Merge pull request #3421 from InspectorCaracal/refactor-object-display

Removes need for hardcoding line breaks into display hooks

evennia/objects/objects.py

@@ -31,6 +31,7 @@ from evennia.utils.utils import (
     iter_to_str,
     lazy_property,
     make_iter,
+    compress_whitespace,
     to_str,
     variable_from_module,
 )
@@ -221,7 +222,9 @@ class DefaultObject(ObjectDB, metaclass=TypeclassBase):
 {header}
 |c{name}{extra_name_info}|n
 {desc}
-{exits}{characters}{things}
+{exits}
+{characters}
+{things}
 {footer}
     """
     # on-object properties
@@ -1585,7 +1588,7 @@ class DefaultObject(ObjectDB, metaclass=TypeclassBase):
             char.get_display_name(looker, **kwargs) for char in characters
         )
 
-        return f"\n|wCharacters:|n {character_names}" if character_names else ""
+        return f"|wCharacters:|n {character_names}" if character_names else ""
 
     def get_display_things(self, looker, **kwargs):
         """
@@ -1616,7 +1619,7 @@ class DefaultObject(ObjectDB, metaclass=TypeclassBase):
             singular, plural = thing.get_numbered_name(nthings, looker, key=thingname)
             thing_names.append(singular if nthings == 1 else plural)
         thing_names = iter_to_str(thing_names)
-        return f"\n|wYou see:|n {thing_names}" if thing_names else ""
+        return f"|wYou see:|n {thing_names}" if thing_names else ""
 
     def get_display_footer(self, looker, **kwargs):
         """
@@ -1643,7 +1646,7 @@ class DefaultObject(ObjectDB, metaclass=TypeclassBase):
             str: The final formatted output.
 
         """
-        return appearance.strip()
+        return compress_whitespace(appearance).strip()
 
     def return_appearance(self, looker, **kwargs):
         """

evennia/utils/tests/test_utils.py

@@ -53,6 +53,31 @@ class TestDedent(TestCase):
         self.assertEqual(expected_string, utils.dedent(input_string))
 
 
+class TestCompressWhitespace(TestCase):
+    def test_compress_whitespace(self):
+        # No text, return no text
+        self.assertEqual("", utils.compress_whitespace(""))
+        # If no whitespace is exceeded, should return the same
+        self.assertEqual("One line\nTwo  spaces", utils.compress_whitespace("One line\nTwo  spaces"))
+        # Extra newlines are removed
+        self.assertEqual("First line\nSecond line", utils.compress_whitespace("First line\n\nSecond line"))
+        # Extra spaces are removed
+        self.assertEqual("Too  many  spaces", utils.compress_whitespace("Too   many      spaces"))
+        # "Invisible" extra lines with whitespace are removed
+        self.assertEqual("First line\nSecond line", utils.compress_whitespace("First line\n    \n \nSecond line"))
+        # Max kwargs are respected
+        self.assertEqual("First line\n\nSecond line", utils.compress_whitespace("First line\n\nSecond  line", max_spacing=1, max_linebreaks=2))
+
+    def test_preserve_indents(self):
+        """Ensure that indentation spacing is preserved."""
+        indented = """\
+Hanging Indents
+    they're great
+    let's keep them\
+"""
+        # since there is no doubled-up spacing besides indents, input should equal output
+        self.assertEqual(indented, utils.compress_whitespace(indented))
+
 class TestListToString(TestCase):
     """
     Default function header from time.py:

evennia/utils/utils.py

@@ -472,6 +472,31 @@ def iter_to_str(iterable, sep=",", endsep=", and", addquote=False):
 list_to_string = iter_to_str
 iter_to_string = iter_to_str
 
+re_empty = re.compile("\n\s*\n")
+
+def compress_whitespace(text, max_linebreaks=1, max_spacing=2):
+    """
+    Removes extra sequential whitespace in a block of text. This will also remove any trailing
+    whitespace at the end.
+
+    Args:
+        text (str):   A string which may contain excess internal whitespace.
+
+    Keyword args:
+        max_linebreaks (int):  How many linebreak characters are allowed to occur in a row.
+        max_spacing (int):     How many spaces are allowed to occur in a row.
+
+    """
+    text = text.rstrip()
+    # replaces any non-visible lines that are just whitespace characters with actual empty lines
+    # this allows the blank-line compression to eliminate them if needed
+    text = re_empty.sub("\n\n", text)
+    # replace groups of extra spaces with the maximum number of spaces
+    text = re.sub(f"(?<=\S) {{{max_spacing},}}", " "*max_spacing, text)
+    # replace groups of extra newlines with the maximum number of newlines
+    text = re.sub(f"\n{{{max_linebreaks},}}", "\n"*max_linebreaks, text)
+    return text
+
 
 def wildcard_to_regexp(instring):
     """