Write a Python compiler.

A Python compiler typically translates Python source code into an intermediate bytecode that runs on the CPython virtual machine. The process involves several stages:

1. Lexical Analysis: The source is tokenized into identifiers, keywords, literals, and operators. Tools like PLY or the built‑in tokenize module can be used.
2. Parsing: Tokens are organized into a parse tree using a grammar (often a context‑free grammar). Python’s grammar is available in lib2to3 or ast modules. A recursive‑descent parser or a parser generator (e.g., ANTLR) can produce an Abstract Syntax Tree (AST).
3. Semantic Analysis: The AST is traversed to perform type checking, name resolution, and scope handling. This step may annotate nodes with type information.
4. Bytecode Generation: The annotated AST is converted into Python bytecode instructions (LOAD_CONST, CALL_FUNCTION, etc.). The dis module shows the resulting opcodes.
5. Execution: The CPython interpreter executes the bytecode via a stack‑based virtual machine.

For a minimal compiler, you can use the ast module to parse code, walk the tree, and emit bytecode using the types.CodeType constructor. Complexity is linear in the size of the source for most phases, but bytecode generation can be O(n) with constant factors depending on the number of operations. A full compiler also handles optimizations like constant folding and dead code elimination, which add additional passes over the AST.

This overview captures the core pipeline; implementing each stage requires careful handling of Python’s dynamic features and extensive testing against the standard library.