Converting String to UnitValues?

Question

Hello,
how would i convert a string object to a UnitValue object?
Say i have a an editbox.text where the user entered the string "2 in".
How do i make it a unitvalue so i can convert it to another unit?
regards,
Stephan

Answer 1

And here is the resulting function that parses strings as Unitvalues and does unit conversions.
var str = Edittext.text; // user enters "10in" or "-1 pt" or anything
var unitval = parseUnitValue(str, "mm");
Edittext.text = unitval;
function parseUnitValue (s, baseUnit) {
// it's beautiful!
// converts a string, for instance "-10.1 yard" or "0,23 mm" or ".3 pt" to a unitvalue. And then returns this value converted to baseUnit
// for instance if s literally is "1 inch" or "1in" and baseUnit is "mm" the function will return 25.4
// returns zero if the string doesn't parse to a unitValue!
if (s == undefined || s == '') { s = 0 } // if string empty make Zero
var regex = /(\-*\d*[\.|,]?\d*\s*)(in|inch|inches|ft|foot|feet|yd|yard|yards|mi|mile|miles|mm|millime ter|millimeters|cm|centimeter|centimeters|m|meter|meters|km|kilometer|kilometers|pt|point| points|pc|pica|picas|ci|cicero|ciceros)?/gi;
var myMatch = s.match(regex);
try {
var stringIsValid = ( s ==myMatch[ 0 ] ); // compare the string to the regular expression matched string. If they are equal then the string fits the required form for a unitvalue.
catch( e ) {
var stringIsValid = false; // if the string is not valid, something in the string was bad. Perhaps it was "+-10in" or "mommy" or "10i". Its not suitable for a unitvalue.
if (stringIsValid) {
var sVal = s.replace(regex, RegExp.$1).split(",").join("."); // get the real value part of the string. Also convert comma to point;
var sUnit = s.replace(regex, RegExp.$2); // get the unit part of the string.
if (sUnit == undefined || sUnit == "") { sUnit = baseUnit; } // this is for the case when the string is a number only, like "0", or "10.2", We then assume the user wanted the baseunit.
else { // if String doesn't parse as a unitvalue, make Zero
alert("Unknown Unit. Try: \n in, inch, inches, ft, foot, feet, yd, yard, yards, mi, mile, miles, pt, point, points, pc, pica, picas, ci, cicero, ciceros, \n mm, millimeter, millimeters, cm, centimeter, centimeters, m, meter, meters, km, kilometer, kilometers :)");
var sVal = 0;
var sUnit = baseUnit;
var myUnitValue = new UnitValue(sVal, sUnit); // create a unitvalue object...
return myUnitValue.as(baseUnit); // ...but output its value only - converted to baseUnit