I am currently taking a course on Compilers. I don't like the idea of blindly memorising facts without any sort of place to apply them to. I want to learn by hands-on doing. 
So, I would like to have the complete code of 3-4 compilers, possibly for languages with different syntax rules (python,c, c++, java) while working through the Dragon book.
If complete compilers are too much of an ask, examples of parsers(well-written LL, LR, LALR parsers) and intermediate-code generators for these languages would also do. 
There is a LOT of code out there on the Internet regarding this, but I want something that is considered to be high-quality and standard. I would be grateful for any resources that you can refer me to in this matter. Thanks.
You can grab code for the Lua compiler from lua.org, they distribute full source, and you could also get GCC's source code, which is both C and C++ compiling.
Good source code for compiler components