Nix Language

Nix expression: a piece of code evaluated that produce a nix value
A nix file is a nix expression
We can evaluate nix expression using nix repl
To exit nix repl you can press :q
Break lines, indentation, spaces is only to the code be more readable
Nix Function only has one argument and are separated by :
Functions Libraries are the standard libraries of language, containing pkgs.lib, builtins and import
The only impurities on the language are the Build Inputs, that are composed of file system.
Nix reference files using the content hash. If It does not know its content, it read the file during the evaluation of the derivations
[eaf9g-nix-let-in]]# are expression on on language that access variable inside itself, or a way to assign variable recursively
There is something similar to Nix: let…in is the Attribute Set with rec propriety. The variable can be used in the same scope it was defined.
Nix language can use variables on the code using String Interpolation. It is possible to escape them to no make confuse with bash variables.
Inherit is a way to assign variable on a nested scope.

nix-repl > 1+2
3
nix-repl > { a.b.c = 1; }
{ a = {...}; }
nix-repl > :p { a.b.c = 1;}
{ a = { b = {c 1;};};}

To evaluate one nix file:

$ echo 1+2 > default.nix
$ nix-instantiate --eval
3