From 08c645a70f26bd9d6a529aa35365e376d405ea2a Mon Sep 17 00:00:00 2001
From: Leon Mika <lmika@lmika.org>
Date: Sat, 7 Sep 2024 09:14:21 +1000
Subject: [PATCH] issue-1: added and, or, and not

---
 ucl/builtins.go          | 34 ++++++++++++++++++++++++++++
 ucl/inst.go              |  4 ++++
 ucl/testbuiltins_test.go | 49 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)

diff --git a/ucl/builtins.go b/ucl/builtins.go
index b0e1035..f36842e 100644
--- a/ucl/builtins.go
+++ b/ucl/builtins.go
@@ -264,6 +264,40 @@ func geBuiltin(ctx context.Context, args invocationArgs) (object, error) {
 	return boolObject(isGreater || objectsEqual(args.args[0], args.args[1])), nil
 }
 
+func andBuiltin(ctx context.Context, args invocationArgs) (object, error) {
+	if err := args.expectArgn(2); err != nil {
+		return nil, err
+	}
+
+	for _, a := range args.args {
+		if a == nil || !a.Truthy() {
+			return boolObject(false), nil
+		}
+	}
+	return args.args[len(args.args)-1], nil
+}
+
+func orBuiltin(ctx context.Context, args invocationArgs) (object, error) {
+	if err := args.expectArgn(2); err != nil {
+		return nil, err
+	}
+
+	for _, a := range args.args {
+		if a != nil && a.Truthy() {
+			return a, nil
+		}
+	}
+	return boolObject(false), nil
+}
+
+func notBuiltin(ctx context.Context, args invocationArgs) (object, error) {
+	if err := args.expectArgn(1); err != nil {
+		return nil, err
+	}
+
+	return boolObject(!args.args[0].Truthy()), nil
+}
+
 var errObjectsNotEqual = errors.New("objects not equal")
 
 func objectsEqual(l, r object) bool {
diff --git a/ucl/inst.go b/ucl/inst.go
index 9ef7585..c19f9cd 100644
--- a/ucl/inst.go
+++ b/ucl/inst.go
@@ -76,6 +76,10 @@ func New(opts ...InstOption) *Inst {
 	rootEC.addCmd("div", invokableFunc(divBuiltin))
 	rootEC.addCmd("mod", invokableFunc(modBuiltin))
 
+	rootEC.addCmd("and", invokableFunc(andBuiltin))
+	rootEC.addCmd("or", invokableFunc(orBuiltin))
+	rootEC.addCmd("not", invokableFunc(notBuiltin))
+
 	rootEC.addCmd("cat", invokableFunc(concatBuiltin))
 	rootEC.addCmd("break", invokableFunc(breakBuiltin))
 	rootEC.addCmd("continue", invokableFunc(continueBuiltin))
diff --git a/ucl/testbuiltins_test.go b/ucl/testbuiltins_test.go
index 8acd925..8094824 100644
--- a/ucl/testbuiltins_test.go
+++ b/ucl/testbuiltins_test.go
@@ -1149,3 +1149,52 @@ func TestBuiltins_AddSubMupDivMod(t *testing.T) {
 		})
 	}
 }
+
+func TestBuiltins_AndOrNot(t *testing.T) {
+	tests := []struct {
+		desc    string
+		expr    string
+		want    any
+		wantErr bool
+	}{
+		{desc: "and 1", expr: `and $true $true`, want: true},
+		{desc: "and 2", expr: `and $false $true`, want: false},
+		{desc: "and 3", expr: `and $false $false`, want: false},
+		{desc: "or 1", expr: `or $true $true`, want: true},
+		{desc: "or 2", expr: `or $false $true`, want: true},
+		{desc: "or 3", expr: `or $false $false`, want: false},
+		{desc: "not 1", expr: `not $true`, want: false},
+		{desc: "not 2", expr: `not $false`, want: true},
+		{desc: "not 3", expr: `not $false $true`, want: true},
+
+		{desc: "short circuit and 1", expr: `and "hello" "world"`, want: "world"},
+		{desc: "short circuit and 2", expr: `and () "world"`, want: false},
+		{desc: "short circuit or 1", expr: `or "hello" "world"`, want: "hello"},
+		{desc: "short circuit or 2", expr: `or () "world"`, want: "world"},
+
+		{desc: "bad and 1", expr: `and "one"`, wantErr: true},
+		{desc: "bad and 2", expr: `and`, wantErr: true},
+		{desc: "bad or 1", expr: `or "one"`, wantErr: true},
+		{desc: "bad or 2", expr: `or`, wantErr: true},
+		{desc: "bad not 2", expr: `not`, wantErr: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			ctx := context.Background()
+			outW := bytes.NewBuffer(nil)
+
+			inst := New(WithOut(outW), WithTestBuiltin())
+			inst.SetVar("true", true)
+			inst.SetVar("false", false)
+
+			eqRes, err := inst.Eval(ctx, tt.expr)
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.want, eqRes)
+			}
+		})
+	}
+}