Powershell: testing if cli tool is installed

isInstalled.ps1

# Had no success with usual redirecting, so using this instead
# 
# USAGE:
# isInstalled '[command]' '[test]'
#
# e.g. checking whether chocolatey is present
# $test = isInstalled 'choco -v' '^\d+\..*?$'

Function isInstalled([string]$trigger, [string]$match){
    $ErrorActionPreference = "SilentlyContinue";
    $output = iex $trigger;
    $ErrorActionPreference = "Continue";

    return [boolean]($output -match '^\d+\..*?$');
}