# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1493329363 -7200
# Node ID 0cbb97f958954a7835d01b33203abd78baa86031
# Parent  863171f41eacadb3e30c1f2283b4cebcf0596619
Consolidated region parsing further, adding a mechanism of invoking handlers
corresponding to the patterns encountered.

diff -r 863171f41eac -r 0cbb97f95895 moinformat.py
--- a/moinformat.py	Thu Apr 27 23:15:30 2017 +0200
+++ b/moinformat.py	Thu Apr 27 23:42:43 2017 +0200
@@ -54,6 +54,8 @@
     def append(self, node):
         self.nodes.append(node)
 
+    append_text = append
+
     def normalise(self):
 
         "Combine adjacent text nodes."
@@ -102,6 +104,12 @@
         self.level = level
         self.type = type
 
+    def append_text(self, s):
+        if self.is_transparent():
+            self.nodes[-1].append(s)
+        else:
+            self.append(s)
+
     def have_end(self, s):
         return self.level and s.startswith("}") and self.level == len(s)
 
@@ -312,6 +320,8 @@
 
     parse_region_header(items, region)
 
+    # Parse section body.
+
     if region.is_transparent():
         parse_region_wiki(items, region)
     else:
@@ -332,103 +342,94 @@
 
     "Parse the data provided by 'items' to populate a wiki 'region'."
 
-    # Process exposed text and sections.
-
-    block = new_block(region)
+    new_block(region)
+    parse_region_details(items, region, ["break", "regionstart", "regionend"])
 
-    while True:
+def parse_region_opaque(items, region):
 
-        # Obtain text before any marker or the end of the input.
+    "Parse the data provided by 'items' to populate an opaque 'region'."
+
+    parse_region_details(items, region, ["regionend"])
 
-        preceding = items.read_until(["break", "regionstart", "regionend"])
-        if preceding:
-            block.append(Text(preceding))
+def parse_region_details(items, region, pattern_names):
 
-        # Obtain any feature.
+    "Parse 'items' within 'region' searching using 'pattern_names'."
 
-        feature = items.read_match()
+    try:
+        while True:
 
-        # End of input.
-
-        if not items.matching:
-            break
+            # Obtain text before any marker or the end of the input.
 
-        # Start a section if an appropriate marker is given.
+            preceding = items.read_until(pattern_names)
+            if preceding:
+                region.append_text(Text(preceding))
 
-        if items.matching == "regionstart":
-            block = parse_region_within_wiki_region(items, region)
+            # End of input.
 
-        # Interpret the given marker, closing the current section if the
-        # given marker is the corresponding end marker for the current
-        # section.
+            if not items.matching:
+                break
+
+            # Obtain any feature.
 
-        elif items.matching == "regionend" and region.have_end(feature):
-            break
+            feature = items.read_match()
+            handler = handlers.get(items.matching)
 
-        # Start a new block if a paragraph break is found.
+            # Handle each feature or add text to the region.
 
-        elif items.matching == "break":
-            block = parse_block(items, region)
+            if handler:
+                handler(items, region)
+            else:
+                region.append_text(Text(feature))
 
-        # Add any inappropriate marker to the text.
-
-        else:
-            block.append(Text(feature))
+    except StopIteration:
+        pass
 
     region.normalise()
 
-def parse_region_within_wiki_region(items, region):
+def end_region(items, region):
 
-    # Parse the section and start a new block after the section.
+    "End the parsing of 'region'."
 
-    feature = items.read_match()
-    region.append(parse_region(items, len(feature)))
-    return new_block(region)
+    raise StopIteration
 
-def parse_block(items, region):
+def parse_break(items, region):
+
+    "Handle a paragraph break within 'region'."
 
     # Mark any previous block as not being the final one in a sequence.
 
     block = region.nodes[-1]
     block.final = False
-    return new_block(region)
-
-def parse_region_opaque(items, region):
+    new_block(region)
 
-    "Parse the data provided by 'items' to populate an opaque 'region'."
+def parse_section(items, region):
 
-    # Process exposed text and the section end.
+    "Handle the start of a new section within 'region'."
 
-    while True:
-
-        # Obtain text before any marker or the end of the input.
+    # Parse the section and start a new block after the section.
 
-        preceding = items.read_until(["regionend"])
-        if preceding:
-            region.append(Text(preceding))
+    level = len(items.read_match())
+    region.append(parse_region(items, level))
+    new_block(region)
 
-        # Obtain any marker.
+def parse_section_end(items, region):
 
-        marker = items.read_match()
+    "Handle the end of a new section within 'region'."
 
-        # End of input.
-
-        if not marker:
-            break
+    feature = items.read_match()
+    if region.have_end(feature):
+        raise StopIteration
+    else:
+        region.append_text(Text(feature))
 
-        # Interpret the given marker, closing the current section if the
-        # given marker is the corresponding end marker for the current
-        # section.
-
-        if region.have_end(marker):
-            break
+# Pattern handlers.
 
-        # Add any inappropriate marker to the text.
-
-        else:
-            region.append(Text(marker))
-
-    region.normalise()
+handlers = {
+    None : end_region,
+    "break" : parse_break,
+    "regionstart" : parse_section,
+    "regionend" : parse_section_end,
+    }
 
 def new_block(region):
 
@@ -436,7 +437,6 @@
 
     block = Block([])
     region.append(block)
-    return block