Complex named match group RegEx review - regex

Question

From this example string
$logLine = '{header[3]}_Pragmatic Praxis Initialization Log'
I am trying to extract three pieces of data
header as type
3 as an (optional) tab value
everything after that _ as a string
What I have now is
$logLine = '{header[3]}_Pragmatic Praxis Initialization Log'
if ($logLine -match '^\{(?<type>[a-z]+)(?:\[?(?<tab>\d?)\]?)\}_(?<string>.+)$') {
Write-Host "$($matches['type'])"
Write-Host "$($matches['tab'])"
Write-Host "$($matches['string'])"
}
And it's working well. But I am so unskilled in RegEx, and this is by far the most complex RegEx I have ever cobbled together from scratch, that I am wondering if anyone sees a gotcha in this approach that I am not seeing?
Or do I need to open some wine and celebrate reaching some sort of RegEx comprehension milestone?
EDIT:
So my success made me over confident. I decided to make Tab required, but add an optional Target which can be either 'console' or 'file'. So I did this
$logLine = '{header[3]}_Pragmatic Praxis Initialization Log'
if ($logLine -match '^\{(?<type>[a-z]+)(?:-(?<target>(console|file)))\[(?<tab>\d*)\]\}_(?<string>.+)$') {
Write-Host "$($matches['type'])"
Write-Host "$($matches['target'])"
Write-Host "$($matches['tab'])"
Write-Host "$($matches['string'])"
}
Which works a treat when target is present, but fails when it is not. So, looks like I get to learn something, rather than celebrate. ;)
EDIT #2:
Per #Ansgar Wiechers, I was indeed misunderstanding (?:...), specifically confusing it for (....)?. based on that, this is my revised pattern, which seems to be doing what I want. I may still make both target and tab required, since I think it makes the code more readable while also simplifying the RegEx pattern, but still good to have it working as I initially intended it to work too.
if ($logLine -match '^\{(?<type>[a-z]+)(-(?<target>(console|file)))?(\[(?<tab>\d+)\])?\}_(?<string>.+)') {
Write-Host "$($matches['type'])"
Write-Host "$($matches['target'])"
Write-Host "$($matches['tab'])"
Write-Host "$($matches['string'])"
}

Answer 1

Looks to me like you're misunderstanding what (?:...) does. That construct does not define an optional match, but a non-capturing group. A (sub)expression (?:-(?<target>console|file)) will require the string to contain either -console or -file and return console or file (without the leading hyphen) as a named match "target". To make the group optional you need to add another ? after the group.
^\{(?<type>[a-z]+)(?:-(?<target>console|file))?\[(?<tab>\d*)\]\}_(?<string>.+)
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
Note that a trailing expression .+ or .* makes anchoring the expression at the end of the string ($) pointless, so just remove the $ from the end of your expression.
You also don't need the nested (unnamed) capturing group around console|file. The named capturing group is sufficient.