fixes #29; calc with leading operator within parens

Author: shellscape

lib/number.js

@@ -11,8 +11,6 @@ class NumberNode extends Node {
   }
 
   toString () {
-    // console.log('node >', 'toString:', this.value);
-
     return [
       this.raws.before,
       String(this.value),

lib/parser.js

@@ -146,7 +146,8 @@ module.exports = class Parser {
       if (!this.options.loose) {
         if (this.position > 0) {
           if (this.current.type === 'func' && this.current.value === 'calc') {
-            if (this.prevToken[0] !== 'space') {
+            // allow operators to be proceeded by spaces and opening parens
+            if (this.prevToken[0] !== 'space' && this.prevToken[0] !== '(') {
               this.error('Syntax Error', this.currToken);
             }
             // valid: calc(1 - +2)
@@ -155,8 +156,10 @@ module.exports = class Parser {
               this.error('Syntax Error', this.currToken);
             }
             // valid: calc(1 - +2)
+            // valid: calc(-0.5 + 2)
             // invalid: calc(1 -2)
-            else if (this.nextToken[0] === 'word' && this.current.last.type !== 'operator') {
+            else if (this.nextToken[0] === 'word' && this.current.last.type !== 'operator' &&
+                     this.current.last.value !== '(') {
               this.error('Syntax Error', this.currToken);
             }
           }

test/function.js

@@ -35,6 +35,17 @@ describe('Parser → Function', () => {
         { type: 'word', value: 'baz' }
       ]
     },
+    // not ready yet - #30
+    // {
+    //   it: 'should loosely parse url function with sub func',
+    //   test: 'url(var(foo))',
+    //   loose: true,
+    //   expected: [
+    //     { type: 'func', value: 'url' },
+    //     { type: 'paren', value: '(' },
+    //     { type: 'paren', value: ')' }
+    //   ]
+    // },
     {
       it: 'should parse url function',
       test: 'url( /gfx/img/bg.jpg )',
@@ -70,6 +81,21 @@ describe('Parser → Function', () => {
         { type: 'paren', value: ')' }
       ]
     },
+    {
+      it: 'should parse calc function with number and var #29',
+      test: 'calc(-0.5 * var(foo))',
+      expected: [
+        { type: 'func', value: 'calc' },
+        { type: 'paren', value: '(' },
+        { type: 'number', value: '-0.5', unit: '' },
+        { type: 'operator', value: '*' },
+        { type: 'func', value: 'var' },
+        { type: 'paren', value: '(' },
+        { type: 'word', value: 'foo' },
+        { type: 'paren', value: ')' },
+        { type: 'paren', value: ')' }
+      ]
+    },
     {
       it: 'should parse calc function with nutty numbers',
       test: 'calc(1px + -2vw - 4px)',
@@ -140,7 +166,7 @@ describe('Parser → Function', () => {
 
   fixtures.forEach((fixture) => {
     it(fixture.it, () => {
-      let ast = new Parser(fixture.test).parse(),
+      let ast = new Parser(fixture.test, { loose: fixture.loose }).parse(),
         index = 0;
 
       ast.first.walk((node) => {

test/number.js

@@ -11,6 +11,18 @@ describe('Parser → Number', () => {
       test: '.23rem',
       expected: { value: '.23', unit: 'rem', length: 1 }
     },
+    {
+      test: '0.5',
+      expected: { value: '0.5', unit: '', length: 1 }
+    },
+    {
+      test: '-0.5',
+      expected: { value: '-0.5', unit: '', length: 1 }
+    },
+    {
+      test: '-0.5 * 1',
+      expected: { value: '1', unit: '', length: 3 }
+    },
     {
       test: '.2.3rem',
       expected: { value: '.2', unit: '.3rem', length: 1 }