[munchler]

Well, I totally disagree with this. One of the main benefits of currying is the ability to chain function calls together. For example, in F# this is typically done with the |> operator:

    let result =
        input
            |> foobinade a b
            |> barbalyze c d

Or, if we really want to name our partial function before applying it, we can use the >> operator instead:

    let f = foobinade a b >> barbalyze c d
    let result = f input

Requiring an explicit "hole" for this defeats the purpose:

    let f = barbalyze(c, d, foobinade(a, b, $))
    let result = f(input)

Or, just as bad, you could give up on partial function application entirely and go with:

    let result = barbalyze(c, d, foobinade(a, b, input))

Either way, I hope that gives everyone the same "ick" it gives me.

[emih]

You can still do this though:

  let result = (barbalyze(c, d, $) . foobinade(a, b, $)) input

Or if you prefer left-to-right:

  let result = input
    |> foobinade(a, b, $)
    |> barbalyze(c, d, $)

Maybe what isn't clear is that this hole operator would bind to the innermost function call, not the whole statement.

[twic]

Even better, this method lets you pipeline into a parameter which isn't the last one:

  let result = input
    |> add_prefix_and_suffix("They said '", $, "'!")

[raincole]

Yeah, especially in F#, a language that means to interpolate with .Net libraries (most not written with "data input at last" mindset.) now I'm quite surprised that F# doesn't have this feature.

[raincole]

Wow, this convinced me. It's so obviously the right approach when you put it this way.

[Smaug123]

This is essentially how Mathematica does it: the sugar `Foo[x,#,z]&` is semantically the same as `Function[{y}, Foo[x,y,z]]`. The `&` syntax essentially controls what hole belongs where.

[skybrian]

For pipelines in any language, putting one function call per line often works well. Naming the variables can help readability. It also makes using a debugger easier:

  let foos = foobinate(a, b, input)
  let bars = barbakize(c, d, foos)

Other languages have method call syntax, which allows some chaining in a way that works well with autocomplete.

[RHSeeger]

> Naming the variables can help readability

It can, or it can't; depending on the situation. Sometimes it just adds weight to the mental model (because now there's another variable in scope).

[skybrian]

Sure, I like chained method calls too, for simple things. But it gets ridiculous sometimes where people write a ten-stage pipeline in a single expression and then call that "readable."

[RHSeeger]

I'm with you 100%. The main thing is that sometimes a "break point" (using a variable rather than _more_ chain) can help readability. And sometimes it makes things worse. It's really a case-by-case type of thing.