diff --git a/include/gwfmt.h b/include/gwfmt.h
index 98f1189..2901690 100644
--- a/include/gwfmt.h
+++ b/include/gwfmt.h
@@ -45,7 +45,7 @@ ANN void gwfmt_lparen(Gwfmt *a);
 ANN void gwfmt_rparen(Gwfmt *a);
 ANN void gwfmt_lbrace(Gwfmt *a);
 ANN void gwfmt_rbrace(Gwfmt *a);
-ANN void gwfmt_exp(Gwfmt *a, Exp b);
+ANN void gwfmt_exp(Gwfmt *a, Exp* b);
 ANN void gwfmt_func_def(Gwfmt *a, Func_Def b);
 ANN void gwfmt_class_def(Gwfmt *a, Class_Def b);
 ANN void gwfmt_enum_def(Gwfmt *a, Enum_Def b);
diff --git a/include/gwfmt_internal.h b/include/gwfmt_internal.h
index 72e704a..d59fc1b 100644
--- a/include/gwfmt_internal.h
+++ b/include/gwfmt_internal.h
@@ -11,8 +11,8 @@ ANN static void gwfmt_prim_float(Gwfmt *a, m_float *b);
 ANN static void gwfmt_prim_str(Gwfmt *a, struct AstString *b);
 ANN static void gwfmt_prim_array(Gwfmt *a, Array_Sub *b);
 ANN static void gwfmt_prim_range(Gwfmt *a, Range **b);
-ANN static void gwfmt_prim_hack(Gwfmt *a, Exp *b);
-ANN static void gwfmt_prim_interp(Gwfmt *a, Exp *b);
+ANN static void gwfmt_prim_hack(Gwfmt *a, Exp* *b);
+ANN static void gwfmt_prim_interp(Gwfmt *a, Exp* *b);
 ANN static void gwfmt_prim_char(Gwfmt *a, m_str *b);
 ANN static void gwfmt_prim_nil(Gwfmt *a, void *b);
 ANN static void gwfmt_prim(Gwfmt *a, Exp_Primary *b);
diff --git a/src/gwfmt.c b/src/gwfmt.c
index e3369a6..410d799 100644
--- a/src/gwfmt.c
+++ b/src/gwfmt.c
@@ -206,7 +206,7 @@ ANN static bool arg_parse(GwArg *a, int argc, char **argv) {
 }
 
 int main(int argc, char **argv) {
-  MemPool       mp  = mempool_ini(sizeof(struct Exp_));
+  MemPool       mp  = mempool_ini(sizeof(Exp));
   SymTable *    st  = new_symbol_table(mp, 65347); // could be smaller
   struct PPArg_ ppa = {.fmt = 1};
   pparg_ini(mp, &ppa);
diff --git a/src/lint.c b/src/lint.c
index 527118f..4b98e34 100644
--- a/src/lint.c
+++ b/src/lint.c
@@ -167,10 +167,10 @@ ANN void gwfmt_indent(Gwfmt *a) {
   }
 }
 
-ANN static void paren_exp(Gwfmt *a, Exp b);
-ANN static void maybe_paren_exp(Gwfmt *a, Exp b);
+ANN static void paren_exp(Gwfmt *a, Exp* b);
+ANN static void maybe_paren_exp(Gwfmt *a, Exp* b);
 ANN static void gwfmt_array_sub2(Gwfmt *a, Array_Sub b);
-ANN static void gwfmt_prim_interp(Gwfmt *a, Exp *b);
+ANN static void gwfmt_prim_interp(Gwfmt *a, Exp* *b);
 
 #define _FLAG(a, b) (((a)&ae_flag_##b) == (ae_flag_##b))
 ANN static void gwfmt_flag(Gwfmt *a, ae_flag b) {
@@ -306,13 +306,13 @@ ANN static void gwfmt_range(Gwfmt *a, Range *b) {
   gwfmt_rbrack(a);
 }
 
-ANN static void gwfmt_prim_dict(Gwfmt *a, Exp *b) {
-  Exp e = *b;
+ANN static void gwfmt_prim_dict(Gwfmt *a, Exp* *b) {
+  Exp* e = *b;
   gwfmt_lbrace(a);
   gwfmt_space(a);
   do {
-    const Exp next  = e->next;
-    const Exp nnext = next->next;
+    Exp* next  = e->next;
+    Exp* nnext = next->next;
     e->next = NULL;
     next->next = NULL;
     gwfmt_exp(a, e);
@@ -563,7 +563,7 @@ ANN static void gwfmt_prim_array(Gwfmt *a, Array_Sub *b) {
 
 ANN static void gwfmt_prim_range(Gwfmt *a, Range **b) { gwfmt_range(a, *b); }
 
-ANN static void gwfmt_prim_hack(Gwfmt *a, Exp *b) {
+ANN static void gwfmt_prim_hack(Gwfmt *a, Exp* *b) {
   COLOR(a, "{-R}", "<<<");
   gwfmt_space(a);
   gwfmt_exp(a, *b);
@@ -772,15 +772,15 @@ ANN static void gwfmt_exp_lambda(Gwfmt *a, Exp_Lambda *b) {
 }
 
 DECL_EXP_FUNC(gwfmt, void, Gwfmt *)
-ANN void gwfmt_exp(Gwfmt *a, Exp b) {
+ANN void gwfmt_exp(Gwfmt *a, Exp* b) {
   if(b->paren) gwfmt_lparen(a);
   gwfmt_exp_func[b->exp_type](a, &b->d);
   if(b->paren) gwfmt_rparen(a);
   NEXT(a, b, gwfmt_exp)
 }
 
-ANN static void gwfmt_prim_interp(Gwfmt *a, Exp *b) {
-  Exp e = *b;
+ANN static void gwfmt_prim_interp(Gwfmt *a, Exp* *b) {
+  Exp* e = *b;
   const uint16_t delim = e->d.prim.d.string.delim;
   gwfmt_delim(a, delim);
   color(a, "{/Y}");
@@ -802,7 +802,7 @@ ANN static void gwfmt_prim_interp(Gwfmt *a, Exp *b) {
 }
 
 ANN static void gwfmt_array_sub2(Gwfmt *a, Array_Sub b) {
-  Exp e = b->exp;
+  Exp* e = b->exp;
   for (m_uint i = 0; i < b->depth; ++i) {
     gwfmt_lbrack(a);
     if (e) {
@@ -813,7 +813,7 @@ ANN static void gwfmt_array_sub2(Gwfmt *a, Array_Sub b) {
   }
 }
 
-ANN static void paren_exp(Gwfmt *a, Exp b) {
+ANN static void paren_exp(Gwfmt *a, Exp* b) {
   gwfmt_lparen(a);
   //if(b->exp_type != ae_exp_primary &&
   //   b->d.prim.prim_type != ae_prim_nil)
@@ -821,7 +821,7 @@ ANN static void paren_exp(Gwfmt *a, Exp b) {
   gwfmt_rparen(a);
 }
 
-ANN static void maybe_paren_exp(Gwfmt *a, Exp b) {
+ANN static void maybe_paren_exp(Gwfmt *a, Exp* b) {
   if (b->next)
     paren_exp(a, b);
   else