Constants and variables

Constants can be defined under the heading const. The Pipefish style guide recommends that you use SCREAMING_SNAKE_CASE to name them.

Variables can be declared under the heading var.

An example is given in examples/wiki/variables.pf

Constants and the initial values of variables can be computed at compile time, as x is in the example above.

You can change the values of variables via the REPL, but you can't create them: they must be declared in the script.

Constants are in scope for all commands and functions. Variables can only be seen by commands, and even then you must bring them into the scope of the command using the global keyword. E.g if we add this to the script above, it will do what you think it would do.

In Pipefish, variables by default take on the type of the thing assigned to them on declaration. So x is of type int, and h is of type string, and trying to store anything else in them causes an error. This is only the default behavior — Pipefish is after all a dynamic language! We'll come back to this when we look at the type system.