Add first draft public API to navigate the design

Author: kraigher

vhdl_lang/src/analysis.rs

@@ -26,6 +26,9 @@ mod standard;
 mod static_expression;
 mod target;
 
+// @TODO consider moving facade into analysis
+pub(crate) use {lock::ReadGuard, root::AnalysisData};
+
 #[cfg(test)]
 pub(crate) mod tests;
 pub(crate) use root::{Library, LockedUnit};

vhdl_lang/src/analysis/root.rs

@@ -261,10 +261,11 @@ impl Library {
         })
     }
 
+    // @TODO optimize O() complexity
     pub(crate) fn secondary_units<'a>(
         &'a self,
         primary: &'a Symbol,
-    ) -> impl Iterator<Item = &'a LockedUnit> {
+    ) -> impl Iterator<Item = &'a LockedUnit> + 'a {
         self.units.iter().filter_map(move |(key, value)| match key {
             UnitKey::Secondary(sym, _) if primary == sym => Some(value),
             _ => None,