Added DelimitedList class, for better handling of naming and diagramming (replaces delimited_list function)

1 files changed, 65 insertions, 0 deletions

diff --git a/pyparsing/core.py b/pyparsing/core.py
index 320d882..5c845ae 100644
--- a/pyparsing/core.py
+++ b/pyparsing/core.py
@@ -5049,6 +5049,71 @@ class ZeroOrMore(_MultipleMatch):
         return "[" + str(self.expr) + "]..."
 
 
+class DelimitedList(ParseElementEnhance):
+    def __init__(
+        self,
+        expr: Union[str, ParserElement],
+        delim: Union[str, ParserElement] = ",",
+        combine: bool = False,
+        min: typing.Optional[int] = None,
+        max: typing.Optional[int] = None,
+        *,
+        allow_trailing_delim: bool = False,
+    ):
+        """Helper to define a delimited list of expressions - the delimiter
+        defaults to ','. By default, the list elements and delimiters can
+        have intervening whitespace, and comments, but this can be
+        overridden by passing ``combine=True`` in the constructor. If
+        ``combine`` is set to ``True``, the matching tokens are
+        returned as a single token string, with the delimiters included;
+        otherwise, the matching tokens are returned as a list of tokens,
+        with the delimiters suppressed.
+
+        If ``allow_trailing_delim`` is set to True, then the list may end with
+        a delimiter.
+
+        Example::
+
+            DelimitedList(Word(alphas)).parse_string("aa,bb,cc") # -> ['aa', 'bb', 'cc']
+            DelimitedList(Word(hexnums), delim=':', combine=True).parse_string("AA:BB:CC:DD:EE") # -> ['AA:BB:CC:DD:EE']
+        """
+        if isinstance(expr, str_type):
+            expr = ParserElement._literalStringClass(expr)
+        expr = typing.cast(ParserElement, expr)
+
+        if min is not None:
+            if min < 1:
+                raise ValueError("min must be greater than 0")
+        if max is not None:
+            if min is not None and max < min:
+                raise ValueError("max must be greater than, or equal to min")
+
+        self.content = expr
+        self.raw_delim = str(delim)
+        self.delim = delim
+        self.combine = combine
+        if not combine:
+            self.delim = Suppress(delim)
+        self.min = min or 1
+        self.max = max
+        self.allow_trailing_delim = allow_trailing_delim
+
+        delim_list_expr = self.content + (self.delim + self.content) * (
+            self.min - 1,
+            None if self.max is None else self.max - 1,
+        )
+        if self.allow_trailing_delim:
+            delim_list_expr += Opt(self.delim)
+
+        if self.combine:
+            delim_list_expr = Combine(delim_list_expr)
+
+        super().__init__(delim_list_expr, savelist=True)
+
+    def _generateDefaultName(self) -> str:
+        return "{0} [{1} {0}]...".format(self.content.streamline(), self.raw_delim)
+
+
 class _NullToken:
     def __bool__(self):
         return False