Added LIMIT operator and more tests

src/rpn/__init__.py

@@ -15,6 +15,12 @@ def __call__(self, tokens, pos):
 		return tokens
 
 
+def operator_limit(value, low, high):
+	if low <= value <= high:
+		return value
+	return None
+
+
 OPERATORS = {
 	# MATH
 	'+': RPNOperator(operator.add, 2),
@@ -37,6 +43,8 @@ def __call__(self, tokens, pos):
 	# COMPARE
 	'MIN': RPNOperator(min, 2),
 	'MAX': RPNOperator(max, 2),
+	# MINNAN, MAXNAN
+	'LIMIT': RPNOperator(operator_limit, 3),
 }
 
 class RPN(object):

tests/test_compare.py

@@ -15,3 +15,12 @@ def test_max(self):
 
 		assert r.calc('1 2 MAX') == 2
 		assert r.calc('3 2 MAX') == 3
+
+	def test_limit(self):
+		r = RPN()
+
+		assert r.calc('1 1 10 LIMIT') == 1
+		assert r.calc('10 1 10 LIMIT') == 10
+		assert r.calc('0 1 10 LIMIT') is None
+		assert r.calc('-1 1 10 LIMIT') is None
+		assert r.calc('100 1 10 LIMIT') is None

tests/test_complex.py

@@ -0,0 +1,9 @@
+# -*- coding: utf-8 -*-
+from rpn import RPN
+
+
+class TestComplex(object):
+
+	def test_complex(self):
+		r = RPN()
+		assert r.calc('3 4 2 * 1 5 - 2 3 ^ ^ / +') == 3.0001220703125