Lua a nice start, here is a walk-through that I have saved from somewhere:
- lmathlib.c, lstrlib.c: get familiar with the external C API. Don't bother with the pattern matcher though. Just the easy functions.
- lapi.c: Check how the API is implemented internally. Only skim this to get a feeling for the code. Cross-reference to lua.h and luaconf.h as needed.
- lobject.h: tagged values and object representation. skim through this first. you'll want to keep a window with this file open all the time.
- lstate.h: state objects. ditto.
- lopcodes.h: bytecode instruction format and opcode definitions. easy.
- lvm.c: scroll down to luaV_execute, the main interpreter loop. see how all of the instructions are implemented. skip the details for now. reread later.
- ltm.c: metamethod handling, reread all of lvm.c now.
You may want to reread lapi.c now.
- ldebug.c: surprise waiting for you. abstract interpretation is used to find object names for tracebacks. does bytecode verification, too.
- lparser.c, lcode.c: recursive descent parser, targetting a register-based VM. start from chunk() and work your way through. read the expression parser and the code generator parts last.
- lgc.c: incremental garbage collector. take your time.
I've heard that too, but haven't read any of its source myself. (The OpenBSD userland is particularly good because it has a lot of utilities that are useful but small, and whose code can be read in isolation.)
I would. The approach to testing is fantastic, the style is extremely consistent, the comments and commentary are well thought out, and I find it a good compromise between clarity and efficiency. Why wouldn't you recommend it?
