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0 pointsgjulianm3y ago0 comments

> APL shows 74 symbols. I count at least 50 math symbols that seem very likely to show up in an undergraduate degree; notably, 26 symbols +-×÷|⌊⌈!~∧∨⍲⍱<≤=≥>≠∊∩∪≡≢∘ in APL are taken from math with similar meanings.

I have counted at least 30 symbols that I haven’t seen in an undergraduate degree + master degree, not counting symbols that I know but haven’t seen used directly as symbols (eg , or ?) but as punctuation. Of course I might have forgotten some of them but I think it’s undeniable that APL introduces a lot of new symbols.

> The arguments to a primitive are not context! You may as well call addition context-dependent because 1+n increments n while 2+n increments it twice. You're describing overloading

Not the arguments themselves but the amount of arguments. Operator overloading is also context dependency. Maybe we’re getting lost in the words: what I mean is that you can’t say for sure what a certain symbol means unless you have the symbols around it. For example, in C / always means “divide what’s on the left by what’s on the left”, but * is context dependent because it can either be multiplication or pointer dereference.

> That is, maybe symbols encourage this design choice, but in themselves they aren't the problem.

If some part of a language encourages things that we consider bad decisions, then that part is a problem. Again returning to C, one could say that the memory allocation system isn’t a problem despite the fact that it makes it really easy to cause leaks and bad memory accesses.

> A language with 74 symbols, many of which are related, is what makes it possible to teach APL quickly

Quickly… compared to what? Because I honestly don’t think an average person is going to learn APL faster than any mainstream language.

> APL was near-mainstream in the 1980s, and I think there are better explanations for its decline since.

It’s not just that APL has declined but in general the array programming paradigm that it pioneered hasn’t really taken off. For example, LISP declined quite a lot but new similar, functional languages have appeared and attracted interest.

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5 comments · 4 top-level

avmich3y ago· 1 in thread

J uses ASCII. Built-in symbols use dot (.) and colon (:) as part of a symbol. In J vocabulary, https://www.jsoftware.com/help/dictionary/vocabul.htm , I counted less than 150 built-in symbols. Even if you double it as monadic/dyadic variations, that's less than 300. I definitely don't know many of them, and still able to write some programs, like a parser generator; I think those symbols are closer to a standard library - i.e. with C we need to get familiar with printf, getc or strcpy. As with mathematics in elementary school, you start with few simpler ones, then gradually add some more useful ones, then the rest is optional for cases when you want or need them.

In practice a lot of J symbols are either already known or rather obvious.

gjulianmOP3y ago

It's like a standard library except it's harder to search for the symbol you want via autocomplete, harder to infer the meaning of symbols you don't know (even when the C standard library has some terrible names) and easier to confuse (from the page, having symbols like ,. and .. or ,: and .:).

Of course, I assume that people end up knowing most of them and that not all of them are necessary. I'm not arguing that, I'm saying that symbols are an extra cognitive load and I find it funny that the argument for them is "well this is how is done in math" when precisely there's a push in math to avoid using excessive symbols.

avmich3y ago

> Quickly… compared to what? Because I honestly don’t think an average person is going to learn APL faster than any mainstream language.

It's known that non-professional programmers often preferred APL to other languages, it was easier to express their problems in APL than in something else.

mlochbaum3y ago

A possible point of confusion: "I count at least 50 math symbols" wasn't in reference to APL, just my count of how many symbols are widely used in mathematics. Contrasting your claim that APL has "far more symbols than I've ever seen in my math degree". Agreed, most of APL's symbols are not found in mathematics.

I refer you again to Perlis, same paragraph: "It is true that BASIC and FORTRAN are easier to learn than APL, for example, a week versus a month. However, once mastered, APL fits the above requirements much better than either BASIC or FORTRAN or their successors ALGOL 60, PL/I and Pascal."

avmich3y ago

> For example, in C / always means “divide what’s on the left by what’s on the left”, but * is context dependent because it can either be multiplication or pointer dereference.

No, it could mean a start of a comment. Multi-line or single-line - depends on context. Similarly, there are multi-character operators - both in C and J. And while some idioms in APL could be seen as "atomic" (like (+/ % #) in J), they are actually a function composition, so they'd better be seen and understood in context, which is rather small.

j / k navigate · click thread line to collapse

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5 comments · 4 top-level

avmich3y ago· 1 in thread

In practice a lot of J symbols are either already known or rather obvious.

gjulianmOP3y ago

avmich3y ago

> Quickly… compared to what? Because I honestly don’t think an average person is going to learn APL faster than any mainstream language.

It's known that non-professional programmers often preferred APL to other languages, it was easier to express their problems in APL than in something else.

mlochbaum3y ago

avmich3y ago

> For example, in C / always means “divide what’s on the left by what’s on the left”, but * is context dependent because it can either be multiplication or pointer dereference.

j / k navigate · click thread line to collapse