.about Script for various projection-related functions
.pragma main swap

1 define: piggyback_1
            [Pairs up x with 1: <x.1>]
            pair id k_1

2 define: k_1_1
            [The constant <1.1> function]
            pair k_1 k_1

3 define: k_0
            [The constant 0 function]
            comp diff k_1_1

4 define: piggyback_0
            [Pairs up x with 0: <x.0>]
            pair id k_0

5 define: pr_L
            [The left projection function]
            comp proj piggyback_0

6 define: pr_R
            [The right projection function]
            comp s_tup piggyback_1

7 define: swap
            [From <x.y> to <y.x>]
            pair pr_R pr_L

8 define: swap_diff
            [diff(<y.x>)]
            comp diff swap