Implement multiplication

3 files changed, 89 insertions, 0 deletions

diff --git a/__tests__/dice.test.js b/__tests__/dice.test.js
index caba0a9..4e89031 100644
--- a/__tests__/dice.test.js
+++ b/__tests__/dice.test.js
@@ -4,6 +4,7 @@ const {
   d,
   add,
   subtract,
+  multiply,
   bonusAdd,
   bonusSubtract,
   negative,
@@ -316,6 +317,28 @@ describe('subtract', () => {
   })
 })
 
+describe('multiply', () => {
+  describe('1d6 * 3', () => {
+    const die = multiply(d(constant(1), constant(6)), constant(3))
+    testDie(die, {
+      diceCount: 1,
+      average: {
+        average: 10.5
+      },
+      variance: {
+        variance: 26.25
+      },
+      bounds: {
+        low: 3,
+        high: 18,
+        expectLow: true,
+        expectHigh: true
+      }
+    })
+  })
+})
+
+
 describe('bonusAdd', () => {
   describe('1d20+3', () => {
     const die = bonusAdd(d(constant(1), constant(20)), constant(3))
diff --git a/__tests__/lexer.test.js b/__tests__/lexer.test.js
index b51c0f9..db7ab50 100644
--- a/__tests__/lexer.test.js
+++ b/__tests__/lexer.test.js
@@ -97,6 +97,30 @@ describe('lex', () => {
     })
   })
 
+  describe('lexes multiplication', () => {
+    it('1d6 * 1d4', () => {
+      expect(lex('1d6 * 1d4')).toEqual([
+        { type: 'constant', value: 1 },
+        { type: 'd' },
+        { type: 'constant', value: 6 },
+        { type: 'bigTimes' },
+        { type: 'constant', value: 1 },
+        { type: 'd' },
+        { type: 'constant', value: 4 }
+      ])
+    })
+
+    it('2d17 * 4', () => {
+      expect(lex('2d17 * 4')).toEqual([
+        { type: 'constant', value: 2 },
+        { type: 'd' },
+        { type: 'constant', value: 17 },
+        { type: 'bigTimes' },
+        { type: 'constant', value: 4 }
+      ])
+    })
+  })
+
   describe('lexes parentheses', () => {
     it('(1d6)d6', () => {
       expect(lex('(1d6)d6')).toEqual([
diff --git a/__tests__/parser.test.js b/__tests__/parser.test.js
index 6e575b6..5d4288d 100644
--- a/__tests__/parser.test.js
+++ b/__tests__/parser.test.js
@@ -97,6 +97,22 @@ describe('parse', () => {
     })
   })
 
+  it('parses dice multiplication', () => {
+    expect(parse('1d6 * 2d8')).toEqual({
+      type: 'multiply',
+      left: {
+        type: 'd',
+        left: { type: 'constant', value: 1 },
+        right: { type: 'constant', value: 6 }
+      },
+      right: {
+        type: 'd',
+        left: { type: 'constant', value: 2 },
+        right: { type: 'constant', value: 8 }
+      }
+    })
+  })
+
   it('parses additive bonuses', () => {
     expect(parse('3d4+1')).toEqual({
       type: 'bonusAdd',
@@ -282,4 +298,30 @@ describe('parse', () => {
       })
     })
   })
+
+  describe('order of operations', () => {
+    test('2 * 3 + 4', () => {
+      expect(parse('2 * 3 + 4')).toEqual({
+        type: 'add',
+        left: {
+          type: 'multiply',
+          left: { type: 'constant', value: 2 },
+          right: { type: 'constant', value: 3 },
+        },
+        right: { type: 'constant', value: 4 },
+      })
+    })
+
+    test('2 + 3 * 4', () => {
+      expect(parse('2 + 3 * 4')).toEqual({
+        type: 'add',
+        left: { type: 'constant', value: 2 },
+        right: {
+          type: 'multiply',
+          left: { type: 'constant', value: 3 },
+          right: { type: 'constant', value: 4 },
+        }
+      })
+    })
+  })
 })