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> It's a pet peeve of mine that C people seem to think that 0 isn't a number. Or that 0 (or -1) mean infinity. It's not just C people :D - Zero may or may not

> It's a pet peeve of mine that C people seem to think that 0 isn't a number. Or that 0 (or -1) mean infinity. It's not just C people :D - Zero may or may not be a natural number depending on who you ask, and negative numbers definitely are not. And since in low-level programming, which is kind of C's kingdom, every bit might count and you'd rather use that useless sign bit for something else. -1 being particularly liked by compilers because it is "all bits set" in the dominant two's complement sign encoding, which sometimes allows optimization tricks. > I guess it's mostly a consequence of C having such poor support for data types. Technically nothing prevents anyone from returning a small two fields structure - one for a tag and one for the value - to have "tagged unions" or "optional types" almost like your favorite language. But in the eyes of a low-level C programmer, that's one field too much (omg that doesn't fit in a register, you will be held responsible for global warming if you publish this etc.). So, it's not that we think that anything non-positive is not a "true number", it's more like we've been using these conventions sometimes since assembly programming days (OR AX,AX to test if register AX is zero in old x86 assembly, because the OR instruction sets the CPU's Z flag) in order to get maximum performance.

eru 3y ago
You are right about cramming things into bits. But it often makes code more complicated. Eg if you have two operations you do one after another and they have time-outs of t1 and t2, then normally, you know that after t1+t2, either both will have succeeded, or they will have failed. But that breaks down with the 'C-conventions' when either t1 or t2 equals 0. Thus you need extra logic to deal with these. As an aside: OCaml uses tagged pointers to cram more information into machine words. That's an implementation technique, and (mostly) hidden from users of the language. (Apart from integers having 63 bits, instead of 64 bits size by default.) So that's an example where the language is 'clean', but the implementation is still efficient and uses all the low level tricks. And my pet peeve is more that many people always do this trickery, even when not every bit counts. > It's not just C people :D - Zero may or may not be a natural number depending on who you ask, and negative numbers definitely are not. Yes, but I never mentioned any restriction to Natural numbers. Btw, in the context of computers 0 is definitely a number that comes natural, even if it's not a Natural number by some people's definition.

eru 3y ago

You are right about cramming things into bits. But it often makes code more complicated. Eg if you have two operations you do one after another and they have time-outs of t1 and t2, then normally, you know that after t1+t2, either both will have succeeded, or they will have failed. But that breaks down with the 'C-conventions' when either t1 or t2 equals 0. Thus you need extra logic to deal with these. As an aside: OCaml uses tagged pointers to cram more information into machine words. That's an implementation technique, and (mostly) hidden from users of the language. (Apart from integers having 63 bits, instead of 64 bits size by default.) So that's an example where the language is 'clean', but the implementation is still efficient and uses all the low level tricks. And my pet peeve is more that many people always do this trickery, even when not every bit counts. > It's not just C people :D - Zero may or may not be a natural number depending on who you ask, and negative numbers definitely are not. Yes, but I never mentioned any restriction to Natural numbers. Btw, in the context of computers 0 is definitely a number that comes natural, even if it's not a Natural number by some people's definition.