Colourised error output

docs/jottings.txt

@@ -540,3 +540,21 @@ dictionaries and so on into the main domain. We can then discard the old
 Builder, since they're no longer of any interest.
 
 .. vim: set filetype=rst tabstop=8 softtabstop=2 shiftwidth=2 expandtab:
+
+Colourised output
+=================
+
+Since gcc tends to output in colour these days, wouldn't it would be nice
+if you could get the same colour coding from muddle when things go wrong?
+Well now you can, and it's enabled by default. To make it work, all you
+need to do is ``apt install python-colorama`` or ``pip install colorama``.
+
+Colourisation is controlled by the ``MUDDLE_COLOURISE`` environment
+variable. The known values are:
+
+* ``auto`` (default): Detect whether muddle is running in a tty and colourise
+if so.
+* ``yes``: Always colourise
+* ``no``: Never colourise
+* ``html``: Always colourise for HTML. This is for use with Continuous
+Integration systems.

muddled/colourize.py

@@ -0,0 +1,143 @@
+# -*- coding: utf-8 -*-
+"""
+Output colourisation
+Inspired by colorgcc, this makes long gcc output easier on the eye.
+(Why yes, I do know about gcc 4.9's ability to colour to the terminal.  But in
+this muddled world, gcc is not outputting to a tty, so doesn't colourise.  To
+force it, you'd have to set a cflag in every last package, so it's much better
+to do this centrally. Doing it this way also picks up gcc-like errors from
+other tools.)
+"""
+
+import os
+import re
+import sys
+from collections import defaultdict,Container
+
+# Requires colorama to be able to colour, but won't fall over if it's not there.
+# - 'apt install python-colorama' or 'pip install colorama'
+try:
+    from colorama import Fore, Back, Style
+
+    colour = {
+        # These are all the styles we might set
+        'reset': Style.RESET_ALL,
+        'filename': Fore.WHITE + Style.BRIGHT,
+        'line_num': Fore.WHITE + Style.BRIGHT,
+        'line_pos': Fore.WHITE + Style.BRIGHT,
+        'quoted': Fore.WHITE + Style.BRIGHT,
+
+        'error': Fore.RED + Style.BRIGHT,
+        'warning': Fore.MAGENTA + Style.BRIGHT,
+        'note': Fore.CYAN,
+        'intro': Fore.CYAN,
+        'introquote': Fore.CYAN,
+        }
+    have_colour = True
+except ImportError:
+    # Quietly fall back to uncoloured behaviour
+    colour = defaultdict(lambda:'')
+    have_colour = False
+
+if os.getenv('MUDDLE_COLOURISE') == 'html':
+    # Alternate mode for HTML output.. wrap text up in CSS classes
+    class htmlcolour(Container):
+        def __getitem__(self, key):
+            if key=='reset':
+                return '</span>'
+            return '<span class="%s">'%key
+        def __contains__(self):
+            return True
+    colour = htmlcolour()
+    have_colour = True
+
+def wrap_colour(string, col):
+    ''' Colourises a string '''
+    return colour[col] + string + colour['reset']
+
+def colour_quote(string, inside):
+    ''' colourises things found between quotes and smart quotes
+        @inside@ is a member of the colour dict, it is applied to whatever is found inside quotes
+    '''
+    # blah blah `thing to highlight' blah
+    string = re.sub(r'`([^\']+)\'', '`' + colour[inside] + r'\1' + colour['reset'] + "'", string)
+    # blah blah ‘smart quoted thing’ blah
+    string = re.sub(r'‘([^’]+)’', '‘' + colour[inside] + r'\1' + colour['reset'] + '’', string)
+    # sometimes gcc doesn't even bother with the backquote when muddle is capturing the output?
+    string = re.sub(r'\'([^\']+)\'', '\'' + colour[inside] + r'\1' + colour['reset'] + "'", string)
+    return string
+
+# map keywords to colours
+gcc_keywords = {
+        'error:' : 'error',
+        'warning:' : 'warning',
+        'note:' : 'note',
+        'instantiated from' : 'intro',
+        'undefined reference' : 'error',
+        'multiple definition of' : 'error',
+        }
+
+def keyword_map(string, mapdict):
+    ''' Colourises keywords in a string '''
+    for k in mapdict:
+        string = string.replace(k, wrap_colour(k, mapdict[k]))
+    return string
+
+def colour_filename(filename):
+    ''' Part-colourises a filename.
+        (Muddle paths are often quite long and dangly, and we generally aren't
+        interested in all of them.)
+    '''
+    parts = filename.split('/')
+    # We'll colour up to 3 components.
+    limit = min(3, len(parts))
+    for i in range(-limit,0):
+        parts[i] = wrap_colour(parts[i], 'filename')
+    return '/'.join(parts)
+
+def colour_gcc(reresult):
+    ''' Colourises gcc and gcc-like output.
+        @reresult@ is a regexp match.
+        groups 1 and 2 are filename and line number.
+        group 3 is the position in the line, may not be present.
+        group 4 is the rest of the line - scan for keywords and smart quotes.
+    '''
+    (filename, lineno, linepos, msg) = reresult.group(1,2,3,4)
+    if linepos is not None:
+        linepos = wrap_colour(linepos, 'line_pos') + ':'
+    else:
+        linepos = ''
+    msg = keyword_map(msg, gcc_keywords)
+    msg = colour_quote(msg, 'quoted')
+    return colour_filename(filename) + ':' + wrap_colour(lineno, 'line_num') + ':' + linepos + msg
+
+def colour_one_line(l):
+    # Deal with most gcc and gcc-like output, including linker errors:
+    result = re.search(r'^(.+?\.[^:/ ]+):([0-9]+):([0-9]+)?:?(.*)$', l) # file:line[:pos]:msg
+    if result:
+        return colour_gcc(result)
+    # Otherwise, look for introductions: In function 'int blah(void)':
+    return colour_quote(l, 'introquote')
+
+def colourize(msg):
+    ''' Colourizes a multi-line message '''
+    sw = os.getenv('MUDDLE_COLOURISE', 'auto')
+    if sw=='auto':
+        sw = '1' if sys.stdout.isatty() else '0'
+    if not (sw.lower() in ('yes','y','true','1','html')):
+        # we're not enabled, do nothing
+        return msg
+    output = []
+    if not have_colour:
+        return str(msg) + '''
+
+(muddle says: By the way, I would have colourised this output but you don\'t
+ have the colorama package installed.
+ `apt install python-colorama' or `pip install colorama' to make it work.
+ Or set MUDDLE_COLOURISE=no in your environment to shut this message up.)'''
+
+    lines = str(msg).splitlines(True)
+    output = []
+    for l in lines:
+        output.append( colour_one_line(l.strip()) +'\n')
+    return ''.join(output)

muddled/commands.py

@@ -42,6 +42,7 @@
 import muddled.version_control as version_control
 import muddled.docreport
 
+from muddled.colourize import colourize
 from muddled.db import Database, InstructionFile
 from muddled.depend import Label, label_list_to_string
 from muddled.utils import GiveUp, MuddleBug, Unsupported, \
@@ -848,7 +849,7 @@ def build_labels(builder, to_build):
         for lbl in to_build:
             builder.build_label(lbl)
     except GiveUp,e:
-        raise GiveUp("Can't build %s - %s"%(str(lbl), e))
+        raise GiveUp("Can't build %s - %s"%(str(lbl), colourize(e)))
 
 # =============================================================================
 # Actual commands

sandbox/visualise-dependencies.py

@@ -232,7 +232,7 @@ def process(args):
 		raise GiveUp("None of the given goals %s is a target"%(map(str, goals)))
 
 	for g in full_goals:
-		Node(g, isGoal=True, extras="shape=parallelogram")
+		Node(g, isGoal=True, extras="shape=parallelogram, fillcolor=gold")
 		# color=green fillcolor=green style=filled...?
 
 	for g in full_goals: