positive and negative predicates

js-assembler/runtime-src/baselib-primitives.js

@@ -1298,6 +1298,24 @@
         });
 
 
+    installPrimitiveProcedure(
+        'positive?',
+        1,
+        function(MACHINE) {
+            var n = checkReal(MACHINE, 'positive?', 0);
+            return baselib.numbers.greaterThan(n, 0);
+        });
+
+    installPrimitiveProcedure(
+        'negative?',
+        1,
+        function(MACHINE) {
+            var n = checkReal(MACHINE, 'negative?', 0);
+            return baselib.numbers.lessThan(n, 0);
+        });
+
+
+
 
 
 

lang/kernel.rkt

@@ -315,8 +315,8 @@ exact-nonnegative-integer?
 odd?
 even?
 zero?
-;;  positive?
+positive?
-;;  negative?
+negative?
 ;;  box?
 ;;  hash?
 

tests/more-tests/numbers.expected

@@ -15,3 +15,17 @@ false
 1
 3
 3
+false
+false
+true
+false
+false
+true
+true
+false
+false
+true
+true
+false
+false
+true

tests/more-tests/numbers.rkt

@@ -20,3 +20,19 @@
 (min 3 1 4 1 5 9 2 6)
 (min 3 20)
 (min 20 3)
+
+
+(positive? 0)
+(negative? 0)
+(positive? 42)
+(negative? 42)
+(positive? -42)
+(negative? -42)
+(positive? 3.1415926)
+(negative? 3.1415926)
+(positive? -3.1415926)
+(negative? -3.1415926)
+(positive? (expt 2 100))
+(negative? (expt 2 100))
+(positive? (expt -2 91))
+(negative? (expt -2 91))