Start work on scope resolver

TODO.md

@@ -1,5 +1,8 @@
 # TODO items
 
+## General code cleanup
+- standardize on an error type that isn't String
+
 ## Reduction
  - make a good type for actual language builtins to avoid string comparisons
 

schala-lang/language/src/ast.rs

@@ -27,6 +27,10 @@ impl<T> Meta<T> {
   pub fn node(&self) -> &T {
     &self.n
   }
+
+  pub fn mut_node(&mut self) -> &mut T {
+    &mut self.n
+  }
 }
 
 //TODO this PartialEq is here to make tests work - find a way to make it not necessary
@@ -46,7 +50,7 @@ pub struct AST(pub Vec<Meta<Statement>>);
 #[derive(Debug, PartialEq, Clone)]
 pub enum Statement {
   ExpressionStatement(Meta<Expression>),
-  Declaration(Declaration),
+  Declaration(Declaration), //TODO Declaration should also be Meta-wrapped; only Expression and Declaration are Meta-wrapped maybe?
 }
 
 pub type Block = Vec<Meta<Statement>>;

schala-lang/language/src/scope_resolution.rs

@@ -2,5 +2,19 @@ use crate::ast::*;
 
 pub fn resolve_scopes(ast: &mut AST) -> Result<(), String> {
   println!("Resolving scopes - nothing so far!");
+  for statement in ast.0.iter_mut() {
+    match statement.mut_node() {
+      Statement::Declaration(ref mut decl) => resolve_decl(decl),
+      Statement::ExpressionStatement(ref mut expr) => resolve_expr(expr),
+    }?;
+  }
+  Ok(())
+}
+
+fn resolve_decl(decl: &mut Declaration) -> Result<(), String> {
+  Ok(())
+}
+
+fn resolve_expr(expr: &mut Meta<Expression>) -> Result<(), String> {
   Ok(())
 }