blob: 1b2dd5b96e2b14ad80cab460167145f54b2f448e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
# Function References
Limbo supports references to functions, similar to closures, but more similar to function pointers.
The example in this section is a derivative of the function reference summary in the [Limbo Addendum](http://www.vitanuova.com/inferno/papers/addendum.pdf).
## Source
### funcrefs.b:18,34
The variable `fp` is a name whose type is a reference to a function with a given argument and return value scheme. A function which fulfills this scheme can be used to set the reference, in this case the `cmp()` function is referenced by `fp`.
### funcrefs.b:36,46
The `sort()` function takes a function reference as an argument, using it as a comparator. In this case `cmp()` and `rcmp()` are passed as a function reference argument.
### funcrefs.b:48,53
The `choose()` function returns a reference to a function, being called in this case to return a given comparator with the comparator being called in-line.
## Demo
; limbo funcrefs.b
; funcrefs
Matched smiley!
Did not match duck
[ d b c a]
[ a b c d]
[ d c b a]
quack ≥ quack
;
## Exercises
- Change the value of `c` to 1, what happens?
- Write a function which returns a function which returns a function.
|
