fix(iterables): make sure ctx changes are not lost during module expr…

…. compilation

src/lang/builtins.fnk

@@ -97,4 +97,5 @@ init_builtins = fn ctx:
     builtins: rec:
       names: []
       used: []
-      provided: []
+      overrides: {}
+      defaults: {}

src/lang/iterable/map.test.fnk

@@ -36,7 +36,8 @@ describe 'gen 2', fn:
   it 'uses multiple custom iterable impl.', fn:
     expect
       fink2js '
-        {_map_, _filter_} = import "@fink/js-interop/iter.js"
+        {_map_} = import "./iter.fnk"
+        {_filter_} = import "./iter-filter.fnk"
         pipe [1, 2, 3]:
           map item: item * 2
           map item: item / 2

src/lang/iterable/map.test.fnk.snap

@@ -64,7 +64,8 @@ exports[`gen 2 uses legacy iterables 1`] = `
 `;
 
 exports[`gen 2 uses multiple custom iterable impl. 1`] = `
-"import { _map_, _filter_ } from \\"@fink/js-interop/iter.js\\";
+"import { _map_ } from \\"./iter.js\\";
+import { _filter_ } from \\"./iter-filter.js\\";
 {
   let ˆpipe_result_1 = [1, 2, 3];
   ˆpipe_result_1 = _map_((item) => item * 2, false, false)(ˆpipe_result_1);

src/lang/module/init.fnk

@@ -37,18 +37,17 @@ ignorable_import = fn [expr, ctx]:
       false
 
 
-# TODO: std-lib
 with_ctx = fn ctx:
   map item: [item, ctx]
 
-# TODO: std-lib
 map_acc = fn map_fn:
   foo = {}
   # TODO: should be map [item, initial_acc], acc=initial_acc:
   map [item, initial_acc], acc=foo:
     ctx = match acc:
       foo: initial_acc
       else: acc
+
     [result, next_ctx] = map_fn item, ctx
     [[result, next_ctx], next_ctx]
 
@@ -67,7 +66,6 @@ add_builtin_overrides = fn expr, ctx:
         filter {right}: is_builtin right.value, ctx
         fold {right: {value: name}}, override_ctx=ctx:
           override_builtin name, uri, override_ctx
-
       [expr, next_ctx]
     else:
       [expr, ctx]
@@ -169,11 +167,19 @@ transform_module = fn node, ctx:
   [interpreter, first] = get_hashbang maybe_shebang_or_pragmas
 
   [body, end_ctx] = pipe [first, ...rest]:
-    with_ctx ctx
-    map_acc add_builtin_overrides
-    drop_if ignorable_import
-    map_acc transform_body_expr
-    collect_with_ctx ctx
+    map expr, expr_ctx=ctx:
+      [body_expr, body_ctx] = add_builtin_overrides expr, expr_ctx
+      [js_expr, next_ctx] = match body_expr:
+        ignorable_import [?, body_ctx]:
+          [false, body_ctx]
+        else:
+          transform_body_expr body_expr, body_ctx
+      [[js_expr, next_ctx], next_ctx]
+
+    drop_if fn [js]: js == false
+
+    fold [js, ctx], [jss]=[[]]:
+      [[...jss, js], ctx]
     insert_imports
 
   js = file