On 2015-12-04 01:56, Chris Angelico wrote:
On Fri, Dec 4, 2015 at 12:25 PM, Steven D'Aprano <st...@pearwood.info> wrote:
I don't see any good reason for maintaining that there's just one
syntax, "display", which comes in two forms: a comma-separated set of
values, or a for-loop. The only thing they have in common (syntax-wise)
is that they both use [ ] as delimiters. They look different, they
behave differently, and only one matches what the list actually displays
as. Why use one term for what is clearly two distinct (if related)
syntaxes?
You come across something syntactic that begins by opening a square
bracket, and you know that its semantics are: "construct a new list".
That's what's common here.
What goes *inside* those brackets can be one of two things:
1) A (possibly empty) comma-separated sequence of expressions
2) One or more nested 'for' loops, possibly guarded by 'if's, and a
single expression
So we have two subforms of the same basic syntax. The first one
corresponds better to the output format, in the same way that a string
literal might correspond to its repr under specific circumstances.
Neither is a literal. Neither is a call to a constructor function
(contrast "list()" or "list.__new__(list)", which do call a
constructor). So what is this shared syntax? Whatever word is used,
it's going to be a bit wrong. I'd be happy with either "constructor"
or "display", myself.
The problem with "constructor" is that it's already used for the "__new__"
class method.
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