4 ms·

If you take a look at my reply to TazeTSchnitzel you'll see that I "solved" (I think? at least tried to) this problem with indentation (generally whitespace. Yo

If you take a look at my reply to TazeTSchnitzel you'll see that I "solved" (I think? at least tried to) this problem with indentation (generally whitespace. You can delimit expressions in many ways. And in Forth case, you can very easily define your own delimiters: : [ ; : ] ; which should make you able to write: [ [ 1 2 + ] [ 3 4 + ] * ] . 21 ok (tested with gforth and works [EDIT: but of course breaks Forth! Both [ and ] are already defined, so in practice you'd rather choose another chars]) I mean, there is no rule saying that postfix notation cannot provide grouping constructs. I still fail to see a fundamental difference here :) BTW, it's not going as fast as I'd like, but I managed to parse TXR man page and use it for displaying docs along auto-completion: https://github.com/piotrklibert/txr-mode/blob/master/screen.png https://github.com/piotrklibert/txr-mode/blob/master/screen.... I think I'll be able to find some time this weekend (or next weekend) to clean up the code and make it usable for others as well :)

kazinator 11y ago
Whitespace that is not significant to the machine does nothing to help me convince myself that the code is correct. Indentation could be wrong. If I already know that the code is correct and properly indented, then it helps the readability. > And in Forth case, you can very easily define your own delimiters: Those delimiters do nothing but occupy interpreter cycles. Hopefully they get recognized as noops and optimized away by a Forth compiler. The machine will accept garbage like: ] 3 2 + [ 4 / The fake syntax you've created is there is sort of like a cargo cult airplane made out of bamboo sticks and palm leaves. It has some value as an annotation of correct code, that is all. It could be a useful annotation tool in the process of verifying a piece of code and convincing myself that it's correct. Forth should have these markers built-in so they don't have to be defined as words, and it should check their pairing and nesting. (A syntax highlighting engine can be taught to do that, of course.)
- klibertp 11y ago
  > Whitespace that is not significant to the machine does nothing to help me convince myself that the code is correct. Indentation could be wrong. A sloppily written code is hard to understand correctly in every language (to different degrees, of course). You can easily mistake if (...) do1(); do2(); for if (...) { do1(); do2(); } right? This is C - an infix language - and it's arguably its fault for providing this stupid form, but you usually don't judge how readable infix notation is based on this. > Those delimiters do nothing but occupy interpreter cycles. Hopefully they get recognized as noops and optimized away by a Forth compiler. I'd expect so. > The machine will accept garbage like: > ] 3 2 + [ 4 / Yup. And by the way, this garbage is actually nearly correct J code. One possible fix would look like: ] 3 2 + [ 4 (+ /) [ 4 this gives `10 11` as an answer (and please don't ask me why...). ] and [ are left and right identity functions, they simply do nothing, so they may be inserted in many places, in many cases interchangeably. > Forth should have these markers built-in so they don't have to be defined as words, and it should check their pairing and nesting. That's unnecessary in Forth, I'm sure you can implement a "real" - with a semantic meaning - grouping in Forth yourself. Comments in Forth are enclosed in parens, and the parens are normal Forth words, defined in Forth. I mean, it's already a grouping syntax with a DROP semantics; you can probably define grouping syntax with other semantics as well. Also, in Forth there are only words, and the syntax is that simple, but that isn't a property of all postfix languages. We're talking about postfix as a notation in general, not about it's particular brand practiced by Forth. This is why I keep mentioning J, again and again: it's an infix language. I could bash infix notation forever had I used J as an example! It's the same with postfix notation and Forth.

kazinator 11y ago

Whitespace that is not significant to the machine does nothing to help me convince myself that the code is correct. Indentation could be wrong. If I already know that the code is correct and properly indented, then it helps the readability. > And in Forth case, you can very easily define your own delimiters: Those delimiters do nothing but occupy interpreter cycles. Hopefully they get recognized as noops and optimized away by a Forth compiler. The machine will accept garbage like: ] 3 2 + [ 4 / The fake syntax you've created is there is sort of like a cargo cult airplane made out of bamboo sticks and palm leaves. It has some value as an annotation of correct code, that is all. It could be a useful annotation tool in the process of verifying a piece of code and convincing myself that it's correct. Forth should have these markers built-in so they don't have to be defined as words, and it should check their pairing and nesting. (A syntax highlighting engine can be taught to do that, of course.)

klibertp 11y ago
> Whitespace that is not significant to the machine does nothing to help me convince myself that the code is correct. Indentation could be wrong. A sloppily written code is hard to understand correctly in every language (to different degrees, of course). You can easily mistake if (...) do1(); do2(); for if (...) { do1(); do2(); } right? This is C - an infix language - and it's arguably its fault for providing this stupid form, but you usually don't judge how readable infix notation is based on this. > Those delimiters do nothing but occupy interpreter cycles. Hopefully they get recognized as noops and optimized away by a Forth compiler. I'd expect so. > The machine will accept garbage like: > ] 3 2 + [ 4 / Yup. And by the way, this garbage is actually nearly correct J code. One possible fix would look like: ] 3 2 + [ 4 (+ /) [ 4 this gives `10 11` as an answer (and please don't ask me why...). ] and [ are left and right identity functions, they simply do nothing, so they may be inserted in many places, in many cases interchangeably. > Forth should have these markers built-in so they don't have to be defined as words, and it should check their pairing and nesting. That's unnecessary in Forth, I'm sure you can implement a "real" - with a semantic meaning - grouping in Forth yourself. Comments in Forth are enclosed in parens, and the parens are normal Forth words, defined in Forth. I mean, it's already a grouping syntax with a DROP semantics; you can probably define grouping syntax with other semantics as well. Also, in Forth there are only words, and the syntax is that simple, but that isn't a property of all postfix languages. We're talking about postfix as a notation in general, not about it's particular brand practiced by Forth. This is why I keep mentioning J, again and again: it's an infix language. I could bash infix notation forever had I used J as an example! It's the same with postfix notation and Forth.