5 ms·

Only Lisps have a reader so I'm not sure the term REPL is accurate with other languages. Interactive console != REPL.

by cutler 5y ago

Zababa 5y ago
Could you expand on that? I've searched a bit but the Lisp read doesn't sound too different from what other languages do.
- simiones 5y ago
  Unlike most languages, Lisp defines how strings can be transformed to Lisp ASTs (s-expressions). In Scheme (which doesn't allow reader macros) this is a safe operation: you can read untrusted input without worry. By contrast, most other languages only have eval() - which takes a string and parses and executes it as code. In Lisp, eval() takes a Lisp list object and executes that.
  - draegtun 5y ago
    Ditto for Rebol & Red. For eg. >> code: load "foreach n [1 2 3 4] [print n * 2]" == [foreach n [1 2 3 4] [print n * 2] ] >> type? code == block! >> do code 2 4 6 8
- capableweb 5y ago
  This is probably the best blog post I've seen on the topic: https://vvvvalvalval.github.io/posts/what-makes-a-good-repl.html https://vvvvalvalval.github.io/posts/what-makes-a-good-repl.... > If you're not familiar with Clojure, you may be surprised that I describe the REPL as Clojure's most differentiating feature: after all, most industrial programming languages come with REPLs or 'shells' these days (including Python, Ruby, Javascript, PHP, Scala, Haskell, ...). However, I've never managed to reproduced the productive REPL workflow I had in Clojure with those languages; the truth is that not all REPLs are created equal. Basically, the "REPL" you usually call a REPL is in fact a shell, and not a REPL as normally used in lisp languages.
  - kbelder 5y ago
    I think FORTH has something very similar to the lisp REPL, if I'm understanding it properly. I know little of lisp, but everything I've read makes it seem that it and FORTH are almost evil twins of each other. Opposite but equal.
  - Zababa 5y ago
    Thanks, from what I understand the difference I made between having a REPL and being able to do REPL-driven development is the one you make between a shell and a REPL.
draegtun 5y ago
Rebol / Red also have a reader though in its terminology it could be called a "loader". See LOAD function - http://rebol.com/docs/words/wload.html http://rebol.com/docs/words/wload.html

Only Lisps have a reader so I'm not sure the term REPL is accurate with other languages. Interactive console != REPL.

by cutler 5y ago

Only Lisps have a reader so I'm not sure the term REPL is accurate with other languages. Interactive console != REPL.

Could you expand on that? I've searched a bit but the Lisp read doesn't sound too different from what other languages do.

simiones 5y ago
Unlike most languages, Lisp defines how strings can be transformed to Lisp ASTs (s-expressions). In Scheme (which doesn't allow reader macros) this is a safe operation: you can read untrusted input without worry. By contrast, most other languages only have eval() - which takes a string and parses and executes it as code. In Lisp, eval() takes a Lisp list object and executes that.
- draegtun 5y ago
  Ditto for Rebol & Red. For eg. >> code: load "foreach n [1 2 3 4] [print n * 2]" == [foreach n [1 2 3 4] [print n * 2] ] >> type? code == block! >> do code 2 4 6 8
capableweb 5y ago
This is probably the best blog post I've seen on the topic: https://vvvvalvalval.github.io/posts/what-makes-a-good-repl.html https://vvvvalvalval.github.io/posts/what-makes-a-good-repl.... > If you're not familiar with Clojure, you may be surprised that I describe the REPL as Clojure's most differentiating feature: after all, most industrial programming languages come with REPLs or 'shells' these days (including Python, Ruby, Javascript, PHP, Scala, Haskell, ...). However, I've never managed to reproduced the productive REPL workflow I had in Clojure with those languages; the truth is that not all REPLs are created equal. Basically, the "REPL" you usually call a REPL is in fact a shell, and not a REPL as normally used in lisp languages.
- kbelder 5y ago
  I think FORTH has something very similar to the lisp REPL, if I'm understanding it properly. I know little of lisp, but everything I've read makes it seem that it and FORTH are almost evil twins of each other. Opposite but equal.
- Zababa 5y ago
  Thanks, from what I understand the difference I made between having a REPL and being able to do REPL-driven development is the one you make between a shell and a REPL.

draegtun 5y ago

Rebol / Red also have a reader though in its terminology it could be called a "loader". See LOAD function - http://rebol.com/docs/words/wload.html http://rebol.com/docs/words/wload.html