On 18/03/2022 17:49, Paul Dragoonis wrote:
Writing code in strings is a DX nightmare
Can you expand a bit on what you mean by that? It seems to be common to
assert the opposite, that string interpolation is much more convenient
than the alternatives.
Looking around, it seems nearly all currently-popular languages include
some form of interpolation.
Notable languages which don't currently support it at all are Java and
Go. Rust doesn't have a generic syntax, but some built-in macros support
variable-only interpolation:
https://blog.rust-lang.org/2022/01/13/Rust-1.58.0.html#captured-identifiers-in-format-strings
Perl, from which PHP has largely inherited its string syntax, is
actually more restrictive than most. Arbitrary expressions are just
about possible with a bit of hackery, but not really encouraged:
https://perldoc.perl.org/perlfaq4#How-do-I-expand-function-calls-in-a-string%3F
All the other languages I looked at have support for full expressions in
their interpolation forms:
* C# - $"x + y = {x + y}" -
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/interpolated
* Dart - 'x + y = ${x + y}' -
https://api.dart.dev/stable/2.16.1/dart-core/String-class.html
* JavaScript - `x + y = ${x + y}` -
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals
* Kotlin - "x + y = ${x + y}" -
https://kotlinlang.org/docs/basic-types.html#string-templates
* Python - f'x + y = {x + y}' - https://peps.python.org/pep-0498/
* Raku (Perl6) - "\$x + \$y = { $x + $y }" -
https://docs.raku.org/language/quoting.html#Interpolation:_qq
* Ruby - "x + y = #{x + y}" -
http://ruby-for-beginners.rubymonstas.org/bonus/string_interpolation.html
* Scala - s"x + y = ${$x + $y}" -
https://docs.scala-lang.org/overviews/core/string-interpolation.html
* Swift - "x + y = \(x + y)" -
https://docs.swift.org/swift-book/LanguageGuide/StringsAndCharacters.html#ID292
Interestingly, a few languages have forms that combine arbitrary
expression interpolation with printf-style modifiers. For instance, to
format a float x to 3 decimal places, aligned right to width 10:
* C# - $"{x,10:F3}"
* Python - f"{x:10.3}"
* Scala - f"$x%10.3f"
It might be interesting to explore this for PHP, e.g. "{$:$x:10.3f}". If
we're not sure we want it yet, we could leave the option open by making
anything of the form "{$:expression:format}" a syntax error.
Using a second colon would make ternary expressions slightly awkward; C#
handles this by requiring them to be parenthesised, so "{$:( $test ? $x
: $y )}" would be valid but "{$:$test ? $x : $y}" would not; we could
use some other delimiter, but they'd probably all need something similar.
PS: Reminder to all that convention on this list is to reply below not
above quoted text.
--
Rowan Tommins
[IMSoP]
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