lab 6

src/util.rs

@@ -1,11 +1,42 @@
+use std::collections::HashSet;
 use std::io;
 
+use crate::representation::intermediate::IntermediateValue;
+use crate::symbols::Symbol;
 use crate::{
     ast::{typed::TypedExpr, UntypedExpr},
     representation::intermediate::IntermediateExpr,
     symbols::SymbolsTable,
 };
 
+pub fn collect_used_symbols(expr: &[IntermediateExpr]) -> Vec<Symbol> {
+    let mut used_symbols = HashSet::new();
+
+    for expr in expr {
+        match expr {
+            IntermediateExpr::IntToFloat { result, value } => {
+                used_symbols.insert(*result);
+                if let IntermediateValue::Var { name } = value {
+                    used_symbols.insert(*name);
+                }
+            }
+            IntermediateExpr::BinOp {
+                result, lhs, rhs, ..
+            } => {
+                used_symbols.insert(*result);
+                if let IntermediateValue::Var { name } = lhs {
+                    used_symbols.insert(*name);
+                }
+                if let IntermediateValue::Var { name } = rhs {
+                    used_symbols.insert(*name);
+                }
+            }
+        }
+    }
+
+    used_symbols.into_iter().collect()
+}
+
 pub fn print_intermediate_exprs(
     exprs: &[IntermediateExpr],
     writer: &mut impl io::Write,