diff options
Diffstat (limited to 'tvix/serde/examples')
-rw-r--r-- | tvix/serde/examples/cfg-demo.rs | 35 | ||||
-rw-r--r-- | tvix/serde/examples/foods.nix | 22 | ||||
-rw-r--r-- | tvix/serde/examples/nixpkgs.rs | 34 |
3 files changed, 91 insertions, 0 deletions
diff --git a/tvix/serde/examples/cfg-demo.rs b/tvix/serde/examples/cfg-demo.rs new file mode 100644 index 0000000000..5774a81f77 --- /dev/null +++ b/tvix/serde/examples/cfg-demo.rs @@ -0,0 +1,35 @@ +//! This program demonstrates how to use tvix_serde to deserialise +//! program configuration (or other data) from Nix code. +//! +//! This makes it possible to use Nix as an embedded config language. +//! For greater control over evaluation, and for features like adding +//! additional builtins, depending directly on tvix_eval would be +//! required. +use serde::Deserialize; +use std::collections::HashMap; + +#[derive(Debug, Deserialize)] +enum Flavour { + Tasty, + Okay, + Eww, +} + +#[allow(dead_code)] +#[derive(Debug, Deserialize)] +struct Data { + name: String, + foods: HashMap<String, Flavour>, +} + +fn main() { + // Get the content from wherever, read it from a file, receive it + // over the network - whatever floats your boat! We'll include it + // as a string. + let code = include_str!("foods.nix"); + + // Now you can use tvix_serde to deserialise the struct: + let foods: Data = tvix_serde::from_str(code).expect("deserialisation should succeed"); + + println!("These are the foods:\n{:#?}", foods); +} diff --git a/tvix/serde/examples/foods.nix b/tvix/serde/examples/foods.nix new file mode 100644 index 0000000000..c8733cd3ef --- /dev/null +++ b/tvix/serde/examples/foods.nix @@ -0,0 +1,22 @@ +# This is content for the `Data` struct, written in intentionally +# convoluted Nix code. +let + mkFlavour = flavour: name: { + inherit name; + value = flavour; + }; + + tasty = mkFlavour "Tasty"; + okay = mkFlavour "Okay"; + eww = mkFlavour "Eww"; +in +{ + name = "exhaustive list of foods"; + + foods = builtins.listToAttrs [ + (tasty "beef") + (okay "tomatoes") + (eww "olives") + (tasty "coffee") + ]; +} diff --git a/tvix/serde/examples/nixpkgs.rs b/tvix/serde/examples/nixpkgs.rs new file mode 100644 index 0000000000..ad8c4160b5 --- /dev/null +++ b/tvix/serde/examples/nixpkgs.rs @@ -0,0 +1,34 @@ +//! This program demonstrates deserialising some configuration +//! structure from Nix code that makes use of nixpkgs.lib +//! +//! This example does not add the full set of Nix features (i.e. +//! builds & derivations). + +use serde::Deserialize; + +#[derive(Debug, Deserialize)] +struct Config { + host: String, + port: usize, +} + +fn main() { + let code = r#" + let + lib = import <nixpkgs/lib>; + host = lib.strings.concatStringsSep "." ["foo" "example" "com"]; + in { + inherit host; + port = 4242; + } + "#; + + let result = tvix_serde::from_str_with_config::<Config, _>(code, |eval| { + eval.enable_impure(None); + }); + + match result { + Ok(cfg) => println!("Config says: {}:{}", cfg.host, cfg.port), + Err(e) => eprintln!("{:?} / {}", e, e), + } +} |