Crosscut

Except for the erroneous concatenation of two integer literals from yesterday, we've only seen expressions that consist of a single syntax node. Let's look into some more complex, but still valid, expressions today.

64 halve

Here, we're using a halve function that takes an integer as input and returns another integer (divided by two) as output. Such a function currently doesn't exist in Crosscut, but a host could easily define it.

I've talked about the active value before. Here, the active value at the beginning of the expression is nothing (of type Nothing). After the 64, it's 64 (of type Integer). After the halve, it's 32 (still of type Integer).

We can build more complex expressions, by chaining more function applications of the appropriate type:

64 halve halve double double

In this one, if the double function does what its name suggests and multiplies by two, we end up with 64 again.