Note: mypython uses some C++11 features, so it must be compiled with -std=c++11 flag
IF USING G++ WITH WILDCARD: g++ -std=c++11 *.cpp -o mypython
EASIER WITH INCLUDED MAKEFILE: make
Breaks down the file into tokens, which are grouped together in an expression vector, then those expressions are grouped into full token vector (i.e. 2D vector where inner vector stores lines and outer vector contains all of the lines of the program). It seeks out for specific keywords/symbols that are apart of Python syntax. User-defined symbols, such as variable and function names, become their own token. For example: "def foo(x):" becomes {"def", "foo", "(", "x", ")", ":"}. Additionally, it makes identation visible by tagging it with a "tab" token, making evaluation easier. Defined in tokenizer.h/tokenizer.cpp.
Creates a parsable AST by evaluating tokens on a line-by-line basis. Based on context from specific symbols/keywords in the line, the code can determine the kind of statement and goes down its corresponding code path. Nodes in the tree contain a map corresponding to the node's specific attributes and a vector of node pointers, which serve as its children (Refactoring the map into string properties in the node is likely much more performant, but less flexible. In this case, a map isn't needed, but functionality is built around it, so it would take a lot of time to remake). Functions are special in that they are their own AST, which is stored in a map that takes the function name as a key. Defined in ast.h/ast.cpp.
A big part of making ASTs is parsing arthitmetic expressions, which is contained in the AST_HELPER_inToTree function in ast.cpp. It can evaluate basic expressions alongside variables and function calls. Lots of the function is based on GeeksforGeeks's implementation but highly modified to take tokens and read variables and functions. Defined in ast.cpp.
After the AST is created, the program runs by parsing the tree. Starting off at the program node (which is the root), the parser iterates through its children, and based off the type of statement (assignment, condtional, function defintion, etc.), it evalutes the subtree, stores any info about the scope's variables in a map, calls the necessary functions, etc. When a function is called, a new AST is created, which effectively serves as a new scope, and the parentScope is stored in the new AST, which is necessary for looking up the scope chain. After evaluation, a function returns its corresponding value, and program evaluation continues until all of the children nodes have been evalutated. Defined in ast.h/ast.cpp.