execParser with specified command-line arguments

[jml]

Related to #100

I have a command-line tool which allows users to specify a default subcommand in their configuration file. To make this work I need to have a function that goes from Config -> CommandLineOptions -> Command

What I'd like to have in optparse-applicative is a helper that looks something like:

execParserWithArgs :: ParserInfo a -> [String] -> IO a
execParserWithArgs opts args =
  handleParseResult $ execParserPure (prefs idm) opts args

That lets me specify command-line options manually.

[pcapriotti]

What is the problem with defining execParserWithArgs within your program? I'm hesitant to add a convenience function to the API for every possible way of running a parser. I actually think there are too many already.

[jml]

Nothing really. I thought that since there are so many, one more wouldn't hurt.