Parser – Function Operator

The Parser class has a single purpose, to take an input string and return tokens of this string.  This is basically like how the special function operator class works.  So the first improvement made to the Parser class was to change it to a function operator class.

The set input function with a single string argument used to set the input string, plus initialize the position and operator state members, was removed.  A input string argument was added to the constructor and initialization of these other members were added.  The token function used to return pointers to tokens from the input string was changed to the operator function:

TokenPtr token(bool operandState)   →    TokenPtr operator()(bool operandState)

Callers now set the input through the constructor and retrieve tokens like this:

QString input = {...};
...
Parser parse {input};
...
TokenPtr token = parse();

Note that the instance was renamed from "parser" to "parse" as this makes the code a read a little better.  No argument is shown because operand state argument has a default value (which is not shown in the function definition above).

The Tester class for the most part looks like above except that the input string is a standard string and is converted to a C-style string with the c_str() string member function (which is then implicitly converted to a QString).  This won't be needed once the parser uses standard strings.

The Translator class changes are a slightly different form because it contains a parser pointer member defined as a std::unique_ptr.  Previously, a single instance was created for the life of the translator instance.  There is no reason to do this since there is nothing in the parser instance that needs to be retained between translations.  A new parser instance is created for each translation and must be deferenced to obtain tokens:

m_parse.reset(new Parser {input});
...
token = (*m_parse)(operand);

And finally before returning, the translate function resets the parser member pointer to the default pointer (calls the reset function with no argument), which deletes the parser instance.  The Translator class will also be changed to a function operator class so this final reset won't be necessary.

[branch parser commit 9e782539f3]

Utility – Base File Name

Most of the simpler transition to using the STL classes has been completed, though there is still quite a few Qt classes in the non-GUI classes.  For example, the string member of Token class is still a QString, but the Parser class, needs significant changes to use this member as a standard string.  Since these non-GUI classes need major changes, each will be handled in separate topic branches.  Before concluding , the stl branch, some minor refactoring was done.

The base file name function was created in the Command Line class when Qt dependency was removed from the Tester class.  This function takes a standard string file path argument and returns a standard string base file name, but uses a QFileInfo function to do its work (which is the easiest platform independent way to handle file name paths, because for instance, Windows and Linux use different directory separator characters - back slash vs. forward slash).

All Qt dependency has been removed from the Command Line class except for this static function.  There was no other logical class to put this function so that it could be used by both the Command Line and Tester classes.  A new Utility class was created to hold this function.  Its header file includes the standard string header file and its source file contains the QFileInfo header, which shields the users from having to know about Qt.  This class, like the Status Message class (see post), was made so that it can't be instanced or used as a base class.  (Other similar functions can be added in the future.)

The Tester class had one remaining dependency on the Command Line class.  The instance pointer of the Command Line is passed to run function as an argument.  This instance was only used to call the copyright statement function.  This argument was changed to a standard string for the copyright statement, which is now generated in the Command Line constructor and passed to the run function.

[branch stl commit 3020cd6827]

This concludes the initial (simpler) changes transitioning non-GUI classes to STL use.  The stl branch was merged into the develop branch and deleted.  A new branch will be created for the next set of C++11/STL related changes, which will be the replacement of Qt with the STL in the Parser class.

[branch develop merge commit a8bd956bb0]