param (
    [parameter( Mandatory = $true, HelpMessage = "Enter an integer between 0 and 255", ValueFromPipeline = $true )]
    [ValidateScript({
        try {
            # Check if an integer was specified
            if ( [int32]::TryParse( $_, [ref]0 ) ) {
                # Check if the integer is within the allowed range
                if ( ( [int]$_ -ge 0 ) -and ( [int]$_ -le 255 ) ) {
                    # Return just the result, without newline
                    Write-Host ( [char][int]$_ ) -NoNewline
                }
            }
        }
        catch { }
        # Always return true so we can use our custom error handling
        $true
    })]
    [object]$charnum,
    [parameter(ValueFromRemainingArguments=$true)]
    [object]$ignored
)


# Repeat the test of the input, so we can show the appropriate error message
$rc = 1
if ( $charnum -ne "/?" ) {
    if ( [int32]::TryParse( $charnum, [ref]0 ) ) {
        if ( ( [int]$charnum -ge 0 ) -and ( [int]$charnum -le 255 ) ) {
            $rc = 0
        } else {
            Write-Host "`nError: " -ForegroundColor Red -NoNewline
            Write-Host "Specified integer should be in range 0..255`n" -ForegroundColor White
        }
    } else {
        Write-Host "`nError: " -ForegroundColor Red -NoNewline
        Write-Host "Please specify an " -NoNewline
        Write-Host "integer " -ForegroundColor White -NoNewline
        Write-Host "between 0 and 255`n"
    }
}

if ( $rc -ne 0 ) {
    Write-Host
    Write-Host "Chr.ps1,  Version 1.01"
    Write-Host "Returns the ASCII character for the specified numeric value"
    Write-Host
    Write-Host "Usage:   " -NoNewline
    Write-Host "CHR.PS1  number" -ForegroundColor White
    Write-Host
    Write-Host "Returns: ASCII character for specified " -NoNewline
    Write-Host "number" -ForegroundColor White -NoNewline
    Write-Host " (0..255)"
    Write-Host
    Write-Host "Notes:   The ASCII character is written to Standard Output (i.e. the screen)."
    Write-Host "         The script will prompt for input if command line argument is missing."
    Write-Host "         Piped input is accepted; if multiple arguments are piped, all will"
    Write-Host "         be handled; if multiple arguments are passed on the command line,"
    Write-Host "         however, the script will ignore all but the first argument."
    Write-Host "         The `"errorlevel`" is 1 in case of errors, otherwise 0."
    Write-Host
    Write-Host "Written by Rob van der Woude"
    Write-Host "http://www.robvanderwoude.com"
}

Exit $rc