jigs_core/
meta.rs

1//! Compile-time metadata for every `#[jig]` function in the binary.
2//!
3//! The `#[jig]` macro emits one [`JigMeta`] per annotated function and
4//! registers it via the `inventory` crate. Consumers iterate them at runtime
5//! through [`all`].
6
7/// How a chain entry was reached from the surrounding jig.
8#[derive(Debug, Clone, Copy, PartialEq, Eq)]
9pub enum ChainKind {
10    /// Reached via `.then(...)` — sequential composition. Output of the
11    /// previous step flows into this one.
12    Then,
13    /// Reached via `fork!(...)` — alternative arm. Sibling arms do not
14    /// flow into each other; exactly one arm runs per request.
15    Fork,
16}
17
18/// One entry in a jig's chain: the called jig's name plus how it was
19/// composed with the surrounding pipeline.
20#[derive(Debug, Clone, Copy)]
21pub struct ChainStep {
22    /// Name of the jig referenced at this step.
23    pub name: &'static str,
24    /// Compositional relationship to the surrounding jig.
25    pub kind: ChainKind,
26}
27
28/// Static description of one jig.
29#[derive(Debug, Clone, Copy)]
30pub struct JigMeta {
31    /// Function name as written in source.
32    pub name: &'static str,
33    /// Source file path (as seen by the compiler at expansion time).
34    pub file: &'static str,
35    /// 1-based line of the function declaration.
36    pub line: u32,
37    /// Outer return-type identifier: `"Request"`, `"Response"`, `"Branch"`,
38    /// `"Pending"`, or `"Other"`.
39    pub kind: &'static str,
40    /// Outer first-argument type identifier: `"Request"`, `"Response"`, or
41    /// `"Other"`. Combined with [`Self::kind`] this places a jig in one of three
42    /// semantic buckets: request-side (Request → Request), switching
43    /// (Request → Response/Branch) or response-side (Response → Response).
44    pub input: &'static str,
45    /// `true` if the underlying function is `async fn`.
46    pub is_async: bool,
47    /// Jigs this function references, in source order, tagged with how
48    /// they were composed (`.then(...)` vs `fork!(...)` arm).
49    pub chain: &'static [ChainStep],
50}
51
52impl JigMeta {
53    /// Iterator over chain step names, ignoring kind. Convenience for
54    /// callers that only care about the referenced jig names.
55    pub fn chain_names(&self) -> impl Iterator<Item = &'static str> + '_ {
56        self.chain.iter().map(|s| s.name)
57    }
58}
59
60inventory::collect!(JigMeta);
61
62/// Iterator over every jig registered in the current binary.
63pub fn all() -> impl Iterator<Item = &'static JigMeta> {
64    inventory::iter::<JigMeta>()
65}
66
67/// Look up a jig by name. `O(N)` over the registry.
68pub fn find(name: &str) -> Option<&'static JigMeta> {
69    all().find(|m| m.name == name)
70}
jigs_core/meta.rs

jigs_core/
meta.rs
