Making progress on using interning in gen_uplc

Done interning for uniqueness. Now to fix the static optimization

Remove unused function

Fixing issues. Have a few remaining tests

crates/aiken-lang/src/gen_uplc/interner.rs

@@ -0,0 +1,57 @@
+use std::collections::HashMap;
+
+use vec1::{vec1, Vec1};
+
+#[derive(Clone)]
+pub struct AirInterner {
+    identifiers: HashMap<String, Vec1<usize>>,
+    current: usize,
+}
+
+impl Default for AirInterner {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Interner that uses previous uniques to prevent future unique collisions
+/// when performing optimizations
+impl AirInterner {
+    pub fn new() -> Self {
+        Self {
+            identifiers: HashMap::new(),
+            current: 0,
+        }
+    }
+
+    pub fn intern(&mut self, text: String) {
+        if let Some(u) = self.identifiers.get_mut(&text) {
+            u.push(self.current);
+
+            self.current += 1;
+        } else {
+            self.identifiers.insert(text, vec1!(self.current));
+
+            self.current += 1;
+        }
+    }
+
+    pub fn pop_text(&mut self, text: String) {
+        if let Some(mut u) = self.identifiers.remove(&text) {
+            if u.len() != 1 {
+                u.pop().unwrap();
+                self.identifiers.insert(text, u);
+            }
+        } else {
+            unreachable!("Looking up a missing text: {}", text);
+        }
+    }
+
+    pub fn lookup_interned(&self, text: &String) -> String {
+        if let Some(u) = self.identifiers.get(text) {
+            format!("{}_id_{}", text, *u.last())
+        } else {
+            unreachable!("Looking up a missing text: {}", text);
+        }
+    }
+}