Documentation

Computation getArgs returns a list of the program's command line arguments (not including the program name).

Computation getProgName returns the name of the program as it was invoked.

However, this is hard-to-impossible to implement on some non-Unix OSes, so instead, for maximum portability, we just return the leafname of the program as invoked. Even then there are some differences between platforms: on Windows, for example, a program invoked as foo is probably really FOO.EXE, and that is what getProgName will return.

Computation getEnv var returns the value of the environment variable var.

This computation may fail with:

• System.IO.Error.isDoesNotExistError if the environment variable does not exist.

withArgs args act - while executing action act, have getArgs return args.

withProgName name act - while executing action act, have getProgName return name.

getEnvironment retrieves the entire environment as a list of (key,value) pairs.

If an environment entry does not contain an '=' character, the key is the whole entry and the value is the empty string.