gistfile1.js

var wsp = '(\\u0020|\\u0009|\\u000D|\\u000A)';
var digit = '\\d';
var digit_sequence = '(' + digit + '+' + ')';
var sign = '[-+]';
var exponent = '[eE]' + sign + '?' + digit_sequence;

var fractional_constant = 
    '(' + 
      digit_sequence + '?' + '\\.' + digit_sequence + 
      '|' +
      digit_sequence + '\\.' +
    ')';

var floating_point_constant = 
    '(' + 
      fractional_constant + exponent + '?' + 
      '|' + 
      digit_sequence + exponent + 
    ')';

var integer_constant = digit_sequence;
var comma = ',';

var comma_wsp = 
    '(' + 
      '(' + wsp + '+' + comma + '?' + wsp + '*' + ')' + 
      '|' + 
      '(' + comma + wsp + '*' + ')' + 
    ')';

var number = 
    '(' + 
      sign + '?' + integer_constant + 
      '|' + 
      sign + '?' + floating_point_constant + 
    ')';

new RegExp('^'+number+'$').test('5e'); // matches (but should not match)

/*
list-of-points:
    wsp* coordinate-pairs? wsp*
coordinate-pairs:
    coordinate-pair
    | coordinate-pair comma-wsp coordinate-pairs
coordinate-pair:
    coordinate comma-wsp coordinate
coordinate:
    number
number:
    sign? integer-constant
    | sign? floating-point-constant
comma-wsp:
    (wsp+ comma? wsp*) | (comma wsp*)
comma:
    ","
integer-constant:
    digit-sequence
floating-point-constant:
    fractional-constant exponent?
    | digit-sequence exponent
fractional-constant:
    digit-sequence? "." digit-sequence
    | digit-sequence "."
exponent:
    ( "e" | "E" ) sign? digit-sequence
sign:
    "+" | "-"
digit-sequence:
    digit
    | digit digit-sequence
digit:
    "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
wsp:
    (#x20 | #x9 | #xD | #xA)+
*/