Merge pull request #59 from skx/53-inequality

Added /= function.

PRIMITIVES.md

@@ -72,6 +72,8 @@ Things you'll find here include:
 * `/`
   * Division function.
   * Note that if only a single value is specified the reciprocal is returned - i.e. "(/ 3)" is equal to "1/3".
+* `/=`
+  * Numerical inequality test, if any argument is the same as another return false, otherwise if all arguments are unique return true.
 * `<`
   * Less-than function.
 * `=`

builtins/builtins.go

@@ -96,7 +96,8 @@ func PopulateEnvironment(env *env.Environment) {
 	env.Set("*", &primitive.Procedure{F: multiplyFn, Help: helpMap["*"], Args: []primitive.Symbol{primitive.Symbol("N"), primitive.Symbol("arg1..argN")}})
 	env.Set("+", &primitive.Procedure{F: plusFn, Help: helpMap["+"], Args: []primitive.Symbol{primitive.Symbol("N"), primitive.Symbol("arg1..argN")}})
 	env.Set("-", &primitive.Procedure{F: minusFn, Help: helpMap["-"], Args: []primitive.Symbol{primitive.Symbol("N"), primitive.Symbol("arg1..argN")}})
-	env.Set("/", &primitive.Procedure{F: divideFn, Help: helpMap["-"], Args: []primitive.Symbol{primitive.Symbol("N"), primitive.Symbol("arg1..argN")}})
+	env.Set("/", &primitive.Procedure{F: divideFn, Help: helpMap["/"], Args: []primitive.Symbol{primitive.Symbol("N"), primitive.Symbol("arg1..argN")}})
+	env.Set("/=", &primitive.Procedure{F: inequalityFn, Help: helpMap["/="], Args: []primitive.Symbol{primitive.Symbol("N"), primitive.Symbol("arg1..argN")}})
 	env.Set("<", &primitive.Procedure{F: ltFn, Help: helpMap["<"], Args: []primitive.Symbol{primitive.Symbol("a"), primitive.Symbol("b")}})
 	env.Set("=", &primitive.Procedure{F: equalsFn, Help: helpMap["="], Args: []primitive.Symbol{primitive.Symbol("arg1"), primitive.Symbol("arg2 .. argN")}})
 	env.Set("arch", &primitive.Procedure{F: archFn, Help: helpMap["arch"]})
@@ -786,6 +787,53 @@ func helpFn(env *env.Environment, args []primitive.Primitive) primitive.Primitiv
 	return primitive.String(str)
 }
 
+// inequalityFn implements /=
+func inequalityFn(env *env.Environment, args []primitive.Primitive) primitive.Primitive {
+
+	// We need at least two arguments
+	if len(args) < 2 {
+		return primitive.ArityError()
+	}
+
+	// First argument must be a number.
+	nA, ok := args[0].(primitive.Number)
+	if !ok {
+		return primitive.Error("argument was not a number")
+	}
+
+	// Now we'll loop over all other numbers
+	//
+	// If we got something that was already seen we can
+	// terminate early but we don't because it is important
+	// to also report on failures to validate types - which
+	// we can't do if we bail.
+	//
+	ret := primitive.Bool(true)
+
+	// Keep track of things we've seen here
+	seen := make(map[float64]bool)
+	seen[float64(nA)] = true
+
+	for _, i := range args[1:] {
+
+		// check we have a number
+		nB, ok2 := i.(primitive.Number)
+
+		if !ok2 {
+			return primitive.Error("argument was not a number")
+		}
+
+		// Have we seen this?
+		_, found := seen[float64(nB)]
+		if found {
+			ret = primitive.Bool(false)
+		}
+		seen[float64(nB)] = true
+	}
+
+	return ret
+}
+
 // (join (1 2 3)
 func joinFn(env *env.Environment, args []primitive.Primitive) primitive.Primitive {
 

builtins/builtins_test.go

@@ -1610,6 +1610,115 @@ func TestHelp(t *testing.T) {
 	}
 }
 
+// TestInequality tests /=
+func TestInequality(t *testing.T) {
+
+	// No arguments
+	out := inequalityFn(ENV, []primitive.Primitive{})
+
+	// Will lead to an error
+	e, ok := out.(primitive.Error)
+	if !ok {
+		t.Fatalf("expected error, got %v", out)
+	}
+	if e != primitive.ArityError() {
+		t.Fatalf("got error, but wrong one %v", out)
+	}
+
+	//
+	// Now a real one: unequal
+	//
+	out = inequalityFn(ENV, []primitive.Primitive{
+		primitive.Number(9),
+		primitive.Number(8),
+	})
+
+	// Will work
+	n, ok2 := out.(primitive.Bool)
+	if !ok2 {
+		t.Fatalf("expected bool, got %v", out)
+	}
+	if n != true {
+		t.Fatalf("got wrong result")
+	}
+
+	//
+	// Now a real one: unequal - but multiple values
+	//
+	out = inequalityFn(ENV, []primitive.Primitive{
+		primitive.Number(1),
+		primitive.Number(2),
+		primitive.Number(3),
+		primitive.Number(4),
+		primitive.Number(5),
+		primitive.Number(6),
+	})
+
+	// Will work
+	n, ok2 = out.(primitive.Bool)
+	if !ok2 {
+		t.Fatalf("expected bool, got %v", out)
+	}
+	if n != true {
+		t.Fatalf("got wrong result")
+	}
+
+	//
+	// Now a real one: unequal values
+	//
+	out = inequalityFn(ENV, []primitive.Primitive{
+		primitive.Number(1),
+		primitive.Number(2),
+		primitive.Number(2),
+		primitive.Number(1),
+	})
+
+	// Will work
+	n, ok2 = out.(primitive.Bool)
+	if !ok2 {
+		t.Fatalf("expected bool, got %v", out)
+	}
+	if n != false {
+		t.Fatalf("got wrong result")
+	}
+
+	//
+	// Now with wrong types - last one is wrong
+	//
+	out = inequalityFn(ENV, []primitive.Primitive{
+		primitive.Number(1),
+		primitive.Number(2),
+		primitive.Number(3),
+		primitive.Number(4),
+		primitive.String("5"),
+	})
+
+	e, ok = out.(primitive.Error)
+	if !ok {
+		t.Fatalf("expected error, got %v", out)
+	}
+	if !strings.Contains(string(e), "was not a number") {
+		t.Fatalf("got error, but wrong one '%v'", e)
+	}
+
+	//
+	// Now with wrong types
+	//
+	out = inequalityFn(ENV, []primitive.Primitive{
+		primitive.String("9"),
+		primitive.Number(9),
+	})
+
+	// Will report an error
+	e, ok = out.(primitive.Error)
+	if !ok {
+		t.Fatalf("expected error, got %v", out)
+	}
+	if !strings.Contains(string(e), "was not a number") {
+		t.Fatalf("got error, but wrong one %v", out)
+	}
+}
+
 // TestJoin tests join
 func TestJoin(t *testing.T) {
 

builtins/help.txt

@@ -16,6 +16,10 @@ Multiplies all arguments present with the first number.
 /
 Divides all arguments present with the first number.
 %%
+/=
+Numerical inequality testing.   If any argument is identical
+to any other argument return false.  Otherwise return true.
+%%
 <
 
 Return true if a is less than b.

eval/eval_test.go

@@ -187,7 +187,6 @@ a
 		//
 		{"(+ 3)", "3"},
 		{"(- 3)", "3"},
-		{"(/ 3)", "3"},
 		{"(* 3)", "3"},
 
 		// strings
@@ -358,12 +357,12 @@ func TestStandardLibrary(t *testing.T) {
 			output: "(1 4 9 16 25)"},
 
 		// range
-		{input: "(range -5 5 1)", output: "(-5 -4 -3 -2 -1 0 1 2 3 4)"},
-		{input: "(range 1 11 2)", output: "(1 3 5 7 9)"},
+		{input: "(range -5 5 1)", output: "(-5 -4 -3 -2 -1 0 1 2 3 4 5)"},
+		{input: "(range 1 11 2)", output: "(1 3 5 7 9 11)"},
 
 		// seq/nat
-		{input: "(seq 10)", output: "(0 1 2 3 4 5 6 7 8 9)"},
-		{input: "(nat 10)", output: "(1 2 3 4 5 6 7 8 9)"},
+		{input: "(seq 10)", output: "(0 1 2 3 4 5 6 7 8 9 10)"},
+		{input: "(nat 10)", output: "(1 2 3 4 5 6 7 8 9 10)"},
 
 		{input: "(join (reverse (split \"Steve\" \"\")))", output: "evetS"},
 	}