commit 48d7a0a9070065db6fad2f3351f148173fda1be2
parent bff7aa3bb4fb5134badc417ccec4926016993d5e
Author: Brian Swetland <swetland@frotz.net>
Date: Mon, 9 Mar 2020 04:07:18 -0700
notebook: thougts on the path to self-hosting
Diffstat:
1 file changed, 46 insertions(+), 0 deletions(-)
diff --git a/docs/notebook.md b/docs/notebook.md
@@ -2,4 +2,50 @@
A place to jot down ideas and/or commentary about the work in progress.
+### 2020 Mar 09 - Path to Self-Hosting
+
+As a big goal of the project is for the compiler to be self-hosted, able
+to compile itself, and the bigger and more complex it and the language
+gets the more work converting the source base over is likely to be, I've
+been thinking about the simplest path to a MVP self-hosting compiler.
+
+Expressions and simple flow control (if/else, while, break, return)
+will be nearly identical to C. Basic function and structure declarations
+will be very similar (mostly flipping the name/type order and some slight
+punctuation changes).
+
+My thinking is by writing the compiler in a strict subset of C that is
+very regular it should be pretty simple to mechanically translate the
+compiler with a script. Ideally entirely by script so I could maintain
+the compiler in both languages long enough to do some "co-simulation"
+style testing to ensure I'm getting identical compilation from both.
+
+The remaining pieces needed to hit the MVP target are, I believe:
+
+- [ ] finish if/while flow control
+- [ ] support for enums, or convert enums to consts
+- [ ] support for structs
+- [ ] support for arrays
+- [ ] support for pointers
+- [ ] support for globals, init'ing gp
+- [ ] support for open/close/read/write "syscalls"
+- [ ] mini std library (malloc-analogue, alloc-only heap, string utils)
+- [ ] rewrite lexer to use if/else instead of case
+- [ ] emulator support for commandline args passing
+
+Okay, that's still a decent chunk of work. But most of it is straight
+forward for a base implementation.
+
+We can survive for a while without floating point, structure extension,
+whatever case/match mechanism ends up looking like, etc, etc. Data
+structures are all about dumb, single-linked lists for now. Hashtables
+or Trees can come much later in the process.
+
+I need to make some decisions on pointers vs references.
+
+I should just make ctx global -- passing it like a this pointer clutters
+up the code and doesn't buy much. And it'll be slower for quite a while,
+since for now param -> ldw -> pointer-in-reg -> ldw -> value in struct is
+more work than just loading relative to the global pointer.
+
