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. http://www-formal.stanford.edu/jmc/recursive/node2.html (the paper famously titled "Part I" without any Part II, unless I mistake much.) It got implemented as (cond (c1 e1) (c2 e2) ... (cn en)), and I'm not sure when (if c e1 e2) became available as an alternative conditional expression in the Lisp family (called LISP back then, just like Python was called PYTHON if it was called at all). I think Algol 60 had something like "if c then e1 else e2" as an expression, also due to McCarthy. Keywords probably bold-faced. I'm perfectly happy with Python's conditional expression syntax, which cascades surprisingly well. I'm unhappy with C's, not sure why. I think I would like McCarthy's original syntax. (Dijkstra had a similar syntax but the clauses were not ordered. Each guard had to stand alone and any one branch with a true guard could be chosen. But that may have been a statement only.) -- https://mail.python.org/mailman/listinfo/python-list
