Move parameter type inference into the replacement field itself

Author: trflynn89

fly/types/string/detail/format_specifier.hpp

@@ -122,6 +122,14 @@ struct BasicFormatSpecifier
 
     BasicFormatSpecifier() = default;
 
+    /**
+     * Constructor. Initializes the replacement field's format parameter position and infers its
+     * presentation type.
+     *
+     * @param context The context holding the format string parsing state.
+     */
+    explicit constexpr BasicFormatSpecifier(FormatParseContext &context);
+
     BasicFormatSpecifier(BasicFormatSpecifier &&) = default;
     BasicFormatSpecifier &operator=(BasicFormatSpecifier &&) = default;
 
@@ -174,17 +182,6 @@ struct BasicFormatSpecifier
      */
     constexpr void parse(FormatParseContext &context);
 
-    /**
-     * Infer a presentation type for a replacement field based on the corresponding format
-     * parameter's type.
-     *
-     * TODO: This should be private. Once the standard fly::Formatters are updated to inherit from
-     * this structure, they may infer their presentation type.
-     *
-     * @param context The context holding the format string parsing state.
-     */
-    constexpr void infer_type(FormatParseContext &context);
-
     /**
      * The width formatting option may either be a number or a nested replacement field. If a
      * numeric value was specified, return that value. If a nested replacement field was specified,
@@ -337,6 +334,14 @@ struct BasicFormatSpecifier
      */
     constexpr void parse_type(FormatParseContext &context);
 
+    /**
+     * Infer a presentation type for a replacement field based on the corresponding format
+     * parameter's type.
+     *
+     * @param context The context holding the format string parsing state.
+     */
+    constexpr void infer_type(FormatParseContext &context);
+
     /**
      * After parsing a single replacement field, validate all options that were parsed. Raise an
      * error if the field is invalid.
@@ -416,6 +421,14 @@ struct BasicFormatSpecifier
     static constexpr const auto s_decimal = FLY_CHR(CharType, '.');
 };
 
+//==================================================================================================
+template <typename CharType>
+constexpr BasicFormatSpecifier<CharType>::BasicFormatSpecifier(FormatParseContext &context) :
+    m_position(context.next_position())
+{
+    infer_type(context);
+}
+
 //==================================================================================================
 template <typename CharType>
 constexpr void BasicFormatSpecifier<CharType>::parse(FormatParseContext &context)
@@ -587,11 +600,6 @@ constexpr void BasicFormatSpecifier<CharType>::parse_type(FormatParseContext &co
             }
         }
     }
-
-    if (m_type == Type::None)
-    {
-        infer_type(context);
-    }
 }
 
 //==================================================================================================

fly/types/string/detail/format_string.hpp

@@ -164,8 +164,7 @@ constexpr auto BasicFormatString<CharType, ParameterTypes...>::parse_specifier()
     // The opening { will have already been consumed, so the starting position is one less.
     const auto starting_position = m_context.lexer().position() - 1;
 
-    FormatSpecifier specifier {};
-    specifier.m_position = m_context.next_position();
+    FormatSpecifier specifier(m_context);
 
     if (m_context.parameter_type(specifier.m_position) == ParameterType::UserDefined)
     {
@@ -200,10 +199,6 @@ BasicFormatString<CharType, ParameterTypes...>::parse_standard_specifier(FormatS
     {
         specifier.parse(m_context);
     }
-    else
-    {
-        specifier.infer_type(m_context);
-    }
 
     if (!m_context.has_error() && !m_context.lexer().consume_if(s_right_brace))
     {