Re: Using C as a back end

Keith Thompson <kst@cts.com> wrote:
> Peter Gammie <peteg@cse.unsw.edu.au> writes:
> [...]
>> The biggest problem with compiling to C is its lack of
>> expressiveness; almost certainly you'll want to use gcc's extensions
>> (such as goto), unless your language is already close to C.


> Just to clarify, goto is part of the standard C language, not a gcc
> extension. gcc does provide computed gotos, though, which standard C
> lacks. (Whether this is a good thing is a can of worms I choose not
> to open.)


For many applications, indirect jumps (computed gotos) are essential.
gcc allows a program to load a label L into a void* pointer p via the
expression p=&&L. One can then goto L via the statement goto *p;
There are, however, ways to fake this sort of thing in Standard C/C++
by using a switch statement.


Tom Payne
[Once again, an indirect jump is, in Fortran-ese, an assigned goto.
Or if you speak Cobol, it's an ALTERed goto. -John]

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