util.py: list_gen(): support inclusion of multiple members, add test

mmgen/util.py

@@ -190,15 +190,20 @@ def fmt_list(iterable,fmt='dfl',indent=''):
 
 def list_gen(*data):
 	"""
-	add element to list if condition is true or absent
+	Generate a list from an arg tuple of sublists
+	- The last element of each sublist is a condition.  If it evaluates to true, the preceding
+	  elements of the sublist are included in the result.  Otherwise the sublist is skipped.
+	- If a sublist contains only one element, the condition defaults to true.
 	"""
 	assert type(data) in (list,tuple), f'{type(data).__name__} not in (list,tuple)'
 	def gen():
-		for i in data:
-			assert type(i) == list, f'{type(i).__name__} != list'
-			assert len(i) in (1,2), f'{len(i)} not in (1,2)'
-			if len(i) == 1 or i[1]:
-				yield i[0]
+		for d in data:
+			assert type(d) == list, f'{type(d).__name__} != list'
+			if len(d) == 1:
+				yield d[0]
+			elif d[-1]:
+				for idx in range(len(d)-1):
+					yield d[idx]
 	return list(gen())
 
 def remove_dups(iterable,edesc='element',desc='list',quiet=False,hide=False):

test/unit_tests_d/ut_util.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+
+"""
+test.unit_tests_d.ut_misc: utility unit tests for the MMGen suite
+"""
+
+from ..include.common import vmsg
+from mmgen.util import list_gen
+
+class unit_tests:
+
+	def list_gen(self,name,ut):
+		res = list_gen(
+			['a'],
+			['b', 1==2],
+			['c', 'x'],
+			['d', int],
+			['e', None, 1, 'f', isinstance(7,int)],
+			['g', 'h', 0],
+			[None],
+			[0],
+			[False],
+		)
+		chk = ['a', 'c', 'd', 'e', None, 1, 'f', None, 0, False]
+
+		vmsg('=> ' + str(res))
+		assert res == chk, f'{res} != {chk}'
+		vmsg('')
+		return True