Friday, November 23, 2007

PowerShell DSLs: Script block input

As an alternative to using a hashtable for input, you can use a script block. Here's a script-block-way of doing the same thing as before:

class MyClass -accessibilty:public {

member string S

}


and here's one of many ways of handling it

function class {

param (

[String] $name = $( throw
"name is required" ),

[String] $accessibilty,

[ScriptBlock] $memberScriptBlock = $( throw
"member script block is require" )

)


" $accessibilty class $name {"


& $memberScriptBlock % { " public $($_.declaration)" }


" }"

}


function member {

param (

[String] $type = $( throw
"type is required" ),

[String] $name = $( throw
"name is required" )

)


@{

declaration = "$type $name;"


}

}


What's happening here is that the first word on any line becomes a function, and the remaining words are parameters to that function. So, you're now creating an "internal DSL" in PowerShell. This lets you work in a more idoimatic PowerShell manner.


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