+odd and even checks

orsinium · orsinium · commit e66762126db2 · 2019-06-03T18:12:11.000+02:00
diff --git a/lambdas.py b/lambdas.py
@@ -87,6 +87,8 @@
     (lambda _: ADD(f(DEC(n)))(f(DEC(DEC(n)))))
     (ZERO)
 )
+
+# more arithmetic
 DIV = Y(
     lambda f: lambda a: lambda b: LT(a)(b)
     (lambda _: ZERO)
@@ -99,6 +101,8 @@
     (lambda _: f(SUB(a)(b))(b))
     (ZERO)
 )
+EVEN = lambda a: ISZERO(MOD(a)(TWO))
+ODD  = lambda a: NOT(EVEN(a))
 
 
 # helpers
