dfe137786c
Make constructing of a new Evaluation use the builder pattern rather than setting public mutable fields. This is currently a pure refactor (no functionality has changed) but has a few advantages: - We've encapsulated the internals of the fields in Evaluation, meaning we can change them without too much breakage of clients - We have type safety that prevents us from ever changing the fields of an Evaluation after it's built (which matters more in a world where we reuse Evaluations). More importantly, this paves the road for doing different things with the construction of an Evaluation - notably, sharing certain things like the GlobalsMap across subsequent evaluations in eg the REPL. Fixes: b/262 Change-Id: I4a27116faac14cdd144fc7c992d14ae095a1aca4 Reviewed-on: https://cl.tvl.fyi/c/depot/+/11956 Tested-by: BuildkiteCI Autosubmit: aspen <root@gws.fyi> Reviewed-by: flokli <flokli@flokli.de>
34 lines
818 B
Rust
34 lines
818 B
Rust
//! This program demonstrates deserialising some configuration
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//! structure from Nix code that makes use of nixpkgs.lib
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//!
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//! This example does not add the full set of Nix features (i.e.
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//! builds & derivations).
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use serde::Deserialize;
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#[derive(Debug, Deserialize)]
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struct Config {
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host: String,
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port: usize,
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}
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fn main() {
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let code = r#"
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let
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lib = import <nixpkgs/lib>;
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host = lib.strings.concatStringsSep "." ["foo" "example" "com"];
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in {
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inherit host;
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port = 4242;
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}
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"#;
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let result = tvix_serde::from_str_with_config::<Config, _>(code, |eval_builder| {
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eval_builder.enable_impure(None)
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});
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match result {
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Ok(cfg) => println!("Config says: {}:{}", cfg.host, cfg.port),
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Err(e) => eprintln!("{:?} / {}", e, e),
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}
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}
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