minirst: support containers

Text can be grouped into generic containers in reStructuredText:

  .. container:: foo

     This is text inside a "foo" container.

     .. container:: bar

        This is nested inside two containers.

The minirst parser now recognizes these containers. The containers are
either pruned completely from the output (included all nested blocks)
or they are simply un-indented. So if 'foo' and 'bar' containers are
kept, the above example will result in:

     This is text inside a "foo" container.

     This is nested inside two containers.

If only 'foo' containers are kept, we get:

     This is text inside a "foo" container.

No output is made if only 'bar' containers are kept.

This feature will come in handy for implementing different levels of
help output (e.g., verbose and debug level help texts).

mercurial/minirst.py

@@ -1,6 +1,6 b''
 # minirst.py - minimal reStructuredText parser
 #
-# Copyright 2009 Matt Mackall <[e-mail]> and others
+# Copyright 2009, 2010 Matt Mackall <[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.
@@ -186,6 +186,42 b' def updatefieldlists(blocks):'
     return blocks
 
 
+def prunecontainers(blocks, keep):
+    """Prune unwanted containers.
+
+    The blocks must have a 'type' field, i.e., they should have been
+    run through findliteralblocks first.
+    """
+    i = 0
+    while i + 1 < len(blocks):
+        # Searching for a block that looks like this:
+        #
+        # +-------+---------------------------+
+        # | ".. container ::" type            |
+        # +---+                               |
+        #     | blocks                        |
+        #     +-------------------------------+
+        if (blocks[i]['type'] == 'paragraph' and
+            blocks[i]['lines'][0].startswith('.. container::')):
+            indent = blocks[i]['indent']
+            adjustment = blocks[i + 1]['indent'] - indent
+            containertype = blocks[i]['lines'][0][15:]
+            prune = containertype not in keep
+
+            # Always delete "..container:: type" block
+            del blocks[i]
+            j = i
+            while j < len(blocks) and blocks[j]['indent'] > indent:
+                if prune:
+                    del blocks[j]
+                    i -= 1 # adjust outer index
+                else:
+                    blocks[j]['indent'] -= adjustment
+                    j += 1
+        i += 1
+    return blocks
+
+
 def findsections(blocks):
     """Finds sections.
 
@@ -281,12 +317,13 b' def formatblock(block, width):'
                          subsequent_indent=subindent)
 
 
-def format(text, width, indent=0):
+def format(text, width, indent=0, keep=[]):
     """Parse and format the text according to width."""
     blocks = findblocks(text)
     for b in blocks:
         b['indent'] += indent
     blocks = findliteralblocks(blocks)
+    blocks = prunecontainers(blocks, keep)
     blocks = inlineliterals(blocks)
     blocks = splitparagraphs(blocks)
     blocks = updatefieldlists(blocks)
@@ -298,8 +335,8 b' def format(text, width, indent=0):'
 if __name__ == "__main__":
     from pprint import pprint
 
-    def debug(func, blocks):
-        blocks = func(blocks)
+    def debug(func, *args):
+        blocks = func(*args)
         print "*** after %s:" % func.__name__
         pprint(blocks)
         print
@@ -308,6 +345,7 b' if __name__ == "__main__":'
     text = open(sys.argv[1]).read()
     blocks = debug(findblocks, text)
     blocks = debug(findliteralblocks, blocks)
+    blocks = debug(prunecontainers, blocks, sys.argv[2:])
     blocks = debug(inlineliterals, blocks)
     blocks = debug(splitparagraphs, blocks)
     blocks = debug(updatefieldlists, blocks)

tests/test-minirst.py

@@ -2,10 +2,10 b''
 
 from mercurial import minirst
 
-def debugformat(title, text, width):
+def debugformat(title, text, width, **kwargs):
     print "%s formatted to fit within %d characters:" % (title, width)
     print "-" * 70
-    print minirst.format(text, width)
+    print minirst.format(text, width, **kwargs)
     print "-" * 70
     print
 
@@ -143,3 +143,25 b' Next list:'
 
 debugformat('fields', fields, 60)
 debugformat('fields', fields, 30)
+
+containers = """
+Normal output.
+
+.. container:: debug
+
+   Initial debug output.
+
+.. container:: verbose
+
+   Verbose output.
+
+   .. container:: debug
+
+      Debug output.
+"""
+
+debugformat('containers (normal)', containers, 60)
+debugformat('containers (verbose)', containers, 60, keep=['verbose'])
+debugformat('containers (debug)', containers, 60, keep=['debug'])
+debugformat('containers (verbose debug)', containers, 60,
+            keep=['verbose', 'debug'])

tests/test-minirst.py.out

@@ -246,3 +246,33 b' much too large'
             own line.
 ----------------------------------------------------------------------
 
+containers (normal) formatted to fit within 60 characters:
+----------------------------------------------------------------------
+Normal output.
+----------------------------------------------------------------------
+
+containers (verbose) formatted to fit within 60 characters:
+----------------------------------------------------------------------
+Normal output.
+
+Verbose output.
+----------------------------------------------------------------------
+
+containers (debug) formatted to fit within 60 characters:
+----------------------------------------------------------------------
+Normal output.
+
+Initial debug output.
+----------------------------------------------------------------------
+
+containers (verbose debug) formatted to fit within 60 characters:
+----------------------------------------------------------------------
+Normal output.
+
+Initial debug output.
+
+Verbose output.
+
+Debug output.
+----------------------------------------------------------------------
+