MRAB <pyt...@mrabarnett.plus.com> writes: > On 2016-08-17 18:19, Jussi Piitulainen wrote: >> MRAB writes: >> >>> On 2016-08-17 12:24, Jussi Piitulainen wrote: >>>> BartC writes: >>>> >>>>> On 17/08/2016 07:39, Steven D'Aprano wrote: >>>>>> Rather than ask why Python uses `trueval if cond else falseval`, you >>>>>> should ask why C uses `cond ? trueval : falseval`. Is that documented >>>>>> anywhere? >>>>> >>>>> I'm not fond of C's a ? b : c but the principle is sound. I generally >>>> >>>> [- -] >>>> >>>>> Anyway a?b:c was existing practice. At least the order of a,b,c could >>>>> have been retained if not the exact syntax. >>>> >>>> The original was (c1 -> e1, c2 -> e2, ..., cn -> en) in John >>>> McCarthy's 1960 paper on symbolic expressions, with an actual arrow >>>> glyph in place of hyphen-greater-than. >>>> >>> [snip] >>> >>> BCPL, the ancestor of C, had: >>> >>> a -> b, c >> >> Nice. Add a redundant pair of parentheses and it's the same. (When used >> as an expression, a final else-branch is mandatory-ish.) >> >> But C uses -> for something else, I think. And other languages use it >> for lambda expressions (succesfully, I think, but then they don't have >> it available for this purpose). >> > C uses "->" for dereferencing a pointer to the member of a struct.
Slightly better wording: it uses -> to access a struct member via a pointer to the struct. > If "p" points to a struct (record), then "*p" is that struct, and if > that struct has a member (field) "m", then that member can be accessed > by "(*p)->m" (the parens are necessary because of the operator > precedence). I think you meant (*p).m here because you go on to correct say that -> offers a shorthand for this rather messy access: > This can be abbreviated to "p->m". > > Pascal, on the other hand, dereferences with a postfixed "^", so that > would be "p^.m". > -- Ben. -- https://mail.python.org/mailman/listinfo/python-list
