Add initial draft of symtable module.

src/lib.rs

@@ -8,4 +8,4 @@ extern crate log;
 
 pub mod compile;
 pub mod error;
-mod symboltable;
+pub mod symboltable;

src/symboltable.rs

@@ -36,7 +36,7 @@ pub fn statements_to_symbol_table(
     Ok(symbol_table)
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub enum SymbolRole {
     Global,
     Nonlocal,
@@ -45,6 +45,7 @@ pub enum SymbolRole {
 }
 
 /// Captures all symbols in the current scope, and has a list of subscopes in this scope.
+#[derive(Clone)]
 pub struct SymbolScope {
     /// A set of symbols present on this scope level.
     pub symbols: HashMap<String, SymbolRole>,