All of these languages are relatively succinct, and I rely on that to reduce visual and mental clutter, because I have a pea brain.

Factor, Nim, Roc, and Zsh each offer, to differing extents, some argument-then-function ordering in the syntax, which strikes me as elegant and fun, and maybe even wise. In that order, Factor does this the most (using postfix/reverse-polish-notation and managing a data stack), and Zsh the least (piping output from one command as the input for the next command).

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Roc

Roc is a functional language, and an offshoot of Elm in spirit. The lead developer and community are great. Relative to Elm, it’s more inclusive and experimental in the development process, and does not primarily or exclusively target web stuff. They aim to create an ambitiously integrated development environment, especially taking advantage of any guarantees the functional design can offer.

Here’s a sample, using the |> operator a lot, which lets you order the first argument to a function before the function IIRC:

getData = \filepath ->
    filepath
    |> Path.fromStr
    |> File.readUtf8
    |> Task.attempt \result ->
        result
        |> Result.withDefault ""
        |> Task.succeed

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Nim

Nim is so darn flexible and concise, has great compilation targets, and employs Uniform Function Call Syntax to more implicitly enable the kind of ordering in the Roc example. And you can often leave out parentheses entirely.

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Factor

Factor is a full-on postfix and concatenative language, tons of fun, and turns my brain inside out a bit. I made a community for concatenative languages here on programming.dev, and while there’s little activity so far, I’ve filled the sidebar with a bunch of great resources, including links to active chats.

EDIT: !concatenative@programming.dev

The Factor REPL (“listener”) provides excellent and speedy documentation and definitions, and a step-through debugger.

One idea that seems absurd at first is that for the most part, you don’t name data variables (though you can, and you do name function parameters). It’s all about whatever’s on the top of the stack.

In some languages it’s awkward to approximate multiple return values, but in a stack-oriented language it’s natural.

In Factor, everything is space-separated, so functions (“words”) can and do include or consist of symbols. [1..b] is not semantically something between brackets, it’s just a function that happens to be named [1..b]. It pops 1 item off the top of the stack (an integer), and pushes a range from 1 to that integer on to the top of the stack.

Here it is in my solution to the code.golf flavor of Fizz Buzz:

USING: io kernel math.functions math.parser ranges sequences ;

100 [1..b] [ 
  dup [ 3 divisor? ] [ 5 divisor? ] bi 2dup or [ 
    [ drop ] 2dip 
    [ "Fizz" "" ? ] [ "Buzz" "" ? ] bi* append 
  ] [ 2drop number>string ] if
  print 
] each

And in image form for glorious syntax highlighting:

Factor example walkthrough

Anything between spaced brackets is a “quotation” (lambda/anonymous function).

So:

• Push a range from 1-100 onto the stack.
• Push a big quotation that doesn’t end till each at the bottom.
• each consumes the range and the quotation. For each element of the range, it pushes the element then calls the quotation.
• dup pushes a copy of the stack’s top item. Say we’re in the ninth iteration of the each loop, we’ve got 9 9 on the stack.
• Two quotations are pushed (9 9 [...] [...]), then bi applies them each in turn to the single stack item directly beneath, leaving us with 9 t f (true, it’s divisble by three, false, it’s not by 5).
• 2dup copies the top two, so: 9 t f t f
• or combines the last two booleans: 9 t f t
• Two quotes are pushed, followed by an if (9 t f t [...] [...] if), which pops that final t and calls only the first quotation.
• [ drop ] 2dip takes us from 9 t f to t f – it dips under the top two, drops the temporary new top, then restores the original top two.
• ? is like a ternary. That first quotation will push "Fizz" if called with t (true) on the stack, "" otherwise.
• bi* applies the last two items (quotations) to the two values before them, each only taking one value. The Fizz one applies to t and the Buzz to f, taking us from t f [...] [...] to "Fizz" ""
• append joins those strings, as it would any sequence: "Fizz"
• Finally we print the string, leaving us with an empty stack, ready for the next iteration.

EDIT: Walkthrough in image form, more granular: