Re: How to type braces for computed gotos

Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:


> I guess this compiler implements the labels-as-values extension of GNU
> C (aka "computed goto", but see the Fortran note below). The type of
> a label is always void *; static typing fans might prefer a separate
> label type (or a whole type system for labels), but I guess that the
> intersection between static typing fans and the users of this
> extension is very small. I have used labels-as-values extensively and
> I have not produced errors stemming from confusion between labels and
> other occurences of void *.
>
> BTW, in Fortran this feature is called "assigned goto", and it uses
> integer variables (i.e., not a special type, either) for storing the
> labels (and therefore needs a separate syntax "assign 50 to l" instead
> of just writing "l=50"). Fortran also has a feature called "computed
> goto", but that is closer to a C switch than a GNU C "goto *".


Not quite the rough equivalent of a C switch statement is the Fortran 90
SELECT CASE. A Fortran computed GO TO, as with an assigned GO TO, does
not have a syntactic block associated with it, and can be set up to go
to any label within the current program or sub-program.

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