, tuple), fmt_pair assert callable(fmt_pair[1]), fmt_pair[1] new = six.text_type.__new__(cls, fmt_pair[0]) new._fmt_args = fmt_pair[1] new._normal = normal new._name = name return new
[docs] def __call__(self, *args): """ Returning :class:`FormattingString` instance for given parameters. Arguments are determined by the capability. For example, ``hpa`` (move_x) receives only a single integer, whereas ``cup`` (move) receives two integers. See documentation in terminfo(5) for the given capability. :rtype: FormattingString :returns: Callable string for given parameters """ return FormattingString(self.format(*self._fmt_args(*args)), self._normal)
[docs]class FormattingString(six.text_type): r""" A Unicode string which doubles as a callable. This is used for terminal attributes, so that it may be used both directly, or as a callable. When used directly, it simply emits the given terminal sequence. When used as a callable, it wraps the given (string) argument with the 2nd argument used by the class constructor:: >>> from blessed import Terminal >>> term = Terminal() >>> style = FormattingString(term.bright_blue, term.normal) >>> print(repr(style)) u'\x1b[94m' >>> style('Big Blue') u'\x1b[94mBig Blue\x1b(B\x1b[m' """ def __new__(cls, sequence, normal=u''): # pylint: disable = missing-return-doc, missing-return-type-doc """ Class constructor accepting 2 positional arguments. :arg str sequence: terminal attribute sequence. :arg str normal: terminating sequence for this attribute (optional). """ new = six.text_type.__new__(cls, sequence) new._normal = normal return new
[docs] def __call__(self, *args): """ Return ``text`` joined by ``sequence`` and ``normal``. :raises TypeError: Not a string type :rtype: str :returns: Arguments wrapped in sequence and normal """ # Jim Allman brings us this convenience of allowing existing # unicode strings to be joined as a call parameter to a formatting # string result, allowing nestation: # # >>> t.red('This is ', t.bold('extremely'), ' dangerous!') for idx, ucs_part in enumerate(args): if not isinstance(ucs_part, six.string_types): expected_types = ', '.join([ _type.__name__ for _type in six.string_types]) raise TypeError( "TypeError for FormattingString argument, " "%r, at position %s: expected type %s, " "got %s" % (ucs_part, idx, expected_types, type(ucs_part).__name__)) postfix = u'' if self and self._normal: postfix = self._normal _refresh = self._normal + self args = [_refresh.join(ucs_part.split(self._normal)) for ucs_part in args] return self + u''.join(args) + postfix
[docs]class FormattingOtherString(six.text_type): r""" A Unicode string which doubles as a callable for another sequence when called. This is used for the :meth:`~.Terminal.move_up`, ``down``, ``left``, and ``right()`` family of functions:: >>> from blessed import Terminal >>> term = Terminal() >>> move_right = FormattingOtherString(term.cuf1, term.cuf) >>> print(repr(move_right)) u'\x1b[C' >>> print(repr(move_right(666))) u'\x1b[666C' >>> print(repr(move_right())) u'\x1b[C' """ def __new__(cls, direct, target): # pylint: disable = missing-return-doc, missing-return-type-doc """ Class constructor accepting 2 positional arguments. :arg str direct: capability name for direct formatting, eg ``('x' + term.right)``. :arg str target: capability name for callable, eg ``('x' + term.right(99))``. """ new = six.text_type.__new__(cls, direct) new._callable = target return new def __getnewargs__(self): # return arguments used for the __new__ method upon unpickling. return six.text_type.__new__(six.text_type, self), self._callable
[docs] def __call__(self, *args): """Return ``text`` by ``target``.""" if args: return self._callable(*args) return self
[docs]class NullCallableString(six.text_type): """ A dummy callable Unicode alternative to :class:`FormattingString`. This is used for colors on terminals that do not support colors, it is just a basic form of unicode that may also act as a callable. """ def __new__(cls): """Class constructor.""" new = six.text_type.__new__(cls, u'') return new
[docs] def __call__(self, *args): """ Allow empty string to be callable, returning given string, if any. When called with an int as the first arg, return an empty Unicode. An int is a good hint that I am a :class:`ParameterizingString`, as there are only about half a dozen string-returning capabilities listed in terminfo(5) which accept non-int arguments, they are seldom used. When called with a non-int as the first arg (no no args at all), return the first arg, acting in place of :class:`FormattingString` without any attributes. """ if not args or isinstance(args[0], int): # As a NullCallableString, even when provided with a parameter, # such as t.color(5), we must also still be callable, fe: # # >>> t.color(5)('shmoo') # # is actually simplified result of NullCallable()() on terminals # without color support, so turtles all the way down: we return # another instance. return NullCallableString() return u''.join(args)
[docs]def get_proxy_string(term, attr): """ Proxy and return callable string for proxied attributes. :arg Terminal term: :class:`~.Terminal` instance. :arg str attr: terminal capability name that may be proxied. :rtype: None or :class:`ParameterizingProxyString`. :returns: :class:`ParameterizingProxyString` for some attributes of some terminal types that support it, where the terminfo(5) database would otherwise come up empty, such as ``move_x`` attribute for ``term.kind`` of ``screen``. Otherwise, None. """ # normalize 'screen-256color', or 'ansi.sys' to its basic names term_kind = next(iter(_kind for _kind in ('screen', 'ansi',) if term.kind.startswith(_kind)), term) _proxy_table = { # pragma: no cover 'screen': { # proxy move_x/move_y for 'screen' terminal type, used by tmux(1). 'hpa': ParameterizingProxyString( (u'\x1b[{0}G', lambda *arg: (arg[0] + 1,)), term.normal, attr), 'vpa': ParameterizingProxyString( (u'\x1b[{0}d', lambda *arg: (arg[0] + 1,)), term.normal, attr), }, 'ansi': { # proxy show/hide cursor for 'ansi' terminal type. There is some # demand for a richly working ANSI terminal type for some reason. 'civis': ParameterizingProxyString( (u'\x1b[?25l', lambda *arg: ()), term.normal, attr), 'cnorm': ParameterizingProxyString( (u'\x1b[?25h', lambda *arg: ()), term.normal, attr), 'hpa': ParameterizingProxyString( (u'\x1b[{0}G', lambda *arg: (arg[0] + 1,)), term.normal, attr), 'vpa': ParameterizingProxyString( (u'\x1b[{0}d', lambda *arg: (arg[0] + 1,)), term.normal, attr), 'sc': '\x1b[s', 'rc': '\x1b[u', } } return _proxy_table.get(term_kind, {}).get(attr, None)
[docs]def split_compound(compound): """ Split compound formating string into segments. >>> split_compound('bold_underline_bright_blue_on_red') ['bold', 'underline', 'bright_blue', 'on_red'] :arg str compound: a string that may contain compounds, separated by underline (``_``). :rtype: list :returns: List of formating string segments """ merged_segs = [] # These occur only as prefixes, so they can always be merged: mergeable_prefixes = ['on', 'bright', 'on_bright'] for segment in compound.split('_'): if merged_segs and merged_segs[-1] in mergeable_prefixes: merged_segs[-1] += '_' + segment else: merged_segs.append(segment) return merged_segs
[docs]def resolve_capability(term, attr): """ Resolve a raw terminal capability using :func:`tigetstr`. :arg Terminal term: :class:`~.Terminal` instance. :arg str attr: terminal capability name. :returns: string of the given terminal capability named by ``attr``, which may be empty (u'') if not found or not supported by the given :attr:`~.Terminal.kind`. :rtype: str """ if not term.does_styling: return u'' val = curses.tigetstr(term._sugar.get(attr, attr)) # pylint: disable=protected-access # Decode sequences as latin1, as they are always 8-bit bytes, so when # b'\xff' is returned, this is decoded as u'\xff'. return u'' if val is None else val.decode('latin1')
[docs]def resolve_color(term, color): """ Resolve a simple color name to a callable capability. This function supports :func:`resolve_attribute`. :arg Terminal term: :class:`~.Terminal` instance. :arg str color: any string found in set :const:`COLORS`. :returns: a string class instance which emits the terminal sequence for the given color, and may be used as a callable to wrap the given string with such sequence. :returns: :class:`NullCallableString` when :attr:`~.Terminal.number_of_colors` is 0, otherwise :class:`FormattingString`. :rtype: :class:`NullCallableString` or :class:`FormattingString` """ # pylint: disable=protected-access if term.number_of_colors == 0: return NullCallableString() # fg/bg capabilities terminals that support 0-256+ colors. vga_color_cap = (term._background_color if 'on_' in color else term._foreground_color) base_color = color.rsplit('_', 1)[-1] if base_color in CGA_COLORS: # curses constants go up to only 7, so add an offset to get at the # bright colors at 8-15: offset = 8 if 'bright_' in color else 0 base_color = color.rsplit('_', 1)[-1] attr = 'COLOR_%s' % (base_color.upper(),) fmt_attr = vga_color_cap(getattr(curses, attr) + offset) return FormattingString(fmt_attr, term.normal) assert base_color in X11_COLORNAMES_TO_RGB, ( 'color not known', base_color) rgb = X11_COLORNAMES_TO_RGB[base_color] # downconvert X11 colors to CGA, EGA, or VGA color spaces if term.number_of_colors <= 256: fmt_attr = vga_color_cap(term.rgb_downconvert(*rgb)) return FormattingString(fmt_attr, term.normal) # Modern 24-bit color terminals are written pretty basically. The # foreground and background sequences are: # - ^[38;2;<r>;<g>;<b>m # - ^[48;2;<r>;<g>;<b>m fgbg_seq = ('48' if 'on_' in color else '38') assert term.number_of_colors == 1 << 24 fmt_attr = u'\x1b[' + fgbg_seq + ';2;{0};{1};{2}m' return FormattingString(fmt_attr.format(*rgb), term.normal)
[docs]def resolve_attribute(term, attr): """ Resolve a terminal attribute name into a capability class. :arg Terminal term: :class:`~.Terminal` instance. :arg str attr: Sugary, ordinary, or compound formatted terminal capability, such as "red_on_white", "normal", "red", or "bold_on_black". :returns: a string class instance which emits the terminal sequence for the given terminal capability, or may be used as a callable to wrap the given string with such sequence. :returns: :class:`NullCallableString` when :attr:`~.Terminal.number_of_colors` is 0, otherwise :class:`FormattingString`. :rtype: :class:`NullCallableString` or :class:`FormattingString` """ if attr in COLORS: return resolve_color(term, attr) # A direct compoundable, such as `bold' or `on_red'. if attr in COMPOUNDABLES: sequence = resolve_capability(term, attr) return FormattingString(sequence, term.normal) # Given `bold_on_red', resolve to ('bold', 'on_red'), RECURSIVE # call for each compounding section, joined and returned as # a completed completed FormattingString. formatters = split_compound(attr) if all((fmt in COLORS or fmt in COMPOUNDABLES) for fmt in formatters): resolution = (resolve_attribute(term, fmt) for fmt in formatters) return FormattingString(u''.join(resolution), term.normal) # otherwise, this is our end-game: given a sequence such as 'csr' # (change scrolling region), return a ParameterizingString instance, # that when called, performs and returns the final string after curses # capability lookup is performed. tparm_capseq = resolve_capability(term, attr) if not tparm_capseq: # and, for special terminals, such as 'screen', provide a Proxy # ParameterizingString for attributes they do not claim to support, # but actually do! (such as 'hpa' and 'vpa'). proxy = get_proxy_string(term, term._sugar.get(attr, attr)) # pylint: disable=protected-access if proxy is not None: return proxy return ParameterizingString(tparm_capseq, term.normal, attr)