That's true, but JoshTriplett has a reasonable point. In point of fact, we are discussing custom value types like int32 and uint32, as well as compound value types like immutable records, for the future of ECMAScript:
But standardization takes time, and we wanted to get asm.js working now.
In the future if ECMAScript gains these other features we'll happily incorporate whichever ones make sense. For example, if having more straightforward syntax can help decrease code size that's a clear win. (Though gzipping source tends to mask a multitude of sins.)
http://wiki.ecmascript.org/doku.php?id=strawman:value_object...
But standardization takes time, and we wanted to get asm.js working now.
In the future if ECMAScript gains these other features we'll happily incorporate whichever ones make sense. For example, if having more straightforward syntax can help decrease code size that's a clear win. (Though gzipping source tends to mask a multitude of sins.)