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Like any language, Lisp has readability issues when you’re not familiar with it. You find it hard to read because it’s alien to you. To my eyes – because Lisp i

by Oreb 4y ago

Like any language, Lisp has readability issues when you’re not familiar with it. You find it hard to read because it’s alien to you. To my eyes – because Lisp is what I’m used to – every non-Lisp language has readability issues. These days I do a significant amount of work in Python, Rust and Julia, and although there are things I love in all of these languages, I always miss s-expression syntax when using them.

kazinator 4y ago
Infix notation can be useful for arithmetic; as a "Lisp person" I acknowledge that. S-exps can be good for arithmetic too though. S-expressions allow n-ary operators: (+ (* 3 x y) (* a b z w) (* r s t u v)) There is a systematic way to break up large expressions across multiple lines, which helps readability. Infix doesn't have a satisfactory way to do this: (+ (* 3 x y) (* a b z w) (* r s t u v)) We see just from from the + * * * pattern that we have a sum of three products. S-exps are unambiguous. You never misread an arithmetic (or any other) S-exp due to precedence, unless it's a macro that has created precedence rules among its arguments (vanishingly rare). N-ary math functions associate left to right in Common LIsp: (+ a b c d) means we add (a b) first, then c, and d. This makes a difference when you have mixed types, which have to undergo conversions, and when you have non-associative types like floating-point. If I'm cribbing some numeric calculation to use in my code (whether that code is Lisp or not), and have examples in half a dozen languages, none of which I use, I will crib it from that one that is a Lisp dialect, just because of the vanishingly small opportunity for getting it wrong due to some ambiguity issue.
- deleted 4y ago
  [deleted]
- jstimpfle 4y ago
  This is a comment that I like, acknowledging the obvious unsophisticated but no less reasonable objection from the bystanders, and offering them an alternate viewpoint. My reservation would be that most applications of arithmetic operators are binary and not ternary. A typical expression in one of my C programs at least has some function call, some subscript, some member access, some addition / subtraction / multiplication / division. But very few have more than one of each. Overall arithmetic is actually quite rare by itself in most code.
whartung 4y ago
My windmill is simply I still can't think in prefix for math. It's trivial for me to write x = (-b + sqrt(b^2 + 4 * a * c)) / (2 * a). But writing (setf x (/ (+ (- b) (sqrt (+ (* 4 a c) (* b b)))) (* 2 a))). That's a mind bender. Were this my source code, I'd probably put the (* 2 a) on the next line (properly indented) so it stood out as the divisor. All that said, honestly, the physical task of writing Lisp code is just so much better than anything else. There's something satisfying closing up all of the parens. And I just love using-hyphens-for-identifiers vs CamelCase or using_underscores.
- Jach 4y ago
  Fortunately doing infix math in CL has since the 90s been one small library include away: https://github.com/quil-lang/cmu-infix https://github.com/quil-lang/cmu-infix
  - jstimpfle 4y ago
    That's nice but we can all agree that it's not the same thing as a standard builtin syntax that everyone knows and is forced to use.
    - reikonomusha 4y ago
      I think you're writing it off as not actually being valuable in practice, which I don't think is fair. Should we consider Python's NumPy as not a feature of Python because it's not a built-in library? A commenter says they prefer to write infix math. Lisp has a completely ordinary, stable, well-known, 30-year-old library to do it. Thus the commenter's concerns are largely allayed. Not having it in the standard library means people have a choice to use it or not, and it also means one can't expect all Lisp code which has infix math to use it, but it certainly does not means the commenter will be perpetually hamstrung in reading and writing complicated math formulas.
      - lmm 4y ago
        Macros are a cure that's worse than the disease. Unless everyone agrees on which set of macros you're using, you can't trust any code to mean what it looks like it means. (And if you could agree on which set of macros you were using, or what sanity-preserving restrictions you'd put on your macros, surely you'd just build those into your language).
Joel_Mckay 4y ago
"alien to you" Nope, but I do classify lisp/scheme next to Haskell, Icon/Unicon, and snowball... as ivory-tower languages. However, you wouldn't be the first person to spend 3 years of their lives failing to prove the assertion false. Is there utility assuming everyone who doesn't share your opinion is an Alien? I find it just causes the 103rd purple proboscis to itch. ;)

by Oreb 4y ago

kazinator 4y ago

Infix notation can be useful for arithmetic; as a "Lisp person" I acknowledge that. S-exps can be good for arithmetic too though. S-expressions allow n-ary operators: (+ (* 3 x y) (* a b z w) (* r s t u v)) There is a systematic way to break up large expressions across multiple lines, which helps readability. Infix doesn't have a satisfactory way to do this: (+ (* 3 x y) (* a b z w) (* r s t u v)) We see just from from the + * * * pattern that we have a sum of three products. S-exps are unambiguous. You never misread an arithmetic (or any other) S-exp due to precedence, unless it's a macro that has created precedence rules among its arguments (vanishingly rare). N-ary math functions associate left to right in Common LIsp: (+ a b c d) means we add (a b) first, then c, and d. This makes a difference when you have mixed types, which have to undergo conversions, and when you have non-associative types like floating-point. If I'm cribbing some numeric calculation to use in my code (whether that code is Lisp or not), and have examples in half a dozen languages, none of which I use, I will crib it from that one that is a Lisp dialect, just because of the vanishingly small opportunity for getting it wrong due to some ambiguity issue.

deleted 4y ago
[deleted]
jstimpfle 4y ago
This is a comment that I like, acknowledging the obvious unsophisticated but no less reasonable objection from the bystanders, and offering them an alternate viewpoint. My reservation would be that most applications of arithmetic operators are binary and not ternary. A typical expression in one of my C programs at least has some function call, some subscript, some member access, some addition / subtraction / multiplication / division. But very few have more than one of each. Overall arithmetic is actually quite rare by itself in most code.

whartung 4y ago

My windmill is simply I still can't think in prefix for math. It's trivial for me to write x = (-b + sqrt(b^2 + 4 * a * c)) / (2 * a). But writing (setf x (/ (+ (- b) (sqrt (+ (* 4 a c) (* b b)))) (* 2 a))). That's a mind bender. Were this my source code, I'd probably put the (* 2 a) on the next line (properly indented) so it stood out as the divisor. All that said, honestly, the physical task of writing Lisp code is just so much better than anything else. There's something satisfying closing up all of the parens. And I just love using-hyphens-for-identifiers vs CamelCase or using_underscores.

Jach 4y ago
Fortunately doing infix math in CL has since the 90s been one small library include away: https://github.com/quil-lang/cmu-infix https://github.com/quil-lang/cmu-infix
- jstimpfle 4y ago
  That's nice but we can all agree that it's not the same thing as a standard builtin syntax that everyone knows and is forced to use.
  - reikonomusha 4y ago
    I think you're writing it off as not actually being valuable in practice, which I don't think is fair. Should we consider Python's NumPy as not a feature of Python because it's not a built-in library? A commenter says they prefer to write infix math. Lisp has a completely ordinary, stable, well-known, 30-year-old library to do it. Thus the commenter's concerns are largely allayed. Not having it in the standard library means people have a choice to use it or not, and it also means one can't expect all Lisp code which has infix math to use it, but it certainly does not means the commenter will be perpetually hamstrung in reading and writing complicated math formulas.
    - lmm 4y ago
      Macros are a cure that's worse than the disease. Unless everyone agrees on which set of macros you're using, you can't trust any code to mean what it looks like it means. (And if you could agree on which set of macros you were using, or what sanity-preserving restrictions you'd put on your macros, surely you'd just build those into your language).

Joel_Mckay 4y ago

"alien to you" Nope, but I do classify lisp/scheme next to Haskell, Icon/Unicon, and snowball... as ivory-tower languages. However, you wouldn't be the first person to spend 3 years of their lives failing to prove the assertion false. Is there utility assuming everyone who doesn't share your opinion is an Alien? I find it just causes the 103rd purple proboscis to itch. ;)