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authorDmitrii Kuznetsov <torgeek@users.noreply.github.com>2021-02-22 18:36:35 +0300
committerGitHub <noreply@github.com>2021-02-22 18:36:35 +0300
commitbc8bd2646f068cfb402850f7c0f9b1dbfe81e5a0 (patch)
tree89213fd6afbf9cc9303c1c2fa08dafc840a9d99d /nix.html.markdown
parent363d5281f1e3d5bee6339b5316405b0a4b592c49 (diff)
parent110511a10110f96b20f107c078f7d5ef4c01b109 (diff)
Merge pull request #1 from adambard/master
Merge from original adambard
Diffstat (limited to 'nix.html.markdown')
-rw-r--r--nix.html.markdown45
1 files changed, 34 insertions, 11 deletions
diff --git a/nix.html.markdown b/nix.html.markdown
index ef59a135..dde5dbec 100644
--- a/nix.html.markdown
+++ b/nix.html.markdown
@@ -3,6 +3,8 @@ language: nix
filename: learn.nix
contributors:
- ["Chris Martin", "http://chris-martin.org/"]
+ - ["Rommel Martinez", "https://ebzzry.io"]
+ - ["Javier Candeira", "https://candeira.com/"]
---
Nix is a simple functional language developed for the
@@ -11,7 +13,7 @@ Nix is a simple functional language developed for the
You can evaluate Nix expressions using
[nix-instantiate](https://nixos.org/nix/manual/#sec-nix-instantiate)
-or [`nix-repl`](https://github.com/edolstra/nix-repl).
+or [`nix repl`](https://nixos.org/nix/manual/#ssec-relnotes-2.0).
```
with builtins; [
@@ -38,18 +40,26 @@ with builtins; [
#=> "a"
- # Integers
+ # Integers and Floats
#=========================================
- # Integers are the only numeric type.
+ # There are two numeric types: integers and floats
1 0 42 (-3) # Some integers
+ 123.43 .27e13 # A couple of floats
+
+ # Operations will preserve numeric type
+
(4 + 6 + 12 - 2) # Addition
#=> 20
+ (4 - 2.5)
+ #=> 1.5
(7 / 2) # Division
#=> 3
+ (7 / 2.0)
+ #=> 3.5
# Strings
@@ -208,6 +218,12 @@ with builtins; [
{ a = 1; b = 2; }.a
#=> 1
+ # The ? operator tests whether a key is present in a set.
+ ({ a = 1; b = 2; } ? a)
+ #=> true
+ ({ a = 1; b = 2; } ? c)
+ #=> false
+
# The // operator merges two sets.
({ a = 1; } // { b = 2; })
#=> { a = 1; b = 2; }
@@ -231,13 +247,20 @@ with builtins; [
}.a.c
#=> { d = 2; e = 3; }
- # An attribute's descendants cannot be assigned in this
- # way if the attribute itself has been directly assigned.
+ # Sets are immutable, so you can't redefine an attribute:
+ {
+ a = { b = 1; };
+ a.b = 2;
+ }
+ #=> attribute 'a.b' at (string):3:5 already defined at (string):2:11
+
+ # However, an attribute's set members can also be defined piecewise
+ # way even if the attribute itself has been directly assigned.
{
a = { b = 1; };
a.c = 2;
}
- #=> error: attribute ‘a’ already defined
+ #=> { a = { b = 1; c = 2; }; }
# With
@@ -256,7 +279,7 @@ with builtins; [
#=> 7
# This first line of tutorial starts with "with builtins;"
- # because builtins is a set the contains all of the built-in
+ # because builtins is a set that contains all of the built-in
# functions (length, head, tail, filter, etc.). This saves
# us from having to write, for example, "builtins.length"
# instead of just "length".
@@ -314,8 +337,8 @@ with builtins; [
#=========================================
# Because repeatability of builds is critical to the Nix package
- # manager, in which, functional purity is emphasized in the Nix
- # language. But there are a few impurities.
+ # manager, functional purity is emphasized in the Nix language
+ # used to describe Nix packages. But there are a few impurities.
# You can refer to environment variables.
(getEnv "HOME")
@@ -350,5 +373,5 @@ with builtins; [
* [James Fisher - Nix by example - Part 1: The Nix expression language]
(https://medium.com/@MrJamesFisher/nix-by-example-a0063a1a4c55)
-* [Susan Potter - Nix Cookbook - Nix By Example]
- (http://funops.co/nix-cookbook/nix-by-example/)
+* [Rommel Martinez - A Gentle Introduction to the Nix Family]
+ (https://ebzzry.io/en/nix/#nix)