command_line.md

Running Pepper3

Everything you do with Pepper3 is done by using the pepper3 executable.

The most important subcommands you can type are:

pepper3 run FILENAME
pepper3 compile FILENAME
pepper3 eval EXPRESSION

These are explained in the following sections.

If you want to start an interactive session, simply type:

pepper3

Running a program

To run a program type pepper3 run:

#(Not implemented) $ pepper3 run myprogram.pepper3
Hello from my program!

Or, because run is the default, you can miss it out:

#(Not implemented) $ pepper3 myprogram.pepper3
Hello from my program!

Evaluating programs on the command line

You can evaluate a snippet of code using pepper3 eval:

$ pepper3 eval "x = 3; x"
3

To provide a program to run on stdin, give "-" as the file name.

$ echo "1 + 2" | pepper3 run -
3

Compiling a program

#(Not implemented) $ pepper3 compile myprogram.pepper && ./myprogram
Hello from my program!

Running multiple commands

You can run multiple Pepper3 subcommands in the same environment by joining them together with --. For example, to evaluate a command in the context of come code in a file, you can run the file, then eval the command:

$ cat snippets/set_x_to_4.pepper3
x = 4

$ pepper3 run snippets/set_x_to_4.pepper3 -- eval "x - 1"
3

Echo and Cat

Mainly to facilitate testing of argument and stream handling, Pepper3 includes two subcommands, echo and cat that are very simple versions of the Unix commands with the same names:

$ pepper3 echo Just print my arguments
Just print my arguments

$ echo "Some input" | pepper3 cat
Some input