[TUHS] Fwd: [Simh] An abandoned piece of K&R C
Lawrence Stewart
stewart at serissa.com
Fri Nov 3 22:53:40 AEST 2017
This caught my attention. Did early C really have min and max? Were they used for anything? In those days I was a BCPL user, which IIRC, did not have such things.
-Larry
> Begin forwarded message:
>
> From: Leo Broukhis <leob at mailcom.com>
> Subject: [Simh] An abandoned piece of K&R C
> Date: 2017, November 3 at 1:14:42 AM EDT
> To: "simh at trailing-edge.com" <simh at trailing-edge.com>
>
> https://retrocomputing.stackexchange.com/q/4965/4025 <https://retrocomputing.stackexchange.com/q/4965/4025>
>
> In the UNIX V7 version of the C language, there were the /\ (min) and the \/ (max) operators. In the source of the scanner part of the compiler,
>
> case BSLASH:
> if (subseq('/', 0, 1))
> return(MAX);
> goto unkn;
>
> case DIVIDE:
> if (subseq('\\', 0, 1))
> return(MIN);
> ...
>
> However, attempting to use them reveals that the corresponding part in the code generator is missing. Trying to compile
>
> foo(a, b) { return a \/ b; }
>
> results in
>
> 1: No code table for op: \/
>
> The scanner piece survived in the copies of the compiler for various systems for several years. I tried to look for copies of the code generator table which would contain an implementation, but failed. Has anyone ever seen a working MIN/MAX operator in K&R C?
>
> Thanks,Leo
>
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