Exponential number notation (shellscape#36)

* Add failing tests for exponential number notation

* Add support for exponential number notation

* Fix exponential notation for numbers starting with a period

* Extract digit charCodes to constants

* Improve variable names

Author: lydell

lib/parser.js

@@ -382,7 +382,7 @@ module.exports = class Parser {
   splitWord () {
     let nextToken = this.nextToken,
       word = this.currToken[1],
-      rNumber = /^[\+\-]?((\d+(\.\d*)?)|(\.\d+))/,
+      rNumber = /^[\+\-]?((\d+(\.\d*)?)|(\.\d+))([eE][\+\-]?\d+)?/,
 
       // treat css-like groupings differently so they can be inspected,
       // but don't address them as anything but a word, but allow hex values

lib/tokenize.js

@@ -8,6 +8,7 @@ const singleQuote = '\''.charCodeAt(0);
 const doubleQuote = '"'.charCodeAt(0);
 const backslash = '\\'.charCodeAt(0);
 const slash = '/'.charCodeAt(0);
+const period = '.'.charCodeAt(0);
 const comma = ','.charCodeAt(0);
 const colon = ':'.charCodeAt(0);
 const asterisk = '*'.charCodeAt(0);
@@ -20,6 +21,10 @@ const feed = '\f'.charCodeAt(0);
 const tab = '\t'.charCodeAt(0);
 const cr = '\r'.charCodeAt(0);
 const at = '@'.charCodeAt(0);
+const lowerE = 'e'.charCodeAt(0);
+const upperE = 'E'.charCodeAt(0);
+const digit0 = '0'.charCodeAt(0);
+const digit9 = '9'.charCodeAt(0);
 const atEnd = /[ \n\t\r\{\(\)'"\\;,/]/g;
 const wordEnd = /[ \n\t\r\(\)\{\}\*:;@!&'"\+\|~>,\[\]\\]|\/(?=\*)/g;
 const wordEndNum = /[ \n\t\r\(\)\{\}\*:;@!&'"\-\+\|~>,\[\]\\]|\//g;
@@ -299,7 +304,7 @@ module.exports = function tokenize (input, options) {
 
           // we're dealing with a word that starts with a number
           // those get treated differently
-          if (code >= 48 && code <= 57) {
+          if (code >= digit0 && code <= digit9) {
             regex = wordEndNum;
           }
 
@@ -313,6 +318,29 @@ module.exports = function tokenize (input, options) {
             next = regex.lastIndex - 2;
           }
 
+          // Exponential number notation with minus or plus: 1e-10, 1e+10
+          if (regex === wordEndNum || code === period) {
+            let ncode1 = css.charCodeAt(next),
+              ncode2 = css.charCodeAt(next + 1),
+              ncode3 = css.charCodeAt(next + 2);
+
+            if (
+              (ncode1 === lowerE || ncode1 === upperE) &&
+              (ncode2 === minus || ncode2 === plus) &&
+              (ncode3 >= digit0 && ncode3 <= digit9)
+            ) {
+              wordEndNum.lastIndex = next + 2;
+              wordEndNum.test(css);
+
+              if (wordEndNum.lastIndex === 0) {
+                next = css.length - 1;
+              }
+              else {
+                next = wordEndNum.lastIndex - 2;
+              }
+            }
+          }
+
           tokens.push(['word', css.slice(pos, next + 1),
             line, pos  - offset,
             line, next - offset,

test/number.js

@@ -98,6 +98,50 @@ describe('Parser → Number', () => {
     {
       test: '-16px -1px -1px -16px',
       expected: { value: '-16', unit: 'px', length: 4 }
+    },
+    {
+      test: '1e10',
+      expected: { value: '1e10', unit: '', length: 1 }
+    },
+    {
+      test: '1E10',
+      expected: { value: '1E10', unit: '', length: 1 }
+    },
+    {
+      test: '1e-10',
+      expected: { value: '1e-10', unit: '', length: 1 }
+    },
+    {
+      test: '1E-10',
+      expected: { value: '1E-10', unit: '', length: 1 }
+    },
+    {
+      test: '1e+10',
+      expected: { value: '1e+10', unit: '', length: 1 }
+    },
+    {
+      test: '1E+10',
+      expected: { value: '1E+10', unit: '', length: 1 }
+    },
+    {
+      test: '1e -10',
+      expected: { value: '-10', unit: '', length: 2 }
+    },
+    {
+      test: '1e',
+      expected: { value: '1', unit: 'e', length: 1 }
+    },
+    {
+      test: '-.567800E-0012780em',
+      expected: { value: '-.567800E-0012780', unit: 'em', length: 1 }
+    },
+    {
+      test: '.1E-10',
+      expected: { value: '.1E-10', unit: '', length: 1 }
+    },
+    {
+      test: '.1E+10',
+      expected: { value: '.1E+10', unit: '', length: 1 }
     }
   ];
 
@@ -174,6 +218,10 @@ describe('Parser → Number : Loose', () => {
     {
       test: '-16px -1px -1px 16px',
       expected: { value: '16', unit: 'px', length: 6 }
+    },
+    {
+      test: '5e+5',
+      expected: { value: '5e+5', unit: '', length: 1 }
     }
   ];
 

test/tokenize.js

@@ -15,7 +15,8 @@ describe('Tokenize', () => {
     { value: 'Bond\\ 007', expectedLength: 4 },
     { value: ' \\"word\\\'"\\ \\\t ', expectedLength: 7 },
     { value: 'bar(baz(black, 10%), 10%)', expectedLength: 13 },
-    { value: '-16px -1px -1px -16px', expectedLength: 11 }
+    { value: '-16px -1px -1px -16px', expectedLength: 11 },
+    { value: '.56E-0123', expectedLength: 1 }
   ];
 
   fixtures.forEach((fixture) => {