Making Regex's readable using 'x' or .VERBOSE flags

Making Regular expressions readable.md

Making regular expressions readable

What is easier to understand two months from now? Note that they are exactly equal in this example.

$regex = '(?n)(?<destination>(\d{1,3}\.){3}\d{1,3}).*time=(?<ms>\d+)ms'

verses

$regex = '(?xn)    
    # You can use in-line comments!

    # ip group:
    (?<destination>
        (
            \d{1,3}\.
        ){3}
        \d{1,3}
    )

    .*
    # Ping as Milliseconds
    time= 
    (?<ms>
        \d+    
    )
    ms
'

See more:

• CSharp example [https://mariusschulz.com/blog/practical-use-cases-for-the-regexoptions-flags#regexoptions-ignorepatternwhitespace]
• Python's flag .X or .VERBOSE
• Dotnet, powershell, c# flag for IgnorePatternWhitespace1
• Regex101.com supports ignore whitespace

Making Regular expressions readable.png

Making Regular2 - Select-String verses Grep or RipGrep.png

readable_regex_using_powershell.ps1

$cached = ping google.com
'Input: ', $cached

# the only change between these is the second adds the flag 'x'
# they are the exact same pattern
$regex_basic = '(?n)(?<destination>(\d{1,3}\.){3}\d{1,3}).*time=(?<ms>\d+)ms'
$regex_readable = '(?xn)
    # You can use in-line comments!

    # ip group:
    (?<destination>
        (
            \d{1,3}\.
        ){3}
        \d{1,3}
    )

    .*
    # ping ms
    time=
    (?<ms>
        \d+
    )
    ms'

"`n`$regex_basic:`n"

$results_basic = $cached | ForEach-Object {
    Write-Debug "line: $_"
    if ($_ -match $regex_basic ) {
        # 'n' removed non-named capture groups
        # then manually remove the full capture group: 0
        $matches.Remove(0)
        [pscustomobject]$matches
    }
}
$results_basic | Format-Table

"`n`$regex_readable:`n"

$results_x = $cached | ForEach-Object {
    Write-Debug "line: $_"
    if ($_ -match $regex_readable ) {
        $matches.Remove(0)
        [pscustomobject]$matches
    }
}
$results_x | Format-Table

# filter fast pings
$results_x | Where-Object Ms -GT 25 | ConvertTo-Json