Tracing-based expression tooltips

1 files changed, 38 insertions, 0 deletions

diff --git a/src/ide/analyze.rs b/src/ide/analyze.rs
new file mode 100644
index 00000000..d8925cfc
--- /dev/null
+++ b/src/ide/analyze.rs
@@ -0,0 +1,38 @@
+use comemo::Track;
+
+use crate::model::{eval, Route, Tracer, Value};
+use crate::syntax::{ast, LinkedNode, SyntaxKind};
+use crate::World;
+
+/// Try to determine a set of possible values for an expression.
+pub fn analyze(world: &(dyn World + 'static), node: &LinkedNode) -> Vec<Value> {
+    match node.cast::<ast::Expr>() {
+        Some(ast::Expr::Ident(_) | ast::Expr::MathIdent(_)) => {
+            if let Some(parent) = node.parent() {
+                if parent.kind() == SyntaxKind::FieldAccess && node.index() > 0 {
+                    return analyze(world, parent);
+                }
+            }
+
+            let span = node.span();
+            let source = world.source(span.source());
+            let route = Route::default();
+            let mut tracer = Tracer::new(Some(span));
+            eval(world.track(), route.track(), tracer.track_mut(), source).ok();
+            return tracer.finish();
+        }
+
+        Some(ast::Expr::FieldAccess(access)) => {
+            if let Some(child) = node.children().next() {
+                return analyze(world, &child)
+                    .into_iter()
+                    .filter_map(|target| target.field(&access.field()).ok())
+                    .collect();
+            }
+        }
+
+        _ => {}
+    }
+
+    vec![]
+}