Adjust type output.

code/compiler/12/type.cpp

@@ -5,6 +5,8 @@
 #include <vector>
 #include "error.hpp"
 
+bool type::is_arrow(const type_mgr& mgr) const { return false; }
+
 void type_scheme::print(const type_mgr& mgr, std::ostream& to) const {
     if(forall.size() != 0) {
         to << "forall ";
@@ -34,20 +36,35 @@ void type_var::print(const type_mgr& mgr, std::ostream& to) const {
     }
 }
 
+bool type_var::is_arrow(const type_mgr& mgr) const {
+    auto it = mgr.types.find(name);
+    if(it != mgr.types.end()) {
+        return it->second->is_arrow(mgr);
+    } else {
+        return false;
+    }
+}
+
 void type_base::print(const type_mgr& mgr, std::ostream& to) const {
     to << name;
 }
 
 void type_arr::print(const type_mgr& mgr, std::ostream& to) const {
+    bool print_parenths = left->is_arrow(mgr);
+    if(print_parenths) to << "(";
     left->print(mgr, to);
-    to << " -> (";
+    if(print_parenths) to << ")";
+    to << " -> ";
     right->print(mgr, to);
-    to << ")";
+}
+
+bool type_arr::is_arrow(const type_mgr& mgr) const {
+    return true;
 }
 
 void type_app::print(const type_mgr& mgr, std::ostream& to) const {
     constructor->print(mgr, to);
-    to << "* ";
+    to << "*";
     for(auto& arg : arguments) {
         to << " ";
         arg->print(mgr, to);

code/compiler/12/type.hpp

@@ -11,6 +11,7 @@ struct type {
     virtual ~type() = default;
 
     virtual void print(const type_mgr& mgr, std::ostream& to) const = 0;
+    virtual bool is_arrow(const type_mgr& mgr) const;
 };
 
 using type_ptr = std::shared_ptr<type>;
@@ -34,6 +35,7 @@ struct type_var : public type {
         : name(std::move(n)) {}
 
     void print(const type_mgr& mgr, std::ostream& to) const;
+    bool is_arrow(const type_mgr& mgr) const;
 };
 
 struct type_base : public type {
@@ -65,6 +67,7 @@ struct type_arr : public type {
         : left(std::move(l)), right(std::move(r)) {}
 
     void print(const type_mgr& mgr, std::ostream& to) const;
+    bool is_arrow(const type_mgr& mgr) const;
 };
 
 struct type_app : public type {