4 ms·

It depends on what you are trying to optimize for. There is a benefit to punning the empty list and boolean false. It lets you shorten (not (null x)) to just

by lisper 2y ago

It depends on what you are trying to optimize for. There is a benefit to punning the empty list and boolean false. It lets you shorten (not (null x)) to just x, and that is a common enough idiom that it actually makes a difference in real code. And there is a benefit to being able to say or type "nil" instead of "the empty list" because "nil" is shorter. But yeah, for modern production code, I agree that stricter is better, all else being equal.

pmarreck 2y ago
I love that I started out saying "I'm not a LISPer" and someone whose username is literally "lisper" responded. >..< Is there a purely functional Lisp that compiles to machine code yet?
- lisper 2y ago
  That depends on what you mean by "purely functional Lisp". You can write purely functional code in any Lisp, and you can compile any Lisp to machine language, and this has been true for decades. AFAIK there is no Lisp that enforces purely functional programming, but it's easy to build one if that's what you want.
  - pmarreck 2y ago
    That is what I want. Turns out that LFE (Lisp-Flavored Erlang) exists… Wait, doesn’t Clojure have this, to a large degree at least?
pmarreck 2y ago
sorry for another lisp question if from a syntactic-flavor perspective, endless parentheses turn me off, but also cleanly map to significant indentation (where any new open paren is a new indentation level and a close paren maps to a backdent), has anyone tried a Lisp that uses indentation instead of parens? I'm probably failing to consider edge cases but it seems like a potentially simple tweak that might make lisps more palatable to many imagine that, a lisp without parens... (empty cons literals... crap, that's 1 edge case!)
- lisper 2y ago
  What do you think is more likely, that you are the first person to ever think of this, or that others have tried to do this and failed for some reason? The more interesting question is: what is that reason? I'm not going to tell you the answer, you will learn more if you figure it out yourself, but here's a hint: look at Python's syntax, and ask yourself if it is possible to write an editor that auto-indents Python. (Second hint: look at what happens when you edit Python code in Emacs. Third hint: look at what happens when you put in PASS statements.)
  - pmarreck 2y ago
    I never suggested that I was the first person to think of this; not having dealt with any Lisp since (hmmm) 1990 via Scheme in my introductory CS 212 class at Cornell probably has something to do with my ignorance of the prior art in this area. I do like your approach of breadcrumbing me instead of giving me the answer, though... best I can guess is "tooling" and simply that S-expressions are simply too embedded in the minds of the Lisp community at this (or previous) point(s). I also don't deal with significant-indentation in languages usually (and have a strong Python distaste); though I've been playing with Roc (https://www.roc-lang.org/ https://www.roc-lang.org/), which has this, and have used HAML (https://haml.info/ https://haml.info/) in the past, where it seemed useful. I suppose auto-indenting is impossible in a significant-indentation language depending on what the editor can intuit based on how the previous line ended, but I don't think I'd need that feature as long as it simply held the current indentation and just let me hit Tab or Backspace. (I could see things becoming a mess if you manage to screw up the indentation, though.) I did research "sweet expressions" (which are apparently also called T-expressions) and found the prior art there in Scheme and Lisp, and a library called "sweet" for Racket (which is another intriguing lisp dialect!). These might have gotchas, but apparently they've sufficiently solved the problem enough to be usable. I do simply like how "T-expressions" look. Which is something I guess I care about, although I know that's not a universal among coders. (My guess is that those who care about such things are simply not 100% left-brained about their coding and are invested in the "writing" aspect of the craft.)
- kazinator 2y ago

by lisper 2y ago

pmarreck 2y ago

I love that I started out saying "I'm not a LISPer" and someone whose username is literally "lisper" responded. >..< Is there a purely functional Lisp that compiles to machine code yet?

lisper 2y ago
That depends on what you mean by "purely functional Lisp". You can write purely functional code in any Lisp, and you can compile any Lisp to machine language, and this has been true for decades. AFAIK there is no Lisp that enforces purely functional programming, but it's easy to build one if that's what you want.
- pmarreck 2y ago
  That is what I want. Turns out that LFE (Lisp-Flavored Erlang) exists… Wait, doesn’t Clojure have this, to a large degree at least?

pmarreck 2y ago

sorry for another lisp question if from a syntactic-flavor perspective, endless parentheses turn me off, but also cleanly map to significant indentation (where any new open paren is a new indentation level and a close paren maps to a backdent), has anyone tried a Lisp that uses indentation instead of parens? I'm probably failing to consider edge cases but it seems like a potentially simple tweak that might make lisps more palatable to many imagine that, a lisp without parens... (empty cons literals... crap, that's 1 edge case!)

lisper 2y ago
What do you think is more likely, that you are the first person to ever think of this, or that others have tried to do this and failed for some reason? The more interesting question is: what is that reason? I'm not going to tell you the answer, you will learn more if you figure it out yourself, but here's a hint: look at Python's syntax, and ask yourself if it is possible to write an editor that auto-indents Python. (Second hint: look at what happens when you edit Python code in Emacs. Third hint: look at what happens when you put in PASS statements.)
- pmarreck 2y ago
  I never suggested that I was the first person to think of this; not having dealt with any Lisp since (hmmm) 1990 via Scheme in my introductory CS 212 class at Cornell probably has something to do with my ignorance of the prior art in this area. I do like your approach of breadcrumbing me instead of giving me the answer, though... best I can guess is "tooling" and simply that S-expressions are simply too embedded in the minds of the Lisp community at this (or previous) point(s). I also don't deal with significant-indentation in languages usually (and have a strong Python distaste); though I've been playing with Roc (https://www.roc-lang.org/ https://www.roc-lang.org/), which has this, and have used HAML (https://haml.info/ https://haml.info/) in the past, where it seemed useful. I suppose auto-indenting is impossible in a significant-indentation language depending on what the editor can intuit based on how the previous line ended, but I don't think I'd need that feature as long as it simply held the current indentation and just let me hit Tab or Backspace. (I could see things becoming a mess if you manage to screw up the indentation, though.) I did research "sweet expressions" (which are apparently also called T-expressions) and found the prior art there in Scheme and Lisp, and a library called "sweet" for Racket (which is another intriguing lisp dialect!). These might have gotchas, but apparently they've sufficiently solved the problem enough to be usable. I do simply like how "T-expressions" look. Which is something I guess I care about, although I know that's not a universal among coders. (My guess is that those who care about such things are simply not 100% left-brained about their coding and are invested in the "writing" aspect of the craft.)
kazinator 2y ago