Arrow Operators
[# Currently borken! # # a -> a + 1 # incrementor # # (a, b) -> a + b # adder # # users.each( # u -> "<b>$u.surname</b>, $u.forename" # ) # # users.sort( # (a, b) -> a.surname cmp b.surname # ) #] --EOF--look inside...
Thus Spake Andy:
Thin arrows provide a lightweight syntax for creating simple functions
(lambda functions for those in the know). The first example creates an
incrementing function that takes an a and returns a + 1. The
second example takes an a and a b and returns their sum. The third
example passes a function to the each list virtual method that we call
for a list of users. The function is called once for each user in the list,
passed to the function as u. The function formats the user's name as HTML
and returns it. The fourth example shows how a list can be sorted by
providing a comparison function.
TT2 offered a number of different virtual data methods for doing different kinds of sort, etc. TT3 provides a couple of basic ones that accept functions as arguments and provides you with the syntax to create functions. This gives you more flexibility/power and makes the underlying implementation (and concept) that little bit simpler.
Alas, I broke the arrow operator last week (before I wrote these slides). One side-effect of using TT3 to syntax highlight the examples is that it refuses to parse code that is broken - so I had to comment it out just to be able to show you the example! This should be working again Real Soon Now.