All parameters default to in

This is the way it used to be, and IMO it's better to have the same default everywhere

For a time I tried out making `copy` the default for statement/block parameter, because I had been writing several of those in `reflect.h2` (it was really only 7 places though)

But putting back the explicit `copy` in 7 places in `reflect.h2` was not bad, and it actually made the code's value flow clearer -- and clear value flow is super important and a foundational principle throughout Cpp2, from parameter directions to mandatory explicit discard to `const` by default

Author: hsutter

regression-tests/test-results/pure2-interpolation.cpp

@@ -37,7 +37,7 @@ class item {
 #line 9 "pure2-interpolation.cpp2"
 [[nodiscard]] auto main() -> int{
 {
-auto x = 0;
+auto const& x = 0;
 
 #line 11 "pure2-interpolation.cpp2"
     {
@@ -55,13 +55,13 @@ auto x = 0;
     }
 }
 {
-auto x = item();
+auto const& x = item();
 
 #line 25 "pure2-interpolation.cpp2"
     {
         std::cout << std::left << std::setw(20) << CPP2_UFCS_0(name, x) << " color " << std::left << std::setw(10) << CPP2_UFCS_0(color, x) << " price " << std::setw(10) << std::setprecision(3) << CPP2_UFCS_0(price, x) << " in stock = " << std::boolalpha << (cpp2::cmp_greater(CPP2_UFCS_0(count, x),0)) << "\n";
 
-        std::cout << cpp2::to_string(CPP2_UFCS_0(name, x), "{:20}") + " color " + cpp2::to_string(CPP2_UFCS_0(color, x), "{:10}") + " price " + cpp2::to_string(CPP2_UFCS_0(price, x), "{: <10.2f}") + " in stock = " + cpp2::to_string(cpp2::cmp_greater(CPP2_UFCS_0(count, std::move(x)),0)) + "\n";
+        std::cout << cpp2::to_string(CPP2_UFCS_0(name, x), "{:20}") + " color " + cpp2::to_string(CPP2_UFCS_0(color, x), "{:10}") + " price " + cpp2::to_string(CPP2_UFCS_0(price, x), "{: <10.2f}") + " in stock = " + cpp2::to_string(cpp2::cmp_greater(CPP2_UFCS_0(count, x),0)) + "\n";
     }
 }
 

regression-tests/test-results/pure2-statement-scope-parameters.cpp

@@ -24,7 +24,7 @@ auto main(int const argc_, char** argv_) -> int{
 #line 3 "pure2-statement-scope-parameters.cpp2"
     auto local_int {42}; 
 {
-auto i = local_int;
+auto const& i = local_int;
 
     //  'in' (read-only) statement scope variable
 #line 6 "pure2-statement-scope-parameters.cpp2"

regression-tests/test-results/version

@@ -1,5 +1,5 @@
 
-cppfront compiler v0.2.1   Build 8A01:0916
+cppfront compiler v0.2.1   Build 8A01:1011
 Copyright(c) Herb Sutter   All rights reserved
 
 SPDX-License-Identifier: CC-BY-NC-ND-4.0

source/build.info

@@ -1 +1 @@
-"8A01:0916"
+"8A01:1011"

source/parse.h

@@ -7112,8 +7112,7 @@ class parser
 
         auto n = std::make_unique<parameter_declaration_node>();
         n->pass =
-            is_returns   ? passing_style::out  :
-            is_statement ? passing_style::copy :
+            is_returns ? passing_style::out  :
             passing_style::in;
         n->pos  = curr().position();
 

source/reflect.h

@@ -38,7 +38,7 @@ class alias_declaration;
 #line 827 "reflect.h2"
 class value_member_info;
 
-#line 1281 "reflect.h2"
+#line 1280 "reflect.h2"
 }
 
 }
@@ -693,14 +693,14 @@ auto flag_enum(meta::type_declaration& t) -> void;
 
 auto cpp2_union(meta::type_declaration& t) -> void;
 
-#line 1175 "reflect.h2"
+#line 1174 "reflect.h2"
 //-----------------------------------------------------------------------
 //
 //  print - output a pretty-printed visualization of t
 //
 auto print(cpp2::in<meta::type_declaration> t) -> void;
 
-#line 1185 "reflect.h2"
+#line 1184 "reflect.h2"
 //-----------------------------------------------------------------------
 //
 //  apply_metafunctions
@@ -711,7 +711,7 @@ auto print(cpp2::in<meta::type_declaration> t) -> void;
     auto const& error
     ) -> bool;
 
-#line 1281 "reflect.h2"
+#line 1280 "reflect.h2"
 }
 
 }
@@ -1552,8 +1552,8 @@ auto value = 0;
 #line 1086 "reflect.h2"
     for ( 
 
-          auto const& m : CPP2_UFCS_0(get_members, t) )  { do 
-    if (  CPP2_UFCS_0(is_member_object, m)) 
+           auto const& m : CPP2_UFCS_0(get_members, t) )  { do 
+    if (   CPP2_UFCS_0(is_member_object, m)) 
     {
         CPP2_UFCS(require, m, CPP2_UFCS_0(is_public, m) || CPP2_UFCS_0(is_default_access, m), 
                    "a union alternative cannot be protected or private");
@@ -1599,22 +1599,22 @@ std::string storage = "    _storage: std::aligned_storage_t<cpp2::max( ";
 {
 std::string comma = "";
 
-#line 1129 "reflect.h2"
+#line 1128 "reflect.h2"
         for ( 
 
               auto const& e : alternatives )  { do {
             storage += comma + "sizeof(" + cpp2::to_string(e.type) + ")";
         } while (false); comma = ", "; }
 }
 
-#line 1135 "reflect.h2"
+#line 1134 "reflect.h2"
         storage += " )> = ();\n";
         CPP2_UFCS(add_member, t, std::move(storage));
     }
 }
 
     //  Provide discriminator
-#line 1140 "reflect.h2"
+#line 1139 "reflect.h2"
     CPP2_UFCS(add_member, t, "    _discriminator: " + cpp2::to_string(std::move(discriminator_type)) + " = -1;\n");
 
     //  Add the alternatives: is_alternative, get_alternative, and set_alternative
@@ -1636,7 +1636,7 @@ std::string destroy = "    private destroy: (inout this) = {\n";
 
     //  Add destroy
 
-#line 1159 "reflect.h2"
+#line 1158 "reflect.h2"
     {
         for ( 
               auto const& a : alternatives ) {
@@ -1650,17 +1650,17 @@ std::string destroy = "    private destroy: (inout this) = {\n";
 }
 
     //  Add the destructor
-#line 1171 "reflect.h2"
+#line 1170 "reflect.h2"
     CPP2_UFCS(add_member, t, "    operator=: (move this) = { destroy(); } ");
 }
 
-#line 1179 "reflect.h2"
+#line 1178 "reflect.h2"
 auto print(cpp2::in<meta::type_declaration> t) -> void
 {
     std::cout << CPP2_UFCS_0(print, t) << "\n";
 }
 
-#line 1189 "reflect.h2"
+#line 1188 "reflect.h2"
 [[nodiscard]] auto apply_metafunctions(
     declaration_node& n, 
     type_declaration& rtype, 
@@ -1752,7 +1752,7 @@ auto print(cpp2::in<meta::type_declaration> t) -> void
     return true; 
 }
 
-#line 1281 "reflect.h2"
+#line 1280 "reflect.h2"
 }
 
 }

source/reflect.h2

@@ -82,7 +82,7 @@ compiler_services: @polymorphic_base @copyable type =
 
         //  First split this string into source_lines
         //
-        (newline_pos := source.find('\n')) 
+        (copy newline_pos := source.find('\n')) 
         if  source.ssize() > 1
             && newline_pos != source.npos
         {
@@ -847,7 +847,7 @@ basic_enum: (
 
     found_non_numeric := false;
 
-    (value: std::string = "-1")
+    (copy value: std::string = "-1")
     for  t.get_members()
     do   (m)
     if   m.is_member_object()
@@ -960,7 +960,7 @@ basic_enum: (
     }
 
     //  Provide a 'to_string' function to print enumerator name(s)
-    (to_string: std::string = "    to_string: (this) -> std::string = { \n")
+    (copy to_string: std::string = "    to_string: (this) -> std::string = { \n")
     {
         if bitwise {
             to_string += "    ret   : std::string = \"(\";\n";
@@ -1082,11 +1082,11 @@ union: (inout t : meta::type_declaration)
 
     //  1. Gather: All the user-written members, and find/compute the max size
 
-    (value := 0)
-    for  t.get_members()
-    next value++
-    do   (m)
-    if   m.is_member_object()
+    (copy value := 0)
+    for   t.get_members()
+    next  value++
+    do    (m)
+    if    m.is_member_object()
     {
         m.require( m.is_public() || m.is_default_access(),
                    "a union alternative cannot be protected or private");
@@ -1122,10 +1122,9 @@ union: (inout t : meta::type_declaration)
     t.remove_marked_members();
 
     //  Provide storage
-    (storage: std::string = "    _storage: std::aligned_storage_t<cpp2::max( ")
+    (copy storage: std::string = "    _storage: std::aligned_storage_t<cpp2::max( ")
     {
-
-        (comma: std::string = "")
+        (copy comma: std::string = "")
         for  alternatives  
         next comma = ", "  
         do   (e) {
@@ -1155,7 +1154,7 @@ union: (inout t : meta::type_declaration)
     }
 
     //  Add destroy
-    (destroy: std::string = "    private destroy: (inout this) = {\n")
+    (copy destroy: std::string = "    private destroy: (inout this) = {\n")
     {
         for  alternatives
         do   (a) {