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.
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). This can be abbreviated to "p->m".
Pascal, on the other hand, dereferences with a postfixed "^", so that
would be "p^.m".
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