Discussion Thread: DIP 1036--Formatted String Tuple Literals--Community Review Round 1
Adam D. Ruppe
destructionator at gmail.com
Wed Sep 9 23:47:35 UTC 2020
On Wednesday, 9 September 2020 at 23:04:37 UTC, James Blachly
> Are there contemporary examples of other languages whose string
> interpolation is as complex as this proposals? I am really only
> automatic memory management and the *string is a string is a
difference that in D, we reuse existing normal function call
syntax just for this feature.
See the "Tagged templates" section here:
Notice that they call it a "template literal" rather than an
interpolated string since it is so much more than a string.
If you write
foo([ "", ", ", ", ", "" ], 5, 23);
I realize that's hard to read with all the quotes and commas...
but it is essentially a dynamically-typed equivalent to what this
DIP is talking about.
The first argument to foo is a string spec. In D, we represent it
array of strings. But it is fundamentally the same idea: it gives
the string pieces from around the placeholders and an entry
representing the inserted item.
Then, the interpolated items are passed as separate arguments
after the spec - just like we propose for D. The example on MDN
for this uses JS' `...values` syntax to put it into an array, in
D, we'd call that same thing `(Values...)(Values values)`, but
again it is the same thing, just JS uses their dynamic typing
whereas D uses a template.
default function. Above, I wrote foo`...`. Leave the foo part off
and it uses the default function instead - which is identical to
our proposed idup. JS can do this because they introduced a new
function call syntax to the language. And they can do that
because JS only has one kind of function call to begin with:
obj.foo(x) (where obj is optional and will default to null).
D, by contrast, has several kinds of function calls: traditional
foo(x), UFCS x.foo, and template foo!(x). Instead of inventing
three new kinds of magic function call syntax, we just reuse what
we already have. But, of course, that does have one small
downside: there's no way to insert a default function like
to just one case and forgetting about the others.
Instead we simply ask you to explicitly call the function you
want in all cases. I doubt most users will even find this
particular controversial after they try it in reality.
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