Remove Unused Functions in AutoIt Script with PowerShell - regex

Question

Alrighty..
So I am editing an AutoIt script that has a lot of unused functions in it. The original author saw fit to add all the functions from his/her includes files.
At first I tried to use the tools within AutoIt/SciTe to remove unused functions however for some freakish reason this rendered the script/compiled file useless. So now I am thinking it would be best to write a function remover.
Here is what I have so far:
Search for lines with "Func _" count number of times that function appears in the file. If 1 time then Select String
$FileName=".\FILENAME.au3"
$File=Get-Content $FileName
$Funcs=$File|Select-String "Func _"
foreach ($Func in $Funcs) {
$FuncName=$Func.ToString().Split('( ')[1]
$Count=($File|Select-String $FuncName | Measure-Object).Count
if ($count -eq 1) {
$File|Select-String "Func _" $FuncName
}
}
What I would like to do is remove the function, likely with regex. So something like:
REMOVE "Func _"$func * "EndFunc"
The trouble has been that this is a search that spans multiple lines, from Func _NAMEOFFUCTION to EndFunc. Its unclear to me if regex in PowerShell can even do this. Not all regex implementations seem to be able to span a search across lines. Is regex even the answer? I don't know.

Answer 1

When you use Get-Content in PowerShell 1.0 or 2.0 you can only get back an array of strings - one for each line. This isn't going to work when you need a regex to span multiple lines. Use this approach to read the file as a single string:
$FileContent = [io.file]::ReadAllText($FileName)
If you are on PowerShell V3 you can use the -Raw parameter to read the file as a single string:
$FileContent = Get-Content $FileName -Raw
Then when you use Select-String you will need to modify the regex to enable singleline s (and probably multiline m) mode e.g.:
$FileContent | Select-String "(?smi)$FuncName" -AllMatches
Note the i is there to be case-insensitive. Use the -AllMatches parameter to match multiple function definitions within a file.

Answer 2

Here's a regex that should match an AutoIt function definition. It assumes the Func and EndFunc keywords are always placed at the beginning of a line and that they're case sensitive. The function name is captured in the group named FuncName (in C# you would access it via Groups["FuncName"]);
"(?m)^Func\s+\b(?<FuncName>_\w+\b).*\n(?:(?!EndFunc\b).*\n)*EndFunc.*\n?"
For the function names alone you can use "\b_\w+\b" or maybe "\b_[A-Za-z]+\b"; I don't know how strict you need to be). Having almost zero experience with PowerShell, I would probably use [regex]::Matches and [regex]::Replace to do the work. I don't know if PS offers a better way.
I'm assuming you've read the whole file into a string as #Keith suggested, not line by line as you were doing originally.