Elm Language Functions and Partial Application Local variables
Example
It is possible to define local variables inside a function to
- reduce code repetition
- give name to subexpressions
- reduce the amount of passed arguments.
The construct for this is let ... in ....
bigNumbers =
let
allNumbers =
[1..100]
isBig number =
number > 95
in
List.filter isBig allNumbers
> bigNumbers
[96,97,98,99,100] : List number
> allNumbers
-- error, doesn't know what allNumbers is!
The order of definitions in the first part of let doesn't matter!
outOfOrder =
let
x =
y + 1 -- the compiler can handle this
y =
100
in
x + y
> outOfOrder
201 : number
