module_util/evaluator/
mod.rs

1//! Generic [`Evaluator`] interface.
2//!
3//! Evaluator implementations:
4//!
5//! - [`Dfs`]
6
7pub mod imports;
8pub use self::imports::Imports;
9
10pub mod trace;
11pub use self::trace::Trace;
12
13pub mod dfs;
14pub use self::dfs::Dfs;
15
16#[cfg(feature = "std")]
17pub mod metrics;
18#[cfg(feature = "std")]
19pub use self::metrics::Metrics;
20
21#[cfg(feature = "std")]
22pub mod acyclic;
23#[cfg(feature = "std")]
24pub use self::acyclic::Acyclic;
25
26///////////////////////////////////////////////////////////////////////////////
27
28/// An evaluator.
29///
30/// An evaluator is the main mechanism with which [`Merge`] is utilized. The
31/// goal of the [`Evaluator`] is to [`Merge`] modules which may of may not
32/// import other modules.
33///
34/// [`Merge`]: module::merge::Merge
35pub trait Evaluator {
36    /// Id of a module.
37    ///
38    /// This can be anything that can uniquely identify a module. For example,
39    /// a filesystem path.
40    type Id;
41
42    /// The type of the module.
43    type Module;
44
45    /// Evaluation error.
46    type Error;
47
48    /// Check whether the evaluator has evaluated any modules.
49    fn is_empty(&self) -> bool;
50
51    /// Get the next module in evaluation order.
52    ///
53    /// Evaluation order is implementation-specific. An implementation might
54    /// choose to evaluate modules in DFS, BFS or some other unspecified order.
55    /// Returns [`None`] when there are no modules left to evaluate.
56    fn next(&mut self) -> Option<Self::Id>;
57
58    /// Evaluate `module` identified by `id` that imports the modules specified
59    /// by `imports`.
60    fn eval(
61        &mut self,
62        id: Self::Id,
63        imports: Imports<Self::Id>,
64        module: Self::Module,
65    ) -> Result<(), Self::Error>;
66
67    /// Destruct the evaluator and get the final value.
68    ///
69    /// Returns [`None`] when no modules have been evaluated.
70    fn finish(self) -> Option<Self::Module>;
71}
module_util/evaluator/mod.rs

module_util/evaluator/
mod.rs
