record update foundations

compiler/gen/src/llvm/build.rs

@@ -1035,6 +1035,8 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
         Reset(_) => todo!(),
         Reuse { .. } => todo!(),
 
+        Update { .. } => todo!(),
+
         AccessAtIndex {
             index,
             structure,

compiler/mono/src/borrow.rs

@@ -337,6 +337,7 @@ impl<'a> BorrowInfState<'a> {
                     self.own_var(*x);
                 }
             }
+            Update { .. } => todo!(),
             FunctionCall {
                 call_type,
                 args,

compiler/mono/src/inc_dec.rs

@@ -100,6 +100,13 @@ pub fn occuring_variables_expr(expr: &Expr<'_>, result: &mut MutSet<Symbol>) {
             result.insert(*symbol);
         }
 
+        Update {
+            structure, updates, ..
+        } => {
+            result.insert(*structure);
+            result.extend(updates.iter().map(|r| r.1));
+        }
+
         FunctionCall { args, .. } => {
             // NOTE thouth the function name does occur, it is a static constant in the program
             // for liveness, it should not be included here.
@@ -456,6 +463,8 @@ impl<'a> Context<'a> {
                 self.arena.alloc(Stmt::Let(z, v, l, b))
             }
 
+            Update { .. } => todo!(),
+
             RunLowLevel(op, args) => {
                 let ps = crate::borrow::lowlevel_borrow_signature(self.arena, op);
                 let b = self.add_dec_after_lowlevel(args, ps, b, b_live_vars);

compiler/mono/src/ir.rs

@@ -680,12 +680,18 @@ pub enum Expr<'a> {
         arguments: &'a [Symbol],
     },
     Struct(&'a [Symbol]),
+
     AccessAtIndex {
         index: u64,
         field_layouts: &'a [Layout<'a>],
         structure: Symbol,
         wrapped: Wrapped,
     },
+    Update {
+        structure: Symbol,
+        field_layouts: &'a [Layout<'a>],
+        updates: &'a [(u64, Symbol)],
+    },
 
     Array {
         elem_layout: Layout<'a>,
@@ -846,6 +852,23 @@ impl<'a> Expr<'a> {
                 .text(format!("Index {} ", index))
                 .append(symbol_to_doc(alloc, *structure)),
 
+            Update {
+                structure, updates, ..
+            } => {
+                let it = updates.iter().map(|(index, symbol)| {
+                    alloc
+                        .text(format!(".{} => ", index))
+                        .append(symbol_to_doc(alloc, *symbol))
+                });
+
+                alloc
+                    .text("Update ")
+                    .append(symbol_to_doc(alloc, *structure))
+                    .append(alloc.text("{ "))
+                    .append(alloc.intersperse(it, ", "))
+                    .append(alloc.text(" }"))
+            }
+
             RuntimeErrorFunction(s) => alloc.text(format!("ErrorFunction {}", s)),
         }
     }
@@ -2017,7 +2040,12 @@ pub fn with_hole<'a>(
             }
         }
 
-        Update { .. } => todo!("record access/accessor/update"),
+        Update {
+            record_var, // Variable,
+            ext_var,    // Variable,
+            symbol,     // Symbol,
+            updates,    // SendMap<Lowercase, Field>,
+        } => todo!("record access/accessor/update"),
 
         Closure {
             function_type,
@@ -2965,6 +2993,36 @@ fn substitute_in_expr<'a>(
             }),
             None => None,
         },
+
+        Update {
+            structure,
+            field_layouts,
+            updates,
+        } => {
+            let mut did_change = false;
+            let new_updates = Vec::from_iter_in(
+                updates.iter().map(|(index, s)| match substitute(subs, *s) {
+                    None => (*index, *s),
+                    Some(s) => {
+                        did_change = true;
+                        (*index, s)
+                    }
+                }),
+                arena,
+            );
+
+            if did_change {
+                let updates = new_updates.into_bump_slice();
+
+                Some(Update {
+                    structure: *structure,
+                    field_layouts,
+                    updates,
+                })
+            } else {
+                None
+            }
+        }
     }
 }