PipeScript

Almost any given sentence could be considered valid PowerShell (including this one).

What if we could parse a command as a sentence?

How?

One could map a sentence to a command in a natural language syntax.

This can be done by:

• Walking over the [AST]
• Treating a [CommandParameter]s normally, and consider them the start of a clause
• Any bareword that is a parameter name/alias (or /parameter or –parameter) will mark the start of a clause
• Any arguments between two parameters will be considered part of the same clause
• If a command has a parameter with ValueFromRemainingArguments, unbound parameters will be bound to it
• Otherwise, they will be returned in their own clause

So algorithmically, this is pretty straightforward.

Why?

If you treated a commands a sentences, instead of the way it would normally be parsed in PowerShell, it looks shorter and reads more naturally:

For Example, here are some alternative ways to write Get-Process:

Get-Process -Name powershell -IncludeUserName

Get-Process Name powershell IncludeUserName pwsh
Get-Process IncludeUserName Name powershell pwsh
Get-Process /IncludeUserName --Name powershell pwsh

In the trio of examples, there should be two clauses in the sentence, Name PowerShell and IncludeUserName

PipeScript Keywords and Natural Syntax

One of the pain points with writing a PipeScript keyword has been how to structure it’s arguments. Because keywords are parsing a CommandAST that has not run, even if one defined parameters on the keyword, they wouldn’t be automatically bound.

Thus there has been a need to have a consistent way to “pre-parse” a keyword.

Additionally, there’s been the desire to make PipeScript’s syntax even more high level than PowerShell’s.

Want an example? In the same Pull Request in which Natural Syntax support was introduced, the ‘all’ keyword was introduced.

This leads to the wonderfully natural syntax you see below.

all functions that AsJob    # would get all -Functions -That have an -AsJob parameter

That’s some pretty readable code, right?

Moving forward, expect to see most new keywords using this natural language format.

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