commandline

A naive echo program which repeats its arguments, optionally uppercase words.

How to Compile

With a minimal Pony installation, in the same directory as this README file run ponyc. You should see content building the necessary packages, which ends with:

...
Generating
 Reachability
 Selector painting
 Data prototypes
 Data types
 Function prototypes
 Functions
 Descriptors
Optimising
Writing ./commandline.o
Linking ./commandline

How to Run

Once commandline has been compiled, in the same directory as this README file run ./commandline Example words to echo. You should see your same message repeated back to you:

$ ./commandline Example words to echo
Example words to echo

We can access a help message by using --help.

$ ./commandline --help
usage: echo [<options>] <words>

A sample echo program

Options:
   -h, --help=false
   -U, --upper=false    Uppercase words

Args:
   <words>    The words to echo

From here we can see that there is an option to uppercase words (-U).

$ ./commandline -U Example words to echo
EXAMPLE WORDS TO ECHO

Program Modifications

Modify the program to have a new option called "lower" which works similar to "upper" except that it uses String.lower() rather than String.upper().

$ ./commandline --lower EXAMPLE WORDS TO ECHO
example words to echo

For further modification, modify the program so that using both options ./commandline --upper --lower ... prints an error then the help message.