bynk_check/
ast_text.rs

1//! Short source-text renderings of AST fragments, shared by the agent state
2//! model ([`crate::agent_state`]) and `bynk-ide`'s sequence diagram and effect
3//! summary: a branch's outcome, a match arm's pattern, and a parenthesis peel.
4//! #2220 moved them here from `bynk-ide`'s `sequence.rs` with the state model.
5
6use bynk_syntax::ast::*;
7
8/// A branch's rendered outcome — the tail value the handler yields on that
9/// path (`Ok(view)`), which a renderer shows as a note over the entry
10/// lifeline. `None` when the tail carries no distinguishable reply: a unit
11/// `()` (an else-less `if`'s synthesised branch, or an explicit `()` tail), or
12/// control flow (`if`/`match`/block) that is already rendered as its own
13/// nested structure — repeating it as a note would only add noise.
14pub fn branch_outcome(tail: &Expr) -> Option<String> {
15    let inner = peel_paren(tail);
16    match &inner.kind {
17        ExprKind::UnitLit | ExprKind::If { .. } | ExprKind::Match { .. } | ExprKind::Block(_) => {
18            None
19        }
20        _ => Some(bynk_fmt::expr_to_string(inner)),
21    }
22}
23
24pub fn peel_paren(expr: &Expr) -> &Expr {
25    match &expr.kind {
26        ExprKind::Paren(inner) => peel_paren(inner),
27        _ => expr,
28    }
29}
30
31/// A match arm's branch label — a short rendering of its pattern, since
32/// there is no dedicated pattern-to-source printer to reuse.
33pub fn pattern_summary(pattern: &Pattern) -> String {
34    match pattern {
35        Pattern::Wildcard(_) => "_".to_string(),
36        Pattern::Binding(b) => b.name.clone(),
37        Pattern::Literal { value, .. } => value.describe(),
38        Pattern::Variant {
39            type_name, variant, ..
40        } => match type_name {
41            Some(t) => format!("{}.{}", t.name, variant.name),
42            None => variant.name.clone(),
43        },
44        Pattern::Refined { inner, .. } => pattern_summary(inner),
45        Pattern::Or(patterns, _) => patterns
46            .iter()
47            .map(pattern_summary)
48            .collect::<Vec<_>>()
49            .join(" | "),
50    }
51}
bynk_check/ast_text.rs

bynk_check/
ast_text.rs
