more

analysis/src/lower.rs

@@ -1,12 +1,50 @@
 use parser::{ast, Span};
 use rustc_hash::FxHashMap;
 
-use crate::hir::{self, Symbol};
+use crate::hir::{self, DefId, Symbol};
 
 pub struct LowerCtx<'hir> {
     hir_symbol_intern: lasso::Rodeo,
     hir_arena: &'hir bumpalo::Bump,
     global_symbols: FxHashMap<Symbol, &'hir hir::ExternalDecl>,
+    scope: Scope,
+}
+
+struct Scope {
+    parent: Option<Box<Scope>>,
+    variables: FxHashMap<Symbol, DefId>,
+}
+
+impl Scope {
+    fn new() -> Self {
+        Self {
+            parent: None,
+            variables: FxHashMap::default(),
+        }
+    }
+
+    fn insert(&mut self, symbol: Symbol, def_id: DefId) {
+        self.variables.insert(symbol, def_id);
+    }
+
+    fn enter_new(&mut self) {
+        let new = Self::new();
+        let this = std::mem::replace(self, new);
+        self.parent = Some(Box::new(this));
+    }
+
+    fn leave(&mut self) {
+        let old = std::mem::replace(self, Self::new());
+        let parent = old.parent.expect("parent not found when leaving scope");
+        *self = *parent;
+    }
+
+    fn lookup(&self, sym: Symbol) -> Option<DefId> {
+        self.variables
+            .get(&sym)
+            .copied()
+            .or_else(|| self.parent.as_ref().and_then(|parent| parent.lookup(sym)))
+    }
 }
 
 impl<'hir> LowerCtx<'hir> {
@@ -16,10 +54,13 @@ impl<'hir> LowerCtx<'hir> {
         todo!()
     }
 
-    fn lower_decl(&mut self, decl: &ast::ExternalDecl, _span: Span) -> hir::ExternalDecl {
+    fn lower_decl(&mut self, decl: &ast::ExternalDecl, span: Span) -> hir::ExternalDecl {
         match decl {
             ast::ExternalDecl::Decl(_) => todo!(),
-            ast::ExternalDecl::FunctionDef(_func) => todo!(),
+            ast::ExternalDecl::FunctionDef(def) => {
+                let _fn_def = self.lower_function_def(def, span);
+                hir::ExternalDecl
+            }
         }
     }
 
@@ -35,11 +76,9 @@ impl<'hir> LowerCtx<'hir> {
 
         let name_sym = self.hir_symbol_intern.get_or_intern(name_ident);
 
-
         if self.global_symbols.contains_key(&name_sym) {
             panic!("function declarated twice! return this error properly! lol!")
         }
-        
 
         todo!()
     }