PowerShell HashTable - self referencing during initialization - powershell

Question

I have a theoretical problem - how to reference a hash table during its initialization, for example, to compute a member based other already stated members.
Remove-Variable myHashTable -ErrorAction Ignore
$myHashTable =
#{
One = 1
Two= 2
Three = ??? # following expressions do not work
# $This.One + $This.Two or
# $_.One + $_.Two
# $myHashTable.One + $myHashTable.Two
# ????
}
$myHashTable.Three -eq 3 # make this $true
Any ideas how to do it? Is it actually possible?
Edit:
This was my solution:
$myHashTable =
#{
One = 1
Two= 2
}
$myHashTable.Three = $myHashTable.One + $myHashTable.Two

Answer 1

This won't be possible using the object initializer syntax I'm afraid. While it is possible to use variables, you'll have to compute the values before creating the object.

Answer 2

I cannot recommend this, but you can iterate the initializer twice or more:
(0..1) | %{
$a = #{
One = 1
Two = $a.One + 1
}
}
(0..2) | %{
$b = #{
One = 1
Two = $b.One + 1
Three = $b.Two + 1
}
}
Make sure all calculations are idempotent, i.e. do not depend on a number of iterations.

Answer 3

You can also recur to this...
sometimes when the hashtable is very long
and can be defined only in 2 or three recurrences...
works fine:
$AAA = #{
DAT = "C:\MyFolderOfDats"
EXE = "C:\MyFolderOfExes"
}
$AAA += #{
Data = $AAA.DAT + "\#Links"
Scripts = $AAA.EXE + "\#Scripts"
ScriptsX = $AAA.EXE + "\#ScriptsX"
}
Note in the second part we are just adding ( += ) more items to the first part... but now... we can refer the items in first part
of the hashtable