[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.