The D Programming Language: cases (fallthrough)

[Richard Harter]

In article <12159 at brl-adm.ARPA> PEPRBV%CFAAMP.BITNET at husc6.harvard.EDU (Bob Babcock) writes:

>I don't understand.  First you give a perfectly reasonable example of
>the use of goto (which would be awkward to code otherwise), and then
>you propose eliminating goto from the language because you don't use
>it very often.  One of the reasons I like programming in C rather than
>(pre-77) Fortran is that you have the flow control constructs
>necessary to eliminate abusive use of goto's, but you still have
>goto available for the occasional place where it best expresses
>what you want to do.

My apologies for muddying the waters.  Yes, there are rare occasions where
a goto lets you build by hand a construct that is not available in the
language.  Most of these instances reflect deficiencies in the language.
In the example I cited the deficiencies are:

(a)	C has two escape statements, break and return.  'return' escapes
from the outermost containing block (the function).  'break' is a little
ambiguous.  By analogy one would expect it to escape from the innermost
containing block.  Actually, of course, it escapes from loops and switch
control structures.  C would be improved if it had better escape constructs.

(b)	C has no provision for epilogs -- an epilog being a block of code
executed after an escape.  I don't quite see how one puts epilogs in C
in any natural fashion.

The question I was raising was whether the rare instances where a goto
is actually useful warrant retaining it in the language.  You and I, of
course, will use them wisely and only when warranted.  But I could do
without them in C.  The times that I would have to get around not having
them available are few compared to other awkwardnesses in the language.

Incidentally, the objection I have to older Fortran is not so much
the abusive use of goto's (a complaint I will leave to theoreticians)
but is their awkwardness -- expressing any kind of complicated logic
in Fortran 66 is rather like solving a chinese box puzzle.
-- 

In the fields of Hell where the grass grows high
Are the graves of dreams allowed to die.
	Richard Harter, SMDS  Inc.