The D Programming Language (was: Still more new operators)

[Sun ECD Software]

In article <11702 at brl-adm.ARPA> dsill at NSWC-OAS.arpa (Dave Sill) writes:
>>Some years ago I invented the hypothetical notation "e1 ,, e2", which would be
>>like the comma operator in that it evaluates its left operand before its
>>right operand, but (unlike comma) the result would be the value of the left
>>operand.  Look what this buys us:
>>	a,, a=b		/* displacement operator, like a :=:= b */
>>	a=(b,, b=a)	/* a simple swap */
>>	x,, ++x		/* same as x++; but generalizable */
>>	free(stack,, stack=stack->next)	/* pop stack */
>>	stack->value,, pop(stack)	/* pop and return stacked value */
>
>I like it.  Nice and general, fills a gap missing in C.  It's not C,
>but it could be D (it *should* be D, not P (pee?)).

Actually, the last project course at the late Wang Institute developed
a compiler and editor for the D language called Turbo-D.  The D language
we used was taken from Dijkstra's guarded command language in his book
"A Discipline of Programming."  For the simple swap you have shown, the
D syntax seemed to be much cleaner:
        a,b := b,a

The language had some other features, including non-determinate selection
of guards for loops and conditional statements.  The project was fun, the
language was useful, and the compiler was fast.



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