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Nix Language Basics

  • NOTE: Everything is an expression in nix Language
  • NOTE: Values in Nix are immutable

Types in Nix​

  • Integer
  • Floating point
  • String
  • Path
  • Boolean

Identifier naming​

  • Common language naming convention is applied
  • Additionally "-" can be used for naming
nix-repl> hello-world = "hello world"

String​

  • String literals can be defined using "string" or ''string''
  • Nix expressions can be interpolated within strings using ${} syntax

Ex:-

nix-repl> name = "Srinesh"
nix-repl> welcome-message = "Welcome ${name}"
nix-repl> welcome-message
# "Welcome Srinesh"

Ex:-

nix-repl> result = 60
nix-repl> "You are ${if result < 50 then "fail" else "pass"}"
# "You are passed"

Escaping ${...}​

  • When using "", ${} can be escaped with \
  • when using '''', ${} can be escaped with ''

Ex:-

nix-repl> name = "Srinesh"
nix-repl> "${name}"
# Srinesh
nix-repl> "\${name}"
# ${name}

nix-repl> ''${name}''
# Srinesh
nix-repl> ''''${name}''
# ${name}

Lists​

NOTE: Adding and removing from a list is possible but will return a new list since everything is mutable in nix.

  • Lists can be defined withing square brackets
  • List items are separated by space

Ex:-

nix-repl> [1 "hello" /home]
# [1 "hello" /home]

Attribute Set​

s = { foo = "bar"; a-b = "baz"; "123" = "num"; }