Merge pull request #209 from rtfeldman/list-int

Code gen List.set for List Int

src/builtins.rs

@@ -358,7 +358,7 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
-    // get : List a, Int -> Result a [ IndexOutOfBounds ]*
+    // get : List elem, Int -> Result elem [ IndexOutOfBounds ]*
     let index_out_of_bounds = SolvedType::TagUnion(
         vec![(TagName::Global("IndexOutOfBounds".into()), vec![])],
         Box::new(SolvedType::Wildcard),
@@ -380,7 +380,7 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
-    // set : List a, Int, a -> List a
+    // set : List elem, Int, elem -> List elem
     add_type(
         Symbol::LIST_SET,
         SolvedType::Func(
@@ -389,7 +389,7 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
-    // map : List a, (a -> b) -> List b
+    // map : List before, (before -> after) -> List after
     add_type(
         Symbol::LIST_MAP,
         SolvedType::Func(

src/crane/build.rs

@@ -604,6 +604,29 @@ fn call_with_args<'a, B: Backend>(
                 Offset32::new(0),
             )
         }
+        Symbol::LIST_SET => {
+            // set : List elem, Int, elem -> List elem
+            debug_assert!(args.len() == 3);
+
+            let list_ptr = args[0];
+            let elem_index = args[1];
+            let elem = args[2];
+
+            let elem_bytes = 8; // TODO Look this up instead of hardcoding it!
+            let elem_size = builder.ins().iconst(types::I64, elem_bytes);
+
+            // Multiply the requested index by the size of each element.
+            let offset = builder.ins().imul(elem_index, elem_size);
+
+            builder.ins().store_complex(
+                MemFlags::new(),
+                elem,
+                &[list_ptr, offset],
+                Offset32::new(0),
+            );
+
+            list_ptr
+        }
         _ => {
             let fn_id = match scope.get(&symbol) {
                     Some(ScopeEntry::Func{ func_id, .. }) => *func_id,

src/llvm/build.rs

@@ -604,6 +604,24 @@ fn call_with_args<'a, 'ctx, 'env>(
 
             builder.build_load(elem_ptr, "List.get")
         }
+        Symbol::LIST_SET => {
+            debug_assert!(args.len() == 3);
+
+            let list_ptr = args[0].into_pointer_value();
+            let elem_index = args[1].into_int_value();
+            let elem = args[2];
+
+            let builder = env.builder;
+            let elem_bytes = 8; // TODO Look this up instead of hardcoding it!
+            let elem_size = env.context.i64_type().const_int(elem_bytes, false);
+            let offset = builder.build_int_mul(elem_index, elem_size, "MUL_OFFSET");
+
+            let elem_ptr = unsafe { builder.build_gep(list_ptr, &[offset], "elem") };
+
+            builder.build_store(elem_ptr, elem);
+
+            list_ptr.into()
+        }
         _ => {
             let fn_val = env
                 .module

tests/test_gen.rs

@@ -351,6 +351,11 @@ mod test_gen {
         assert_evals_to!("List.getUnsafe [ 12, 9, 6, 3 ] 1", 9, i64);
     }
 
+    #[test]
+    fn set_int_list() {
+        assert_evals_to!("List.getUnsafe (List.set [ 12, 9, 7, 3 ] 1 42) 1", 42, i64);
+    }
+
     #[test]
     fn branch_first_float() {
         assert_evals_to!(