pancanin / cpplox

Interpreter for a custom scripting language

cpplox

Interpreter for a custom scripting language, similar to JS

Demo

You can peek into the supported functionality in this short REPL session.

Steps to build and run

This is a CMake based project, so you can install CMake and do the following steps.

1. Create a build folder in the repo root
2. Change directory into this build
3. Open a terminal and type cmake .. -G"Your generator". There are many types of generators. For windows, if you have Visual studio installed, you can use a windows generator which will generate a VS solution.
4. Compile the actual program and run.

• For windows, if you are working under VS, you can use the IDE to run the project.
• For linux, after the cmake command, you have to run make and run the binary executable.

Important classes

• Main
• Scanner
• Parser
• Interpreter

Bugs

• When the process is terminated with Ctrl + C, the program crashes. When adding Windows.h to handle the Ctrl+C, the project goes wild.
• It would be good to warn users if they input a floating point number which overflows the supported precision in our language. For this, we have to introduce a BigDecimal type of object.
• The primary grammar rule is trying and failing to parse a semicolon at the end of expression. It should not try to parse it, it should stop.

Improvements Plan

• LoxValue is copied a lot while storing and retrieving from Environment storage. Let's improve that.

Lessons learned

• Never ignore the warnings from the compiler. Really odd linking errors could happen and some compilers are more strict than others.
• In visual studio compiler, when you have reference to an object fields in classes, you must import the header files of these classes. Forward declarations won't work for fields.