3 ms·

I know I'm not as smart as you guys, but I very strongly prefer 3 + 4 + (1 - 3/4) + ((9-2) * 8 * 3) If you code Lisp long enough does your first expression bec

I know I'm not as smart as you guys, but I very strongly prefer 3 + 4 + (1 - 3/4) + ((9-2) * 8 * 3) If you code Lisp long enough does your first expression becomes as natural to read as my expression is for me?

brlewis 19y ago
It becomes just as natural, and it's easier to debug. You can drop down lines and autoindent to see the structure of the mathematical forumula. I don't know of any editors that will do that sort of thing for infix.
anamax 19y ago
I note that infix was so natural that you resorted to parens. Infix looks reasonable until one has more than 2 operators. Then people start making mistakes. To combat those mistakes, they start parenthesizing. The number of mistakes goes down but there's still confusion. (Some folks know more precedence levels than others and many folks think that they know precedence levels that they don't know.)
- curi 19y ago
  not only that, 2 of the 3 sets of paren were not needed, the order of operations already would have gotten it right
  - anamax 19y ago
    Not necessarily. Infix precedence/associativity is so "natural" that different languages have have different precedences or associativity for the same operator. If one works in multiple languages, the only safe thing is to ignore precedence and associativity and parethesize everything.
    - curi 19y ago
      cool. which of the basic arithmetic operators have difference precedence in which languages? what i am used to is * and / first, then + and -.
      - anamax 19y ago
        apl for one. And then there's associativity. It doesn't much matter for * and +, but it matters a lot for / and -, and if you think that * and / have the same precedence, it matters for . And, you're continuing to ignore the fact that there are far more infix operators. Even if infix worked for +-/, that doesn't tell us that it works when there's .,->,<, &, ?, %, $, #, @, ~, ^, |, \, =, and so on (such as digraphs). No language that uses infix has resisted the temptation to extend it past the point where it causes more problems than it solves.
        curi 19y ago
        I think you may have mixed people up, I've been arguing against infix, so I'm not continuing to ignore that ;p I believe I posted a comment pointing out that lots of people aren't completely sure, offhand, if && or == has higher precedence. And even in this branch of the thread, when I said he could have omitted some of the parentheses, I didn't mean to say infix is powerful because it can use less parenthesis. it gets rid of them with a dirty trick that doesn't scale. What I was pointing out is that people don't actually know the infix precedence rules by heart (like they try to say they do. they say it's so natural...). so they end up putting parenthesis frequently just cause they aren't sure.
- WilliamLP 19y ago
  Another way to put that is that Lisp is so natural it resorts to forcing parens everywhere even when I don't want them! I'd never deny that confusion about order of operations between &, |, ==, <<, %, and so on, is a major source of bugs. (But I'd blame poor coding style for that, in any language, in the first place.) However, in every field besides this niche of computer science, including almost all of math, finance, science, and engineering, infix is used. This means that it is at least good enough and I suspect it has advantages. Many math operations really are just fundamentally unary or binary. Generalizing - or / or x^y or mod to lists is just silly as far as I can see, and adds confusion. I don't need to see parens around the outermost operation. For the two most common associative operations, + and *, order of operations is quite good enough and it has the advantage that everyone since grade 6 has been working with it. (I'll give you that there are very many cases where list notation is great, but I don't think it's common that they help very much in science, business, or engineering.)
  - projectileboy 19y ago
    Forgive my total ignorance; do the kids today not use HP calculators? When I was in college (+/- 1990), we all had HP calculators, and so thinking in terms of (+ 1 2 3 4) felt pretty natural.
    - rms 19y ago
      Nope. TI graphing calculators are basically standard. TI-83 is standard in high school and a TI-89 is preferred by those who know how much symbolic manipulation and calculus can improve their grades. They both do infix order of operations. I believe what is popular right now with new calculator buyers are the versions of the TI-83 and TI-89 with USB connectors and faster processors, I think they're called the TI-84 and TI-89 Titanium.
  - anamax 19y ago
    > However, in every field besides this niche of computer science, including almost all of math, finance, science, and engineering, infix is used. The reason is that the "reader" in all of those domains is another human and humans do error correction almost without thinking. Also, each of those domains has a very small number of operators - programming languages have lots of operators. Feel free to demonstrate that you know the precedence/associativity rules for your favorite programming language by typing them without looking them up. (I know two people who can do that for C; the vast majority can't.)
parenthesis 19y ago
Prefix arithmetic is easier to read: (+ 3 4 (- 1 (/ 3 4) (* (- 9 2) 8 3)) You can see straight away that the whole thing is one big addition; that the third summand is a subtraction, etc.. Also, a lot of math is prefix: f(x,y) ; d/dx (...) etc..
- ivankirigin 19y ago
  I never understood why this was an issue. People are really used to writing prefix functions in all languages def foo( bar, baz): And I've never really had a hard time with reading arithmatic, so the debate really leaves me scratching my head.
hollerith 19y ago
not if you used infix notation for + - * / as a child e.g. in school and learned Lisp after age 16 -- at least that is my experience.

brlewis 19y ago

It becomes just as natural, and it's easier to debug. You can drop down lines and autoindent to see the structure of the mathematical forumula. I don't know of any editors that will do that sort of thing for infix.

anamax 19y ago

I note that infix was so natural that you resorted to parens. Infix looks reasonable until one has more than 2 operators. Then people start making mistakes. To combat those mistakes, they start parenthesizing. The number of mistakes goes down but there's still confusion. (Some folks know more precedence levels than others and many folks think that they know precedence levels that they don't know.)

curi 19y ago
not only that, 2 of the 3 sets of paren were not needed, the order of operations already would have gotten it right
- anamax 19y ago
  Not necessarily. Infix precedence/associativity is so "natural" that different languages have have different precedences or associativity for the same operator. If one works in multiple languages, the only safe thing is to ignore precedence and associativity and parethesize everything.
  - curi 19y ago
    cool. which of the basic arithmetic operators have difference precedence in which languages? what i am used to is * and / first, then + and -.
    - anamax 19y ago
      apl for one. And then there's associativity. It doesn't much matter for * and +, but it matters a lot for / and -, and if you think that * and / have the same precedence, it matters for . And, you're continuing to ignore the fact that there are far more infix operators. Even if infix worked for +-/, that doesn't tell us that it works when there's .,->,<, &, ?, %, $, #, @, ~, ^, |, \, =, and so on (such as digraphs). No language that uses infix has resisted the temptation to extend it past the point where it causes more problems than it solves.
      - curi 19y ago
        I think you may have mixed people up, I've been arguing against infix, so I'm not continuing to ignore that ;p I believe I posted a comment pointing out that lots of people aren't completely sure, offhand, if && or == has higher precedence. And even in this branch of the thread, when I said he could have omitted some of the parentheses, I didn't mean to say infix is powerful because it can use less parenthesis. it gets rid of them with a dirty trick that doesn't scale. What I was pointing out is that people don't actually know the infix precedence rules by heart (like they try to say they do. they say it's so natural...). so they end up putting parenthesis frequently just cause they aren't sure.
WilliamLP 19y ago
Another way to put that is that Lisp is so natural it resorts to forcing parens everywhere even when I don't want them! I'd never deny that confusion about order of operations between &, |, ==, <<, %, and so on, is a major source of bugs. (But I'd blame poor coding style for that, in any language, in the first place.) However, in every field besides this niche of computer science, including almost all of math, finance, science, and engineering, infix is used. This means that it is at least good enough and I suspect it has advantages. Many math operations really are just fundamentally unary or binary. Generalizing - or / or x^y or mod to lists is just silly as far as I can see, and adds confusion. I don't need to see parens around the outermost operation. For the two most common associative operations, + and *, order of operations is quite good enough and it has the advantage that everyone since grade 6 has been working with it. (I'll give you that there are very many cases where list notation is great, but I don't think it's common that they help very much in science, business, or engineering.)
- projectileboy 19y ago
  Forgive my total ignorance; do the kids today not use HP calculators? When I was in college (+/- 1990), we all had HP calculators, and so thinking in terms of (+ 1 2 3 4) felt pretty natural.
  - rms 19y ago
    Nope. TI graphing calculators are basically standard. TI-83 is standard in high school and a TI-89 is preferred by those who know how much symbolic manipulation and calculus can improve their grades. They both do infix order of operations. I believe what is popular right now with new calculator buyers are the versions of the TI-83 and TI-89 with USB connectors and faster processors, I think they're called the TI-84 and TI-89 Titanium.
- anamax 19y ago
  > However, in every field besides this niche of computer science, including almost all of math, finance, science, and engineering, infix is used. The reason is that the "reader" in all of those domains is another human and humans do error correction almost without thinking. Also, each of those domains has a very small number of operators - programming languages have lots of operators. Feel free to demonstrate that you know the precedence/associativity rules for your favorite programming language by typing them without looking them up. (I know two people who can do that for C; the vast majority can't.)

parenthesis 19y ago

Prefix arithmetic is easier to read: (+ 3 4 (- 1 (/ 3 4) (* (- 9 2) 8 3)) You can see straight away that the whole thing is one big addition; that the third summand is a subtraction, etc.. Also, a lot of math is prefix: f(x,y) ; d/dx (...) etc..

ivankirigin 19y ago
I never understood why this was an issue. People are really used to writing prefix functions in all languages def foo( bar, baz): And I've never really had a hard time with reading arithmatic, so the debate really leaves me scratching my head.

hollerith 19y ago

not if you used infix notation for + - * / as a child e.g. in school and learned Lisp after age 16 -- at least that is my experience.