DIP 1027---String Interpolation---Community Review Round 1

mipri mipri at minimaltype.com
Tue Dec 17 17:31:20 UTC 2019

On Tuesday, 17 December 2019 at 17:13:50 UTC, Patrick Schluter 
> Which was my point. An interpolated string cannot be stored in 
> a simple string as some people requested in the thread before 
> (not you). It is only feasible if the istring is evaluated at 
> runtime with an interpreter who knows the current values of the 
> variables used. Interpreted languages like python, perl, 
> javascript etc. might get away with it but compiled languages 
> have to transform it in its code representation.

These languages also don't store "interpolated strings" in
variables; they store strings in variables, and any string
interpolation happens at the literal.

Crystal (compiled language with a real type system, etc.):

   apple = 0
   my_is = "apple=#{apple}"
   apple = 36
   puts my_is

Ruby (interpreted scripting language):

   apple = 0
   my_is = "apple=#{apple}"
   apple = 36
   puts my_is

Both output "apple=0". I can't recall a case where you'd get
"apple=36". You'd have to deliberately delay evaluation of the

But I don't think anyone's asked for any other behavior than
this. What's wanted is for

   int apple;
   string my_is = i"apple=$apple";
   apple = 36;

to output "apple=36" rather than result in a compile-time
error because i"..." doesn't evaluate to a string.

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