Readit Newsrabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
No. They are not keywords. The program:
is the same as:
Thanks for explaining!
But how about this example:
It results in
It seems like you can define variables with the name 'x', but when you do not have explicit parameters, then the identifier 'x' is used to refer to the first implicit parameter, y - for second and z - for the third parameter. In context of implicit parameters x, y and z acts like predefined keywords.
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
They're just variables like any other; {[x;y;z] x+yz} is almost exactly the same as {x+yz}
I tested and seems, that x is the first implicit parameter, y - second, z - third. It is as stated in their online documentation.
When you try following example:
{y+x*z}[1;2;3]
5
And in Q you cannot define implicit parameters with names, for example,: a, b, c. But You can define parameters explicitly:
{[a;b;c]a+b*c}[1;2;3]
In KatLang there are no predefined implicit parameter names. The user is the one who defines implicit parameters by declaring the implicit parameter names.
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
I think they meant:
A1 = x * y + x
A2 = y * x + yA1 in Javascript pseudocode would be:
function A1(x, y) {return x*y + x; }
function A2(y, x) {return y*x + y; }
A1 = y~ * x + y
A1 = y * ~x + y
A1 = y * x + y~
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
They're just variables like any other; {[x;y;z] x+yz} is almost exactly the same as {x+yz}
Can you explain the difference little bit more, Maybe using Javascript pseudocode as comparable example? I want to understand how Q is different from KatLang. The problem with me is that I do not know where I can try Q code, therefore I rely only on the documentation fragments I can find.
rabarbers commented on Show HN: I built an online programming language codigo.so... · Posted by u/sandes
It's a multi-language pseudocode interpreter so you can write and run code in English, Spanish, Portuguese and French in your browser.
Link to documentation is broken: https://codigo.so/docs/ (also link to community is broken, but I care more about Documentation link).
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
Yes, the first unknown identifier becomes the first parameter, next unknown identifier becomes next parameter and so on...
More specifically: the first unknown identifier becomes the first parameter for the closest algorithm defined with {} brackets. Properties (also called named algorithms) are defined as {} context. And KatLang program also is defined as {} context. I call it Second order algorithm - algorithms can contain another algorithms. First order algorithm is something defined between commas or semicolons. But inside brackets () or {} you can define second order algorithm.
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
> But regarding languages: k/q the issues with them is that they use x, y and z as keywords for the parameters. x is always the first parameter, y - second, z - third. In KatLang parameter names are not predefined keywords, you can pick almost any parameter names you like.
They aren't in q either: x can be redefined to whatever you like.
How does KatLang determine which argument is first? Is it merely the first free variable?
According to Q documentation, Q supports only 3 implicit parameters x, y, z: https://web.archive.org/web/20190213035913/http://code.kx.co...
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
> But regarding languages: k/q the issues with them is that they use x, y and z as keywords for the parameters. x is always the first parameter, y - second, z - third. In KatLang parameter names are not predefined keywords, you can pick almost any parameter names you like.
They aren't in q either: x can be redefined to whatever you like.
How does KatLang determine which argument is first? Is it merely the first free variable?
Yes, the first unknown identifier becomes the first parameter, next unknown identifier becomes next parameter and so on...
rabarbers commented on Show HN: KatLang – Language for Calculations katlang.org/... · Posted by u/rabarbers
> Your OCaml function example looks like feature I call conditional parameters in KatLang (inspired from Erlang).
It does! Elixir (coming from Erlang) and Haskell have the same thing, both through pattern matching of a function to different definitions. OCaml (and most other languages using pattern matching) pattern match inside a single definition.
> In mathematics exists many different concepts which are called perfect. For example, perfect numbers.
I personally only know about perfect numbers. I'm not sure if it's a great name for them, or if it's just a "fun" name like sexy prime https://en.wikipedia.org/wiki/Sexy_prime that doesn't mean much.
For your example about the identity function, I think it's great, but I'm personally more in favour of positional lambdas like &1 in Elixir.
> The question is: can you remove one more symbol without changing the meaning of the expression? If no, then, the identity function definition 'x' is symbols perfect according to my definition.
Maybe "minimal" would be a better name then? Or "shortest"? Many people could argue on what makes the perfect lambda, but it's hard to argue that yours isn't the most minimal or shortest.
Probably picking the term "perfect" was not the best think I could do. Seems, that others actively fight against it. I still believe that the perfect syntax has both attributes: 1) it is the shortest 2) it is expressive - you can express any expression in it. Picking that name made my life much more difficult.