Move Style and related stuff to a separate module astyle.py.

Add classes for wrapping output streams.

IPython/Extensions/astyle.py

@@ -0,0 +1,390 b''
+"""
+``astyle`` provides classes for adding style (foreground and background color;
+bold; blink; etc.) to terminal and curses output.
+"""
+
+
+import os
+
+try:
+    import curses
+except ImportError:
+    curses = None
+
+
+COLOR_BLACK   = 0
+COLOR_RED     = 1
+COLOR_GREEN   = 2
+COLOR_YELLOW  = 3
+COLOR_BLUE    = 4
+COLOR_MAGENTA = 5
+COLOR_CYAN    = 6
+COLOR_WHITE   = 7
+
+A_BLINK     = 1<<0 # Blinking text
+A_BOLD      = 1<<1 # Extra bright or bold text
+A_DIM       = 1<<2 # Half bright text
+A_REVERSE   = 1<<3 # Reverse-video text
+A_STANDOUT  = 1<<4 # The best highlighting mode available
+A_UNDERLINE = 1<<5 # Underlined text
+
+
+class Style(object):
+    """
+    Store foreground color, background color and attribute (bold, underlined
+    etc.).
+    """
+    __slots__ = ("fg", "bg", "attrs")
+
+    COLORNAMES = {
+        "black": COLOR_BLACK,
+        "red": COLOR_RED,
+        "green": COLOR_GREEN,
+        "yellow": COLOR_YELLOW,
+        "blue": COLOR_BLUE,
+        "magenta": COLOR_MAGENTA,
+        "cyan": COLOR_CYAN,
+        "white": COLOR_WHITE,
+    }
+    ATTRNAMES = {
+        "blink": A_BLINK,
+        "bold": A_BOLD,
+        "dim": A_DIM,
+        "reverse": A_REVERSE,
+        "standout": A_STANDOUT,
+        "underline": A_UNDERLINE,
+    }
+
+    def __init__(self, fg, bg, attrs=0):
+        """
+        Create a ``Style`` object with ``fg`` as the foreground color,
+        ``bg`` as the background color and ``attrs`` as the attributes.
+
+        Examples:
+
+            >>> Style(COLOR_RED, COLOR_BLACK)
+            >>> Style(COLOR_YELLOW, COLOR_BLUE, A_BOLD|A_UNDERLINE)
+        """
+        self.fg = fg
+        self.bg = bg
+        self.attrs = attrs
+
+    def __call__(self, *args):
+        text = Text()
+        for arg in args:
+            if isinstance(arg, Text):
+                text.extend(arg)
+            else:
+                text.append((self, arg))
+        return text
+
+    def __eq__(self, other):
+        return self.fg == other.fg and self.bg == other.bg and self.attrs == other.attrs
+
+    def __neq__(self, other):
+        return self.fg != other.fg or self.bg != other.bg or self.attrs != other.attrs
+
+    def __repr__(self):
+        color2name = ("black", "red", "green", "yellow", "blue", "magenta", "cyan", "white")
+        attrs2name = ("blink", "bold", "dim", "reverse", "standout", "underline")
+
+        return "<%s fg=%s bg=%s attrs=%s>" % (
+            self.__class__.__name__, color2name[self.fg], color2name[self.bg],
+            "|".join([attrs2name[b] for b in xrange(6) if self.attrs&(1<<b)]) or 0)
+
+    def fromstr(cls, value):
+        """
+        Create a ``Style`` object from a string. The format looks like this:
+        ``"red:black:bold|blink"``.
+        """
+        # defaults
+        fg = COLOR_WHITE
+        bg = COLOR_BLACK
+        attrs = 0
+
+        parts = value.split(":")
+        if len(parts) > 0:
+            fg = cls.COLORNAMES[parts[0].lower()]
+            if len(parts) > 1:
+                bg = cls.COLORNAMES[parts[1].lower()]
+                if len(parts) > 2:
+                    for strattr in parts[2].split("|"):
+                        attrs |= cls.ATTRNAMES[strattr.lower()]
+        return cls(fg, bg, attrs)
+    fromstr = classmethod(fromstr)
+
+    def fromenv(cls, name, default):
+        """
+        Create a ``Style`` from an environment variable named ``name``
+        (using ``default`` if the environment variable doesn't exist).
+        """
+        return cls.fromstr(os.environ.get(name, default))
+    fromenv = classmethod(fromenv)
+
+
+def switchstyle(s1, s2):
+    """
+    Return the ANSI escape sequence needed to switch from style ``s1`` to
+    style ``s2``.
+    """
+    attrmask = (A_BLINK|A_BOLD|A_UNDERLINE|A_REVERSE)
+    a1 = s1.attrs & attrmask
+    a2 = s2.attrs & attrmask
+
+    args = []
+    if s1 != s2:
+        # do we have to get rid of the bold/underline/blink bit?
+        # (can only be done by a reset)
+        # use reset when our target color is the default color
+        # (this is shorter than 37;40)
+        if (a1 & ~a2 or s2==style_default):
+            args.append("0")
+            s1 = style_default
+            a1 = 0
+
+        # now we know that old and new color have the same boldness,
+        # or the new color is bold and the old isn't,
+        # i.e. we only might have to switch bold on, not off
+        if not (a1 & A_BOLD) and (a2 & A_BOLD):
+            args.append("1")
+
+        # Fix underline
+        if not (a1 & A_UNDERLINE) and (a2 & A_UNDERLINE):
+            args.append("4")
+
+        # Fix blink
+        if not (a1 & A_BLINK) and (a2 & A_BLINK):
+            args.append("5")
+
+        # Fix reverse
+        if not (a1 & A_REVERSE) and (a2 & A_REVERSE):
+            args.append("7")
+
+        # Fix foreground color
+        if s1.fg != s2.fg:
+            args.append("3%d" % s2.fg)
+
+        # Finally fix the background color
+        if s1.bg != s2.bg:
+            args.append("4%d" % s2.bg)
+
+        if args:
+            return "\033[%sm" % ";".join(args)
+    return ""
+
+
+class Text(list):
+    """
+    A colored string. A ``Text`` object is a sequence, the sequence
+    items will be ``(style, string)`` tuples.
+    """
+
+    def __init__(self, *args):
+        list.__init__(self)
+        self.append(*args)
+
+    def __repr__(self):
+        return "%s.%s(%s)" % (
+            self.__class__.__module__, self.__class__.__name__,
+            list.__repr__(self)[1:-1])
+
+    def append(self, *args):
+        for arg in args:
+            if isinstance(arg, Text):
+                self.extend(arg)
+            elif isinstance(arg, tuple): # must be (style, string)
+                list.append(self, arg)
+            elif isinstance(arg, unicode):
+                list.append(self, (style_default, arg))
+            else:
+                list.append(self, (style_default, str(arg)))
+
+    def insert(self, index, *args):
+        self[index:index] = Text(*args)
+
+    def __add__(self, other):
+        new = Text()
+        new.append(self)
+        new.append(other)
+        return new
+
+    def __iadd__(self, other):
+        self.append(other)
+        return self
+
+    def format(self, styled=True):
+        """
+        This generator yields the strings that will make up the final
+        colorized string.
+        """
+        if styled:
+            oldstyle = style_default
+            for (style, string) in self:
+                if not isinstance(style, (int, long)):
+                    switch = switchstyle(oldstyle, style)
+                    if switch:
+                        yield switch
+                    if string:
+                        yield string
+                    oldstyle = style
+            switch = switchstyle(oldstyle, style_default)
+            if switch:
+                yield switch
+        else:
+            for (style, string) in self:
+                if not isinstance(style, (int, long)):
+                    yield string
+
+    def string(self, styled=True):
+        """
+        Return the resulting string (with escape sequences, if ``styled``
+        is true).
+        """
+        return "".join(self.format(styled))
+
+    def __str__(self):
+        """
+        Return ``self`` as a string (without ANSI escape sequences).
+        """
+        return self.string(False)
+
+    def write(self, stream, styled=True):
+        """
+        Write ``self`` to the output stream ``stream`` (with escape sequences,
+        if ``styled`` is true).
+        """
+        for part in self.format(styled):
+            stream.write(part)
+
+    def __xrepr__(self, mode="default"):
+        yield (-1, True)
+        for info in self:
+            yield info
+
+
+def streamstyle(stream, styled=None):
+    """
+    If ``styled`` is ``None``, return whether ``stream`` refers to a terminal.
+    If this can't be determined (either because ``stream`` doesn't refer to a
+    real OS file, or because you're on Windows) return ``False``. If ``styled``
+    is not ``None`` ``styled`` will be returned unchanged.
+    """
+    if styled is None:
+        try:
+            styled = os.isatty(stream.fileno())
+        except (KeyboardInterrupt, SystemExit):
+            raise
+        except Exception:
+            styled = False
+    return styled
+
+
+def write(stream, styled, *texts):
+    """
+    Write ``texts`` to ``stream``.
+    """
+    text = Text(*texts)
+    text.write(stream, streamstyle(stream, styled))
+
+
+def writeln(stream, styled, *texts):
+    """
+    Write ``texts`` to ``stream`` and finish with a line feed.
+    """
+    write(stream, styled, *texts)
+    stream.write("\n")
+
+
+class Stream(object):
+    """
+    Stream wrapper that adds color output.
+    """
+    def __init__(self, stream, styled=None):
+        self.stream = stream
+        self.styled = streamstyle(stream, styled)
+
+    def write(self, *texts):
+        write(self.stream, self.styled, *texts)
+
+    def writeln(self, *texts):
+        writeln(self.stream, self.styled, *texts)
+
+    def __getattr__(self, name):
+        return getattr(self.stream, name)
+
+
+class stdout(object):
+    """
+    Stream wrapper for ``sys.stdout`` that adds color output.
+    """
+    def write(self, *texts):
+        write(sys.stdout, None, *texts)
+
+    def writeln(self, *texts):
+        writeln(sys.stdout, None, *texts)
+
+    def __getattr__(self, name):
+        return getattr(sys.stdout, name)
+stdout = stdout()
+
+
+class stderr(object):
+    """
+    Stream wrapper for ``sys.stderr`` that adds color output.
+    """
+    def write(self, *texts):
+        write(sys.stderr, None, *texts)
+
+    def writeln(self, *texts):
+        writeln(sys.stderr, None, *texts)
+
+    def __getattr__(self, name):
+        return getattr(sys.stdout, name)
+stderr = stderr()
+
+
+if curses is not None:
+    # This is probably just range(8)
+    COLOR2CURSES = [
+        COLOR_BLACK,
+        COLOR_RED,
+        COLOR_GREEN,
+        COLOR_YELLOW,
+        COLOR_BLUE,
+        COLOR_MAGENTA,
+        COLOR_CYAN,
+        COLOR_WHITE,
+    ]
+
+    A2CURSES = {
+        A_BLINK: curses.A_BLINK,
+        A_BOLD: curses.A_BOLD,
+        A_DIM: curses.A_DIM,
+        A_REVERSE: curses.A_REVERSE,
+        A_STANDOUT: curses.A_STANDOUT,
+        A_UNDERLINE: curses.A_UNDERLINE,
+    }
+
+
+# default style
+style_default = Style.fromstr("white:black")
+
+# Styles for datatypes
+style_type_none = Style.fromstr("magenta:black")
+style_type_bool = Style.fromstr("magenta:black")
+style_type_number = Style.fromstr("yellow:black")
+style_type_datetime = Style.fromstr("magenta:black")
+
+# Style for URLs and file/directory names
+style_url = Style.fromstr("green:black")
+style_dir = Style.fromstr("cyan:black")
+style_file = Style.fromstr("green:black")
+
+# Style for ellipsis (when an output has been shortened
+style_ellisis = Style.fromstr("red:black")
+
+# Style for displaying exceptions
+style_error = Style.fromstr("red:black")
+
+# Style for displaying non-existing attributes
+style_nodata = Style.fromstr("red:black")