Fixed bug in inspect expression (test convertible, not same)

And fixed a bug with correctly handling escaped `\"` in expanding string literals

Author: hsutter

include/cpp2util.h

@@ -524,6 +524,13 @@ auto as( X const& x ) -> auto&& {
     return x;
 }
 
+template< typename C, typename X >
+auto as( X const& x ) -> auto 
+    requires (!std::is_same_v<C, X> && requires { C{x}; })
+{
+    return C{x};
+}
+
 template< typename C, typename X >
     requires std::is_base_of_v<C, X>
 auto as( X&& x ) -> C&& {

regression-tests/test-results/pure2-inspect-expression-with-as-in-generic-function.cpp

@@ -22,7 +22,7 @@ auto print_an_int(auto const& x) -> void{
         << std::setw(30) << typeid(x).name() 
         << " value is " 
         << [&] () -> std::string { auto&& __expr = x;
-            if (cpp2::is<int>(__expr)) { if constexpr( requires{std::to_string(cpp2::as<int>(x));} ) if constexpr( std::is_same_v<std::string, CPP2_TYPEOF(std::to_string(cpp2::as<int>(x)))> ) return std::to_string(cpp2::as<int>(x)); else return std::string{}; else return std::string{}; }
+            if (cpp2::is<int>(__expr)) { if constexpr( requires{std::to_string(cpp2::as<int>(x));} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(std::to_string(cpp2::as<int>(x))),std::string> ) return std::to_string(cpp2::as<int>(x)); else return std::string{}; else return std::string{}; }
             else return "not an int"; }
         ()
         << "\n";

regression-tests/test-results/pure2-type-safety-2-with-inspect-expression.cpp

@@ -35,7 +35,7 @@ auto test_generic(auto const& x) -> void{
         << std::setw(30) << typeid(x).name() 
         << " value is " 
         << [&] () -> std::string { auto&& __expr = x;
-            if (cpp2::is<int>(__expr)) { if constexpr( requires{std::to_string(cpp2::as<int>(x));} ) if constexpr( std::is_same_v<std::string, CPP2_TYPEOF(std::to_string(cpp2::as<int>(x)))> ) return std::to_string(cpp2::as<int>(x)); else return std::string{}; else return std::string{}; }
+            if (cpp2::is<int>(__expr)) { if constexpr( requires{std::to_string(cpp2::as<int>(x));} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(std::to_string(cpp2::as<int>(x))),std::string> ) return std::to_string(cpp2::as<int>(x)); else return std::string{}; else return std::string{}; }
             else return "not an int"; }
         ()
         << "\n";

source/cppfront.cpp

@@ -895,7 +895,7 @@ class cppfront
         ++pos;
 
         //  Now we're on the first character of the string itself
-        for ( ; pos < length && text[pos] != '"'; ++pos)
+        for ( ; pos < length && (text[pos] != '"' || text[pos-1] == '\\'); ++pos)
         {
             //  Find the next )$
             if (text[pos] == '$' && text[pos-1] == ')')
@@ -907,7 +907,7 @@ class cppfront
                 //  "next" in the string is the "last" one encountered in the backwards scan
                 auto last_nonwhitespace = '\0';
 
-                for( ; text[open] != '"'; --open)
+                for( ; text[open] != '"' || text[open-1] != '\\'; --open)
                 {
                     if (text[open] == ')') {
                         ++paren_depth;
@@ -1222,7 +1222,7 @@ class cppfront
                 auto return_prefix = std::string{};
                 auto return_suffix = std::string{";"};   // use this to tack the ; back on in the alternative body
                 if (is_expression) {
-                    return_prefix = "{ if constexpr( requires{" + statement + ";} ) if constexpr( std::is_same_v<" + result_type + ", CPP2_TYPEOF(" + statement + ")> ) return ";
+                    return_prefix = "{ if constexpr( requires{" + statement + ";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(" + statement + ")," + result_type + "> ) return ";
                     return_suffix += " }";
                 }