Options: Add support for parsing double dot in ratio

doc/user/PARSING.md

@@ -41,6 +41,7 @@ with removing the point and precision when the value is exactly an integer.
 
 The following formats are supported when parsing a string into a ratio:
  - percent% where percent is a double
+ - dividend:divisor where both are doubles
  - dividend/divisor where both are doubles
  - double
 

library/private/options_tools.h.in

@@ -162,10 +162,10 @@ ratio_t parse(const std::string& str)
       return stodStrict(str.substr(0, str.size() - 1)) / 100;
     }
 
-    const std::size_t i = str.find('/');
-    if (i != std::string::npos)
+    const std::size_t sep = str.find_first_of(":/");
+    if (sep != std::string::npos)
     {
-      return stodStrict(str.substr(0, i)) / stodStrict(str.substr(i + 1, str.size() - i - 1));
+      return stodStrict(str.substr(0, sep)) / stodStrict(str.substr(sep + 1));
     }
 
     return stodStrict(str);

library/testing/TestSDKOptionsIO.cxx

@@ -61,6 +61,8 @@ int TestSDKOptionsIO(int argc, char* argv[])
 
   test.parse<f3d::ratio_t>("ratio_t", "0.1234", 0.1234);
   test.parse<f3d::ratio_t>("ratio_t", "12.34%", 0.1234);
+  test.parse<f3d::ratio_t>("ratio_t", "1/2", 0.5);
+  test.parse<f3d::ratio_t>("ratio_t", "1:2", 0.5);
   test.parse_expect<f3d::ratio_t, parsing_exception>("invalid ratio_t", "12.34&");
   test.parse<f3d::ratio_t>("ratio_t", "-2/-3.5", 2.0 / 3.5);
   test.parse_expect<f3d::ratio_t, parsing_exception>("invalid ratio_t", "1/2/3");