From 520c07a6740a3eceb842a6586f7798097a7b2820 Mon Sep 17 00:00:00 2001
From: David Ellis <isv.damocles@gmail.com>
Date: Tue, 12 Mar 2024 16:44:41 -0700
Subject: [PATCH] Keep track of mutability in microstatements, afterall (#673)

---
 src/lntors/function.rs |  4 ++--
 src/program.rs         | 15 +++++++--------
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/lntors/function.rs b/src/lntors/function.rs
index 21972f4c..bb593182 100644
--- a/src/lntors/function.rs
+++ b/src/lntors/function.rs
@@ -13,12 +13,12 @@ pub fn from_microstatement(
 ) -> Result<(String, OrderedHashMap<String, String>), Box<dyn std::error::Error>> {
     match microstatement {
         Microstatement::Arg { .. } => Ok(("".to_string(), out)), // Skip arg microstatements that are just used for discovery during generation
-        Microstatement::Assignment { name, value } => {
+        Microstatement::Assignment { name, value, mutable } => {
             let (val, o) = from_microstatement(value, scope, program, out)?;
             // I wish I didn't have to write the following line because you can't re-assign a
             // variable in a let destructuring, afaict
             out = o;
-            Ok((format!("let {} = {}", name, val,).to_string(), out))
+            Ok((format!("let {} {} = {}", if *mutable { "mut" } else { "" }, name, val,).to_string(), out))
         }
         Microstatement::Value {
             typen,
diff --git a/src/program.rs b/src/program.rs
index d948317a..b5901cd2 100644
--- a/src/program.rs
+++ b/src/program.rs
@@ -392,6 +392,7 @@ impl Const {
 #[derive(Debug)]
 pub enum Microstatement {
     Assignment {
+        mutable: bool,
         name: String,
         value: Box<Microstatement>,
     },
@@ -526,6 +527,7 @@ fn baseassignablelist_to_microstatements(
                                     Microstatement::Assignment {
                                         ref name,
                                         ref value,
+                                        ..
                                     } => {
                                         // If the last microstatement is an assignment, we need to
                                         // reference it as a value and push it back onto the array
@@ -572,7 +574,7 @@ fn baseassignablelist_to_microstatements(
                                     let mut first_microstatement = None;
                                     for microstatement in microstatements.iter().rev() {
                                         match &microstatement {
-                                            Microstatement::Assignment { name, value } if name == &first_var.to_string() => {
+                                            Microstatement::Assignment { name, value, .. } if name == &first_var.to_string() => {
                                                 first_microstatement = Some(Microstatement::Value {
                                                     typen: value.get_type(scope, program)?,
                                                     representation: first_var.to_string(),
@@ -969,12 +971,9 @@ fn declarations_to_microstatements(
     program: &Program,
     mut microstatements: Vec<Microstatement>,
 ) -> Result<Vec<Microstatement>, Box<dyn std::error::Error>> {
-    // We don't care about const vs let in the microstatement world, everything is
-    // immutable and we just create a crap-ton of variables. TODO: We might have
-    // user-provided type declaration data we should look into, at least as a sanity check?
-    let (name, assignables) = match &declarations {
-        parse::Declarations::Const(c) => (c.variable.clone(), &c.assignables),
-        parse::Declarations::Let(l) => (l.variable.clone(), &l.assignables),
+    let (name, assignables, mutable) = match &declarations {
+        parse::Declarations::Const(c) => (c.variable.clone(), &c.assignables, false),
+        parse::Declarations::Let(l) => (l.variable.clone(), &l.assignables, true),
     };
     // Get all of the assignable microstatements generated
     microstatements =
@@ -983,7 +982,7 @@ fn declarations_to_microstatements(
         None => Err("An assignment without a value should be impossible."),
         Some(v) => Ok(Box::new(v)),
     }?;
-    microstatements.push(Microstatement::Assignment { name, value });
+    microstatements.push(Microstatement::Assignment { name, value, mutable });
     Ok(microstatements)
 }