fix: add initials_separator; fix or-defaulting for format/delimiter kwargs

docs/usage.rst

@@ -203,8 +203,26 @@ Furthermore, the delimiter for the string output can be set through:
 
   >>> HumanName("Doe, John A. Kenneth, Jr.", initials_delimiter=";").initials()
   'J; A; K; D;'
-  >>> HumanName("Doe, John A. Kenneth, Jr.", initials_format="{first}{middle}{last}", initials_delimiter=".").initials()
-  'J.A. K.D.'
+
+The separator between consecutive initials *within* a name group (e.g. two middle
+names) is controlled by :py:attr:`~nameparser.config.Constants.initials_separator`,
+which defaults to ``" "``. Setting it to ``""`` removes that space within a group;
+spacing *between* groups is still governed by ``initials_format``.
+
+``initials_delimiter``, ``initials_separator``, and ``initials_format`` work together:
+
+- ``initials_delimiter`` — appended *after* each individual initial (default ``"."``)
+- ``initials_separator`` — placed *after* the delimiter between consecutive initials in the same group (default ``" "``), so with ``delimiter="."`` and ``separator=" "`` you get ``A. K.``
+- ``initials_format`` — controls how the first, middle, and last groups are arranged
+
+For example, to produce compact period-separated initials with no spaces:
+
+.. doctest:: initials separator
+
+  >>> HumanName("Doe, John A. Kenneth, Jr.", initials_separator="", initials_format="{first}{middle}{last}").initials()
+  'J.A.K.D.'
+  >>> HumanName("Doe, John A. Kenneth, Jr.", initials_delimiter="", initials_separator="", initials_format="{first}{middle}{last}").initials()
+  'JAKD'
 
 To get a list representation of the initials, use :py:meth:`~nameparser.HumanName.initials_list`.
 This function is unaffected by :py:attr:`~nameparser.config.Constants.initials_format`

nameparser/config/__init__.py

@@ -215,6 +215,19 @@ class Constants:
     Will be used to add a delimiter between each initial.
     """
 
+    initials_separator = " "
+    """
+    The default separator placed between consecutive initials within a name
+    group (first, middle, or last). Distinct from ``initials_delimiter``,
+    which is the trailing character after each individual initial.
+
+    With defaults ``initials_delimiter="."`` and ``initials_separator=" "``,
+    ``initials()`` produces ``"J. A. D."``. Setting ``initials_separator=""``
+    with ``initials_delimiter="."`` and ``initials_format="{first}{middle}{last}"``
+    produces ``"J.A.D."``. With the default ``initials_format``, group-level
+    spacing from the template is still applied.
+    """
+
     empty_attribute_default = ''
     """
     Default return value for empty attributes.

nameparser/parser.py

@@ -94,6 +94,7 @@ def __init__(
         string_format: str | None = None,
         initials_format: str | None = None,
         initials_delimiter: str | None = None,
+        initials_separator: str | None = None,
         first: str | list[str] | None = None,
         middle: str | list[str] | None = None,
         last: str | list[str] | None = None,
@@ -106,9 +107,10 @@ def __init__(
             self.C = Constants()
 
         self.encoding = encoding
-        self.string_format = string_format or self.C.string_format
-        self.initials_format = initials_format or self.C.initials_format
-        self.initials_delimiter = initials_delimiter or self.C.initials_delimiter
+        self.string_format      = string_format      if string_format      is not None else self.C.string_format
+        self.initials_format    = initials_format    if initials_format    is not None else self.C.initials_format
+        self.initials_delimiter = initials_delimiter if initials_delimiter is not None else self.C.initials_delimiter
+        self.initials_separator = initials_separator if initials_separator is not None else self.C.initials_separator
         if (first or middle or last or title or suffix or nickname):
             self.first = first
             self.middle = middle
@@ -177,7 +179,7 @@ def __next__(self) -> str:
             return getattr(self, self._members[c]) or next(self)
 
     def __str__(self) -> str:
-        if self.string_format:
+        if self.string_format is not None:
             # string_format = "{title} {first} {middle} {last} {suffix} ({nickname})"
             _s = self.string_format.format(**self.as_dict())
             # remove trailing punctuation from missing nicknames
@@ -241,7 +243,7 @@ def __process_initial__(self, name_part: str, firstname: bool = False) -> str:
                 if not (self.is_prefix(part) or self.is_conjunction(part)) or firstname:
                     initials.append(part[0])
         if len(initials) > 0:
-            return " ".join(initials)
+            return self.initials_separator.join(initials)
         else:
             return self.C.empty_attribute_default
 
@@ -265,19 +267,25 @@ def initials_list(self) -> list[str]:
 
     def initials(self) -> str:
         """
-            Return period-delimited initials of the first, middle and optionally last name.
+        Return formatted initials for the name, controlled by
+        ``initials_format``, ``initials_delimiter``, and ``initials_separator``.
 
-            :param bool include_last_name: Include the last name as part of the initials
-            :rtype: str
+        ``initials_delimiter`` is appended after each individual initial.
+        ``initials_separator`` is placed between consecutive initials within
+        a name group (first, middle, or last). Both can be set as
+        ``Constants`` attributes or as ``HumanName`` constructor kwargs.
 
-            .. doctest::
+        .. doctest::
 
-                >>> name = HumanName("Sir Bob Andrew Dole")
-                >>> name.initials()
-                "B. A. D."
-                >>> name = HumanName("Sir Bob Andrew Dole", initials_format="{first} {middle}")
-                >>> name.initials()
-                "B. A."
+            >>> name = HumanName("Sir Bob Andrew Dole")
+            >>> name.initials()
+            "B. A. D."
+            >>> name = HumanName("Sir Bob Andrew Dole", initials_format="{first} {middle}")
+            >>> name.initials()
+            "B. A."
+            >>> name = HumanName("Doe, John A.", initials_delimiter="", initials_separator="")
+            >>> name.initials()
+            "J A D"
         """
 
         first_initials_list = [self.__process_initial__(name, True) for name in self.first_list if name]
@@ -289,11 +297,11 @@ def initials(self) -> str:
         # output. A fully-empty result falls back to empty_attribute_default,
         # matching the other attribute accessors (e.g. ``first``).
         initials_dict = {
-            "first":  (self.initials_delimiter + " ").join(first_initials_list) + self.initials_delimiter
+            "first":  (self.initials_delimiter + self.initials_separator).join(first_initials_list) + self.initials_delimiter
             if len(first_initials_list) else "",
-            "middle": (self.initials_delimiter + " ").join(middle_initials_list) + self.initials_delimiter
+            "middle": (self.initials_delimiter + self.initials_separator).join(middle_initials_list) + self.initials_delimiter
             if len(middle_initials_list) else "",
-            "last": (self.initials_delimiter + " ").join(last_initials_list) + self.initials_delimiter
+            "last": (self.initials_delimiter + self.initials_separator).join(last_initials_list) + self.initials_delimiter
             if len(last_initials_list) else ""
         }
 

tests/base.py

@@ -39,6 +39,9 @@ def assertFalse(self, expr: object, msg: object = None) -> None:
     def assertIn(self, member: object, container: object, msg: object = None) -> None:
         assert member in container, msg  # type: ignore[operator]
 
+    def assertNotEqual(self, first: object, second: object, msg: object = None) -> None:
+        assert first != second, msg
+
     def assertNotIn(self, member: object, container: object, msg: object = None) -> None:
         assert member not in container, msg  # type: ignore[operator]
 

tests/test_initials.py

@@ -69,10 +69,16 @@ def test_initials_delimiter(self) -> None:
     def test_initials_delimiter_constants(self) -> None:
         from nameparser.config import CONSTANTS
         _orig = CONSTANTS.initials_delimiter
-        CONSTANTS.initials_delimiter = ";"
-        hn = HumanName("Doe, John A. Kenneth, Jr.")
-        self.m(hn.initials(), "J; A; K; D;", hn)
-        CONSTANTS.initials_delimiter = _orig
+        try:
+            CONSTANTS.initials_delimiter = ";"
+            hn = HumanName("Doe, John A. Kenneth, Jr.")
+            self.m(hn.initials(), "J; A; K; D;", hn)
+        finally:
+            CONSTANTS.initials_delimiter = _orig
+
+    def test_initials_separator_default_on_constants(self) -> None:
+        from nameparser.config import CONSTANTS
+        self.assertEqual(CONSTANTS.initials_separator, " ")
 
     def test_initials_list(self) -> None:
         hn = HumanName("Andrew Boris Petersen")
@@ -90,6 +96,44 @@ def test_initials_with_prefix(self) -> None:
         hn = HumanName("Alex van Johnson")
         self.m(hn.initials_list(), ["A", "J"], hn)
 
+    def test_initials_delimiter_empty_string_kwarg(self) -> None:
+        # Regression: initials_delimiter='' was silently ignored due to `or` defaulting
+        hn = HumanName("Doe, John A.", initials_delimiter="")
+        self.m(hn.initials(), "J A D", hn)
+
+    def test_initials_format_empty_string_kwarg(self) -> None:
+        # Regression: initials_format='' was silently ignored due to `or` defaulting
+        hn = HumanName("Doe, John A.")
+        hn2 = HumanName("Doe, John A.", initials_format="")
+        self.assertNotEqual(hn.initials(), hn2.initials())
+        # "".format(...) returns ""; collapse_whitespace returns "" which falls through
+        # to empty_attribute_default (may be "" or None depending on config variant).
+        self.assertFalse(hn2.initials())
+
+    def test_initials_separator_kwarg(self) -> None:
+        # initials_separator="" with initials_format="{first}{middle}{last}" gives
+        # period-separated initials with no spaces — a common academic citation style
+        hn = HumanName(
+            "Doe, John A. Kenneth",
+            initials_separator="",
+            initials_format="{first}{middle}{last}",
+        )
+        self.m(hn.initials(), "J.A.K.D.", hn)
+
+    def test_initials_separator_custom_value(self) -> None:
+        # Non-empty custom separator exercising __process_initial__ on a multi-word
+        # token. "Van Berg" is a single name part whose two words produce two initials
+        # joined by initials_separator.
+        hn = HumanName("", initials_separator="-", initials_delimiter=".")
+        result = hn.__process_initial__("Van Berg", firstname=True)
+        self.assertEqual(result, "V-B")
+
+    def test_str_default_behavior_unchanged(self) -> None:
+        # Regression guard for the `or` → `is not None` change in __str__:
+        # the default path (no string_format kwarg) must still produce the expected string.
+        hn = HumanName("John Doe")
+        self.assertEqual(str(hn), "John Doe")
+
     def test_constructor_first(self) -> None:
         hn = HumanName(first="TheName")
         self.assertFalse(hn.unparsable)
@@ -126,3 +170,43 @@ def test_constructor_multiple(self) -> None:
         self.m(hn.first, "TheName", hn)
         self.m(hn.last, "lastname", hn)
         self.m(hn.title, "mytitle", hn)
+
+    def test_initials_separator_kwarg_multiword_part(self) -> None:
+        # Regression: initials_separator kwarg must flow into __process_initial__
+        # for multi-word name parts, not just into the initials() join calls.
+        hn = HumanName("", initials_separator="")
+        result = hn.__process_initial__("Van Berg", firstname=True)
+        self.assertEqual(result, "VB")
+
+    def test_string_format_empty_string_kwarg(self) -> None:
+        # Regression: string_format='' was silently ignored due to `or` defaulting
+        hn = HumanName("John Doe", string_format="")
+        self.assertEqual(str(hn), "")
+
+    def test_initials_separator_empty_multi_part_middle(self) -> None:
+        # Full workflow from issue #152: empty delimiter + separator + compact format
+        # gives fully concatenated initials with no spaces or punctuation.
+        # Spaces between groups come from initials_format, so that must also be set.
+        hn = HumanName(
+            "Doe, John A. Kenneth",
+            initials_delimiter="",
+            initials_separator="",
+            initials_format="{first}{middle}{last}",
+        )
+        self.m(hn.initials(), "JAKD", hn)
+
+    def test_initials_separator_constants_multi_part_middle(self) -> None:
+        from nameparser.config import CONSTANTS
+        _orig_d = CONSTANTS.initials_delimiter
+        _orig_s = CONSTANTS.initials_separator
+        _orig_f = CONSTANTS.initials_format
+        try:
+            CONSTANTS.initials_delimiter = ""
+            CONSTANTS.initials_separator = ""
+            CONSTANTS.initials_format = "{first}{middle}{last}"
+            hn = HumanName("Doe, John A. Kenneth")
+            self.m(hn.initials(), "JAKD", hn)
+        finally:
+            CONSTANTS.initials_delimiter = _orig_d
+            CONSTANTS.initials_separator = _orig_s
+            CONSTANTS.initials_format = _orig_f