feat: tenery operator

src/grammar.js

@@ -63,6 +63,17 @@ class BinOP extends AST {
 	}
 }
 
+class TeneryOP extends AST {
+	constructor(exp, a, b) {
+		super();
+		Object.defineProperty(this, 'value', {
+			get: () => {
+				return exp.value ? a.value : b.value;
+			}
+		});
+	}
+}
+
 class FCall extends AST {
 	constructor(f, context, args) {
 		super();
@@ -170,6 +181,15 @@ export const grammar = create({
 			}
 		},
 		infix: {
+			'?': {
+				precedence: 20,
+				led(grammar, left) {
+					const e1 = grammar.expression(0);
+					grammar.advance(':');
+					const e2 = grammar.expression(0);
+					return new TeneryOP(left, e1, e2);
+				}
+			},
 			'.': {
 				precedence: 1,
 				combine: (left, right) => new ObjectAccess(left, right)
@@ -178,6 +198,7 @@ export const grammar = create({
 				precedence: 1,
 				combine: (left, right) => new ArrayAccess(left, right)
 			},
+			':': {},
 			']': {},
 			',': {},
 			')': {},

tests/simple_test.js

@@ -95,6 +95,19 @@ describe('expander', () => {
     });
   });
 
+  describe('tenery expression', () => {
+    it('true 1st.', () => expand("${2 > 1 ? 22 : 11}").then(r => assert.equal(r, 22)));
+    it('false 2nd.', () => expand("${2 < 1 ? 22 : 11}").then(r => assert.equal(r, 11)));
+
+    describe('combined', () => {
+      it('false 2nd.', () => expand("${2 < 1 ? 22+1 : 11+1}").then(r => assert.equal(r, 12)));
+      it('true 2nd.', () => expand("${2*0 < 1 ? 22+1 : 11+1}").then(r => assert.equal(r, 23)));
+      it('true 2nd. with function call', () => expand("${'a'=='b' ? 22+1 : substring('abc',1,2)}").then(r =>
+        assert.equal(r,
+          'b')));
+    });
+  });
+
   describe('functions', () => {
     it('unknown function', () => expand("${thisFunctionIsUnknown()}")
       .then(e => assert.equal(e, {}))