Computed gotos on Reddit

[bearophile]

A discussion appeared few days ago on Reddit, about computed 
gotos:

http://www.reddit.com/r/programming/comments/wld04/eli_benderskys_website_computed_goto_for/

http://eli.thegreenplace.net/2012/07/12/computed-goto-for-efficient-dispatch-tables/

Computed gotos are useful to write interpreters. Interpreters are 
a niche but important purpose of system languages like D. 
Computed gotos are also useful to implement certain finite state 
machines (like some used in computational biology).

The GCC back-end supports computed gotos very well, and recent 
versions of LLVM support them decently (but not perfectly). This 
means implementing those gotos in LDC2 and GDC is probably not 
too much hard. DMD back-end probably don't support them (and who 
knows how much work it takes to implement that).

So maybe someday people will add a nonstandard extension to D, 
for GDC and/or LDC to support computed gotos. I hope they will 
use the same syntax, but generally nonstandard extension are a 
portability pain, and some people (purists, language lawyers, 
etc) seem to hate them.

So I have suggested to define a standard syntax for computed 
gotos in D, so LDC and GDC will avoid inventing a different 
syntax, so only DMD is the nonsupporting compiler.

Bye,
bearophile