To broaden my knowledge of nix, I’m working through an Overview of the Nix Language.
Most of the data types and structures are relatively self-explanatory in the context of modern programming languages.
Double single quotes strip leading spaces.
'' s '' == "s "
Functions are a bit unexpected visually, but simply enough with an accompanying explanation.
For example, the following is a named function f with two arguments x and y.
f = x: y: x*y
To call the function, write f 1 4.
Calling the function with only a single arg returns a partial.
f 3
# returns `y: 3*y`
The with statement introduces values the scope of the expression so, you don’t need to use the dot notation.
let
set = { a = 4; b = 10; };
in
with set; "The values are ${toString a} and ${toString b}"
Values defined in a with statement do not override already defined values with the same name.
The rec expression turns a basic set into a set where self-referencing is possible.
rec {
val1 = val2 + 100;
val2 = 12;
}.val1
# outputs 112
nix repl can be used to test out statements in the Nix language.