Make Template.remove(keep_field=True) slightly more reasonable.

CHANGELOG

@@ -1,6 +1,8 @@
 v0.5 (unreleased):
 
-- Fixed Wikicode.matches() on iterables besides lists and tuples.
+- Made Template.remove(keep_field=True) behave more reasonably when the
+  parameter is already empty.
+- Fixed Wikicode.matches()'s behavior on iterables besides lists and tuples.
 - Fixed len() sometimes raising ValueError on empty node lists.
 - Fixed release script after changes to PyPI.
 

docs/changelog.rst

@@ -7,7 +7,10 @@ v0.5
 Unreleased
 (`changes <https://github.com/earwig/mwparserfromhell/compare/v0.4.4...develop>`__):
 
-- Fixed :meth:`.Wikicode.matches` on iterables besides lists and tuples.
+- Made :meth:`Template.remove(keep_field=True) <.Template.remove>` behave more
+  reasonably when the parameter is already empty.
+- Fixed :meth:`.Wikicode.matches`\ 's behavior on iterables besides lists and
+  tuples.
 - Fixed ``len()`` sometimes raising ``ValueError`` on empty node lists.
 - Fixed release script after changes to PyPI.
 

mwparserfromhell/nodes/template.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8  -*-
 #
-# Copyright (C) 2012-2016 Ben Kurtovic <ben.kurtovic@gmail.com>
+# Copyright (C) 2012-2017 Ben Kurtovic <ben.kurtovic@gmail.com>
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -70,7 +70,8 @@ class Template(Node):
             get(param.value)
         write("}}")
 
-    def _surface_escape(self, code, char):
+    @staticmethod
+    def _surface_escape(code, char):
         """Return *code* with *char* escaped as an HTML entity.
 
         The main use of this is to escape pipes (``|``) or equal signs (``=``)
@@ -82,7 +83,8 @@ class Template(Node):
             if char in node:
                 code.replace(node, node.replace(char, replacement), False)
 
-    def _select_theory(self, theories):
+    @staticmethod
+    def _select_theory(theories):
         """Return the most likely spacing convention given different options.
 
         Given a dictionary of convention options as keys and their occurrence
@@ -96,6 +98,22 @@ class Template(Node):
             if confidence >= 0.75:
                 return tuple(theories.keys())[values.index(best)]
 
+    @staticmethod
+    def _blank_param_value(value):
+        """Remove the content from *value* while keeping its whitespace.
+
+        Replace *value*\ 's nodes with two text nodes, the first containing
+        whitespace from before its content and the second containing whitespace
+        from after its content.
+        """
+        sval = str(value)
+        if sval.isspace():
+            before, after = "", sval
+        else:
+            match = re.search(r"^(\s*).*?(\s*)$", sval, FLAGS)
+            before, after = match.group(1), match.group(2)
+        value.nodes = [Text(before), Text(after)]
+
     def _get_spacing_conventions(self, use_names):
         """Try to determine the whitespace conventions for parameters.
 
@@ -119,16 +137,6 @@ class Template(Node):
         after = self._select_theory(after_theories)
         return before, after
 
-    def _blank_param_value(self, value):
-        """Remove the content from *value* while keeping its whitespace.
-
-        Replace *value*\ 's nodes with two text nodes, the first containing
-        whitespace from before its content and the second containing whitespace
-        from after its content.
-        """
-        match = re.search(r"^(\s*).*?(\s*)$", str(value), FLAGS)
-        value.nodes = [Text(match.group(1)), Text(match.group(2))]
-
     def _fix_dependendent_params(self, i):
         """Unhide keys if necessary after removing the param at index *i*."""
         if not self.params[i].showkey:

tests/test_template.py

@@ -216,6 +216,7 @@ class TestTemplate(TreeEqualityTestCase):
         node39 = Template(wraptext("a"), [pgenh("1", " b ")])
         node40 = Template(wraptext("a"), [pgenh("1", " b"), pgenh("2", " c")])
         node41 = Template(wraptext("a"), [pgens("1", " b"), pgens("2", " c")])
+        node42 = Template(wraptext("a"), [pgens("b", "  \n")])
 
         node1.add("e", "f", showkey=True)
         node2.add(2, "g", showkey=False)
@@ -261,6 +262,7 @@ class TestTemplate(TreeEqualityTestCase):
         node39.add("1", "c")
         node40.add("3", "d")
         node41.add("3", "d")
+        node42.add("b", "hello")
 
         self.assertEqual("{{a|b=c|d|e=f}}", node1)
         self.assertEqual("{{a|b=c|d|g}}", node2)
@@ -308,6 +310,7 @@ class TestTemplate(TreeEqualityTestCase):
         self.assertEqual("{{a|c}}", node39)
         self.assertEqual("{{a| b| c|d}}", node40)
         self.assertEqual("{{a|1= b|2= c|3= d}}", node41)
+        self.assertEqual("{{a|b=hello  \n}}", node42)
 
     def test_remove(self):
         """test Template.remove()"""