docchecker: report context line at most once

doc/docchecker

@@ -1,54 +1,61 b''
 #!/usr/bin/env python
 #
 # docchecker - look for problematic markup
 #
 # Copyright 2016 timeless <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 import sys
 import re
 
 leadingline = re.compile(r'(^\s*)(\S.*)$')
-hg_backtick = re.compile(r""":hg:`[^`]*'[^`]*`""")
-hg_cramped = re.compile(r'\w:hg:`')
+
+checks = [
+  (r""":hg:`[^`]*'[^`]*`""",
+    """warning: please avoid nesting ' in :hg:`...`"""),
+  (r'\w:hg:`',
+    'warning: please have a space before :hg:'),
+]
 
 def check(line):
-    if hg_backtick.search(line):
+    messages = []
+    for match, msg in checks:
+        if re.search(match, line):
+            messages.append(msg)
+    if messages:
         print(line)
-        print("""warning: please avoid nesting ' in :hg:`...`""")
-    if hg_cramped.search(line):
-        print(line)
-        print('warning: please have a space before :hg:')
+        for msg in messages:
+            print(msg)
 
 def work(file):
     (llead, lline) = ('', '')
 
     for line in file:
         # this section unwraps lines
         match = leadingline.match(line)
         if not match:
             check(lline)
             (llead, lline) = ('', '')
             continue
 
         lead, line = match.group(1), match.group(2)
         if (lead == llead):
             if (lline != ''):
                 lline += ' ' + line
             else:
                 lline = line
         else:
             check(lline)
             (llead, lline) = (lead, line)
     check(lline)
 
 def main():
     for f in sys.argv[1:]:
         try:
             with open(f) as file:
                 work(file)
         except BaseException as e:
             print("failed to process %s: %s" % (f, e))
 
 main()