7.1 Poke Scripts

In interactive usage, there are two main ways to execute Poke code: at the interactive prompt (or REPL), and loading “pickles”.

Executing Poke code at the REPL is as easy as introducing a statement or expression:

(poke) print "Hello\n"
Hello

Executing Poke code in a pickle is performed by loading the file containing the code:

(poke) .load say-hello.pk
Hello

Where say-hello.pk contains simply:

print "Hello\n";

However, we would like to have Poke scripts, i.e. to be able to execute Poke programs as standalone programs, from the shell. In other words, we want to use GNU poke as an interpreter. This is achieved by using a shebang, which should appear at the top of the script file. The poke shebang looks like this:

#!/usr/bin/poke -L
!#

The -L command line option tells poke that it is being used as an interpreter. Additional arguments for poke can be specified before -L (but not after). The #! ... !# is an alternative syntax for multi-line comments, which allows to have the shebang at the top of a Poke program without causing a syntax error. This nice trick has been borrowed from guile.

Therefore, we could write say-hello as a Poke script like this:

#!/usr/bin/poke -L
!#

print "Hello\n";

And then execute it like any other program or script:

$ ./say-hello