4 ms·

Are there any other examples of a programming language adding a type system after the fact?

dartos 3y ago
Elixir (and erlang) already has a type system, it’s just dynamic. Python and typescript both added stricter typing to their respective languages
- krainboltgreene 3y ago
  I don't think it's actually fair to say Elixir has a type system. There are expressions that are specially handled at the compiler level, but are mostly ignored unless you invoke another separate system. It's effectively comments that have syntax.
  - h0l0cube 3y ago
    It has a gradual type 'system', along with a means of type checking (via Dialyzer) at compile time. However the type checking isn't enforced at compile time, and it has the possibility for some false negatives (though it isn't so bad in experience).
    - krainboltgreene 3y ago
      Okay then by that measure comments with details about input and output are also a type system, an even easier one since there's generally only one syntax rule!
      - h0l0cube 3y ago
        What is code but interpreted text? If the comments are interpretable and enforced by a logical system, then they become instruction.
  - dartos 3y ago
    Functions can have pattern matching and guards which act as type safety measures, granted they are runtime and not as robust as, say, rust’s type system
  - dartos 3y ago
    Elixir has a clear concept of a “type” and can’t just change one type of data to another Willy nilly. Sounds like a type system to me. It’s even stricter than JavaScript, as it doesn’t silently try to coerce everything into a string
    - krainboltgreene 3y ago
      Yes but until you run another program the type is just data that gets thrown away. It is effectively just a more syntactically strict comment.
      - weatherlight 3y ago
        It is a Strongly Typed language (and always has been), It's just Dynamically Typed.
      - dartos 3y ago
        That’s just not true. Look at function guards
- abrookewood 3y ago
  Yes, I should have specified a Static type system
tiffanyh 3y ago
PHP
wutwutwat 3y ago
Not part of the official language spec, but Ruby has Sorbet, from a company who employs Ruby core contributors and helped with the recently released JIT additions to the language, among countless other contributions over the last couple decades. https://sorbet.org/ https://sorbet.org/
pohuing 3y ago
Dart went from a full dynamic system to a statically verified traditional system with null safety.
KevinMS 3y ago
typescript?
- abrookewood 3y ago
  Kinda ... it was built with types from the start, though I guess you could argue Typescript = Javascript + Types
weatherlight 3y ago
I presume you mean migrate from dynamic to static. check out Dart.

Elixir (and erlang) already has a type system, it’s just dynamic. Python and typescript both added stricter typing to their respective languages

krainboltgreene 3y ago
I don't think it's actually fair to say Elixir has a type system. There are expressions that are specially handled at the compiler level, but are mostly ignored unless you invoke another separate system. It's effectively comments that have syntax.
- h0l0cube 3y ago
  It has a gradual type 'system', along with a means of type checking (via Dialyzer) at compile time. However the type checking isn't enforced at compile time, and it has the possibility for some false negatives (though it isn't so bad in experience).
  - krainboltgreene 3y ago
    Okay then by that measure comments with details about input and output are also a type system, an even easier one since there's generally only one syntax rule!
    - h0l0cube 3y ago
      What is code but interpreted text? If the comments are interpretable and enforced by a logical system, then they become instruction.
- dartos 3y ago
  Functions can have pattern matching and guards which act as type safety measures, granted they are runtime and not as robust as, say, rust’s type system
- dartos 3y ago
  Elixir has a clear concept of a “type” and can’t just change one type of data to another Willy nilly. Sounds like a type system to me. It’s even stricter than JavaScript, as it doesn’t silently try to coerce everything into a string
  - krainboltgreene 3y ago
    Yes but until you run another program the type is just data that gets thrown away. It is effectively just a more syntactically strict comment.
    - weatherlight 3y ago
      It is a Strongly Typed language (and always has been), It's just Dynamically Typed.
    - dartos 3y ago
      That’s just not true. Look at function guards
abrookewood 3y ago
Yes, I should have specified a Static type system

tiffanyh 3y ago

PHP

wutwutwat 3y ago

Not part of the official language spec, but Ruby has Sorbet, from a company who employs Ruby core contributors and helped with the recently released JIT additions to the language, among countless other contributions over the last couple decades. https://sorbet.org/ https://sorbet.org/

pohuing 3y ago

Dart went from a full dynamic system to a statically verified traditional system with null safety.

KevinMS 3y ago

typescript?

abrookewood 3y ago
Kinda ... it was built with types from the start, though I guess you could argue Typescript = Javascript + Types

weatherlight 3y ago

I presume you mean migrate from dynamic to static. check out Dart.