Process module:System -package:unix -package:Win32 package:cmdargs

Process a list of flags (usually obtained from getArgs/expandArgsAt) with a mode. Returns Left and an error message if the command line fails to parse, or Right and the associated value.
Process the flags obtained by getArgs and expandArgsAt with a mode. Displays an error and exits with failure if the command line fails to parse, or returns the associated value. Implemented in terms of process. This function makes use of the following environment variables:
  • $CMDARGS_COMPLETE - causes the program to produce completions using complete, then exit. Completions are based on the result of getArgs, the index of the current argument is taken from $CMDARGS_COMPLETE (set it to - to complete the last argument), and the index within that argument is taken from $CMDARGS_COMPLETE_POS (if set).
  • $CMDARGS_HELPER/$CMDARGS_HELPER_PROG - uses the helper mechanism for entering command line programs as described in System.Console.CmdArgs.Helper.
Process a list of flags (usually obtained from getArgs and expandArgsAt) with a mode. Throws an error if the command line fails to parse, or returns the associated value. Implemeneted in terms of process. This function does not take account of any environment variables that may be set (see processArgs). If you are in IO you will probably get a better user experience by calling processValueIO.
Like processValue but on failure prints to stderr and exits the program.