Pipe expressions

A pipe expression allows some parenthesis to be omitted by expressing sequences of command executions as a pipeline. It has two forms, and they may not be mixed.

Self pipe

The self pipe (|) allows the result of a previous expression to be passed as the self parameter to another command. It has the following syntax:

Some-expression
  | some-command: Args may: Go here: Too
  | more-commands
  | yet-more-commands: Go-here

Only a single postfix or a single keyword command is allowed after the pipe. And the above is roughly equivalent to the following:

let A = Some-expression;
let B = A some-command: Args may: Go here: Too;
let C = B more-commands;
let D = C yet-more-commands: Go-here;

Generic pipe

The generic pipe (|>) allows the result of a previous expression to be provided to an unary delayed program. It has the following syntax:

Some-expression
  |> _ some-command: Args may: Go here: Too
  |> { A in A more-commands }
  |> yet-more-commands: _;

The expression to the right of a generic pipe should always be a delayed program that takes one argument. The above is roughly equivalent to the following:

let A = Some-expression;
let B = (_ some-command: Args may: Go here: Too)(A);
let C = ({ A in A more-commands })(B);
let D = (yet-more-commands: _)(C);