Allow background without foreground ("none.blue")

Use a configurable fore/background separator.
Declare fore- and background colors only once.
Pretty print context in debug mode.

colout/colout.py

@@ -18,6 +18,8 @@ import string
 import hashlib
 import functools
 import argparse
+import pprint
+import copy
 
 # set the SIGPIPE handler to kill the program instead of
 # ending in a write error when a broken pipe occurs
@@ -38,23 +40,21 @@ context["styles"] = {
     "reverse": 7, "conceal": 8
 }
 
-# Available color names in 8-colors mode
-context["colors"] = {
-    "black": 0, "red": 1, "green": 2, "yellow": 3, "orange":3, "blue": 4,
-    "magenta": 5, "purple": 5, "cyan": 6, "white": 7, "none": -1
-}
+# Available color names in 8-colors mode.
+eight_colors = ["black","red","green","yellow","blue","magenta","cyan","white"]
+# Given in that order, the ASCII code is the index.
+eight_color_codes = {n:i for i,n in enumerate(eight_colors)}
+# One can add synonyms.
+eight_color_codes["orange"] = eight_color_codes["yellow"]
+eight_color_codes["purple"] = eight_color_codes["magenta"]
 
+# Foreground colors has a special "none" item.
+# Note: use copy to avoid having the same reference over fore/background.
+context["colors"] = copy.copy(eight_color_codes)
+context["colors"]["none"] = -1
 
-context["backgrounds"] = {
-    "black": 0,
-    "red": 1,
-    "green": 2,
-    "yellow": 3,
-    "blue": 4,
-    "magenta": 5,
-    "cyan": 6,
-    "white": 7
-    }
+# Background has the same colors than foreground, but without the none code.
+context["backgrounds"] = copy.copy(eight_color_codes)
 
 context["themes"] = {}
 
@@ -90,6 +90,10 @@ context["scale"] = (0,100)
 
 context["lexers"] = []
 
+# Character use as a delimiter
+# between foreground and background.
+context["groundmark"]="."
+
 class UnknownColor(Exception):
     pass
 
@@ -492,10 +496,14 @@ def color_lexer( name, style, text ):
         return "<"+name+">"+ highlight(text, lexer, formatter)[:-1] + "</"+name+">"
 
 
-def colorin(text, color="red", style="normal"):
+def colorin(text, color="red", style="normal", groundmark=context["groundmark"]):
     """
     Return the given text, surrounded by the given color ASCII markers.
 
+    The given color may be either a single name, encoding the foreground color,
+    or a pair of names, delimited by the given groundmark,
+    encoding foreground and background, e.g. "red.blue".
+
     If the given color is a name that exists in available colors,
     a 8-colors mode is assumed, else, a 256-colors mode.
 
@@ -521,25 +529,25 @@ def colorin(text, color="red", style="normal"):
     color_code = ""
     style_code = ""
     background_code = ""
-    list_style_code = []
-    
+    style_codes = []
+
     # Convert the style code
     if style == "random" or style == "Random":
         style = random.choice(list(context["styles"].keys()))
     else:
-        styles = style.split(".")
+        styles = style.split(groundmark)
         for astyle in styles:
             if astyle in context["styles"]:
-                list_style_code.append(str(context["styles"][astyle]))
-        style_code = ";".join(list_style_code)
-        
-    color_background = color.strip().split(".")
-    color = color_background[0]
-    background = color_background[1] if len(color_background) == 2 else None
+                style_codes.append(str(context["styles"][astyle]))
+        style_code = ";".join(style_codes)
+
+    color_pair = color.strip().split(groundmark)
+    color = color_pair[0]
+    background = color_pair[1] if len(color_pair) == 2 else "none"
 
     m = mode(color)
 
-    if color == "none":
+    if color == "none" and background == "none":
         # if no color, style cannot be applied
         if not debug:
             return text
@@ -594,20 +602,24 @@ def colorin(text, color="red", style="normal"):
 
     if background in context["backgrounds"] and m == 8:
         background_code = endmarks[m] + str(40 + context["backgrounds"][background]) 
-    elif background == None:
+    elif background == "none":
         pass
     else:
         raise UnknownColor(background)
 
-    
     if color_code is not None:
         if not debug:
             return start + style_code + endmarks[m] + color_code + background_code + "m" + text + stop
         else:
-            return start + style_code + endmarks[m] + color_code + "m" \
-                    + "<color name=" + str(color) + " code=" + color_code \
-                    + " style=" + str(style) + " stylecode=" + style_code \
-                    + " mode=" + str(m) + ">" \
+            return start + style_code + endmarks[m] + color_code + background_code + "m" \
+                    + "<color name=" + str(color) \
+                    + " code=" + color_code \
+                    + " style=" + str(style) \
+                    + " stylecode=" + style_code \
+                    + " background=" + str(background) \
+                    + " backgroundcode=" + background_code.strip(endmarks[m]) \
+                    + " mode=" + str(m) \
+                    + ">" \
                     + text + "</color>" + stop
     else:
         if not debug:
@@ -726,8 +738,6 @@ def write(colored, stream = sys.stdout):
     """
     Write "colored" on sys.stdout, then flush.
     """
-    if isinstance(colored, unicode):
-        colored = colored.encode('utf-8')
     try:
         stream.write(colored)
         stream.flush()
@@ -912,6 +922,11 @@ if __name__ == "__main__":
     ##################
     # Load resources #
     ##################
+
+    if debug:
+        setting = pprint.pformat(context, depth=2)
+        logging.debug(setting)
+
     try:
         # Search for available resources files (themes, palettes)
         # in the same dir as the colout.py script