rudus/src/compiler.rs

use crate::parser::Ast;
use crate::parser::StringPart;
use crate::spans::Spanned;
use crate::value::*;
use chumsky::prelude::SimpleSpan;
use num_derive::{FromPrimitive, ToPrimitive};
use num_traits::FromPrimitive;
use regex::Regex;
use std::cell::RefCell;
use std::collections::HashMap;
use std::rc::Rc;

#[derive(Copy, Clone, Debug, PartialEq, Eq, FromPrimitive, ToPrimitive)]
pub enum Op {
    Noop,
    Nothing,
    Nil,
    True,
    False,
    Constant,
    Jump,
    JumpIfFalse,
    JumpIfTrue,
    Pop,
    PopN,
    PushBinding,
    PushGlobal,
    Store,
    StoreAt,
    Stash,
    Load,
    ResetMatch,
    Match,
    MatchNil,
    MatchTrue,
    MatchFalse,
    PanicIfNoMatch,
    MatchConstant,
    MatchString,
    PushStringMatches,
    MatchType,
    MatchTuple,
    MatchSplattedTuple,
    PushTuple,
    LoadTuple,
    LoadSplattedTuple,
    MatchList,
    MatchSplattedList,
    LoadList,
    LoadSplattedList,
    PushList,
    AppendList,
    ConcatList,
    PushDict,
    AppendDict,
    ConcatDict,
    LoadDictValue,
    MatchDict,
    MatchSplattedDict,
    DropDictEntry,
    PushBox,
    GetKey,
    PanicNoWhen,
    JumpIfNoMatch,
    JumpIfMatch,
    PanicNoMatch,
    TypeOf,
    JumpBack,
    JumpIfZero,
    Duplicate,
    Decrement,
    Truncate,
    MatchDepth,
    Panic,
    EmptyString,
    ConcatStrings,
    Stringify,

    Call,
    TailCall,
    Return,
    Partial,

    Eq,
    Add,
    Sub,
    Mult,
    Div,
    Unbox,
    BoxStore,
    Assert,
    Get,
    At,

    Not,
    Print,
    SetUpvalue,
    GetUpvalue,
    // Inc,
    // Dec,
    // Gt,
    // Gte,
    // Lt,
    // Lte,
    // Mod,
    // Round,
    // Ceil,
    // Floor,
    // Random,
    // Sqrt,

    // Assoc,
    // Concat,
    // Conj,
    // Count,
    // Disj,
    // Dissoc,
    // Range,
    // Rest,
    // Slice,

    // "atan_2" math/atan2
    // "chars" chars
    // "cos" math/cos
    // "doc" doc
    // "downcase" string/ascii-lower
    // "pi" math/pi
    // "show" show
    // "sin" math/sin
    // "split" string/split
    // "str_slice" string/slice
    // "tan" math/tan
    // "trim" string/trim
    // "triml" string/triml
    // "trimr" string/trimr
    // "upcase" string/ascii-upper
}

impl std::fmt::Display for Op {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        use Op::*;
        let rep = match self {
            Noop => "noop",
            Nothing => "nothing",
            Nil => "nil",
            True => "true",
            False => "false",
            Constant => "constant",
            Jump => "jump",
            JumpIfFalse => "jump_if_false",
            JumpIfTrue => "jump_if_true",
            Pop => "pop",
            PopN => "pop_n",
            PushBinding => "push_binding",
            PushGlobal => "push_global",
            Store => "store",
            StoreAt => "store_at",
            Stash => "stash",
            Load => "load",
            Match => "match",
            MatchNil => "match_nil",
            MatchTrue => "match_true",
            MatchFalse => "match_false",
            ResetMatch => "reset_match",
            PanicIfNoMatch => "panic_if_no_match",
            MatchConstant => "match_constant",
            MatchString => "match_string",
            PushStringMatches => "push_string_matches",
            MatchType => "match_type",
            MatchTuple => "match_tuple",
            MatchSplattedTuple => "match_splatted_tuple",
            PushTuple => "push_tuple",
            LoadTuple => "load_tuple",
            LoadSplattedTuple => "load_splatted_tuple",
            MatchList => "match_list",
            MatchSplattedList => "match_splatted_list",
            LoadList => "load_list",
            LoadSplattedList => "load_splatted_list",
            PushList => "push_list",
            AppendList => "append_list",
            ConcatList => "concat_list",
            PushDict => "push_dict",
            AppendDict => "append_dict",
            ConcatDict => "concat_dict",
            LoadDictValue => "load_dict_value",
            MatchDict => "match_dict",
            MatchSplattedDict => "match_splatted_dict",
            DropDictEntry => "drop_dict_entry",
            PushBox => "push_box",
            GetKey => "get_key",
            PanicNoWhen => "panic_no_when",
            JumpIfNoMatch => "jump_if_no_match",
            JumpIfMatch => "jump_if_match",
            PanicNoMatch => "panic_no_match",
            TypeOf => "type_of",
            JumpBack => "jump_back",
            JumpIfZero => "jump_if_zero",
            Decrement => "decrement",
            Truncate => "truncate",
            Duplicate => "duplicate",
            MatchDepth => "match_depth",
            Panic => "panic",
            EmptyString => "empty_string",
            ConcatStrings => "concat_strings",
            Stringify => "stringify",
            Print => "print",

            Eq => "eq",
            Add => "add",
            Sub => "sub",
            Mult => "mult",
            Div => "div",
            Unbox => "unbox",
            BoxStore => "box_store",
            Assert => "assert",
            Get => "get",
            At => "at",

            Not => "not",

            Call => "call",
            Return => "return",
            Partial => "partial",
            TailCall => "tail_call",

            SetUpvalue => "set_upvalue",
            GetUpvalue => "get_upvalue",
        };
        write!(f, "{rep}")
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct Binding {
    name: &'static str,
    depth: isize,
    stack_pos: usize,
}

#[derive(Clone, Debug, PartialEq)]
pub struct Upvalue {
    name: &'static str,
    stack_pos: usize,
}

#[derive(Clone, Debug)]
pub struct StrPattern {
    pub words: Vec<String>,
    pub re: Regex,
}

#[derive(Clone, Debug)]
pub struct Chunk {
    pub constants: Vec<Value>,
    pub bytecode: Vec<u8>,
    pub keywords: Vec<&'static str>,
    pub string_patterns: Vec<StrPattern>,
    pub env: imbl::HashMap<&'static str, Value>,
}

impl Chunk {
    pub fn dissasemble_instr(&self, i: &mut usize) {
        let op = Op::from_u8(self.bytecode[*i]).unwrap();
        use Op::*;
        match op {
            Pop | Store | Stash | Load | Nil | True | False | MatchNil | MatchTrue | MatchFalse
            | PanicIfNoMatch | ResetMatch | GetKey | PanicNoWhen | PanicNoMatch | TypeOf
            | Duplicate | Decrement | Truncate | Noop | LoadTuple | LoadList | Eq | Add | Sub
            | Mult | Div | Unbox | BoxStore | Assert | Get | At | Not | Panic | EmptyString
            | ConcatStrings | Stringify | MatchType | Return | Match | Print | AppendList
            | ConcatList | PushList | PushDict | AppendDict | ConcatDict | Nothing | PushGlobal => {
                println!("{i:04}: {op}")
            }
            Constant | MatchConstant => {
                let next = self.bytecode[*i + 1];
                let value = &self.constants[next as usize].show();
                println!("{i:04}: {:16} {next:03}: {value}", op.to_string());
                *i += 1;
            }
            PushBinding | MatchTuple | MatchSplattedTuple | LoadSplattedTuple | MatchList
            | MatchSplattedList | LoadSplattedList | MatchDict | MatchSplattedDict
            | DropDictEntry | LoadDictValue | PushTuple | PushBox | MatchDepth | PopN | StoreAt
            | Call | SetUpvalue | GetUpvalue | Partial | MatchString | PushStringMatches
            | TailCall => {
                let next = self.bytecode[*i + 1];
                println!("{i:04}: {:16} {next:03}", op.to_string());
                *i += 1;
            }
            Jump | JumpIfFalse | JumpIfTrue | JumpIfNoMatch | JumpIfMatch | JumpBack
            | JumpIfZero => {
                let high = self.bytecode[*i + 1];
                let low = self.bytecode[*i + 2];
                let len = ((high as u16) << 8) + low as u16;
                println!("{i:04}: {:16} {len:05}", op.to_string());
                *i += 2;
            }
        }
    }

    pub fn dissasemble(&self) {
        println!("IDX | CODE           | INFO");
        let mut i = 0;
        while i < self.bytecode.len() {
            self.dissasemble_instr(&mut i);
            i += 1;
        }
    }

    // pub fn kw_from(&self, kw: &str) -> Option<Value> {
    //     self.kw_index_from(kw).map(Value::Keyword)
    // }

    // pub fn kw_index_from(&self, kw: &str) -> Option<usize> {
    //     self.keywords.iter().position(|s| *s == kw)
    // }
}

#[derive(Debug, Clone, PartialEq)]
struct LoopInfo {
    start: usize,
    stack_root: usize,
}

impl LoopInfo {
    fn new(start: usize, stack_root: usize) -> LoopInfo {
        LoopInfo { start, stack_root }
    }
}

fn get_builtin(name: &str, arity: usize) -> Option<Op> {
    match (name, arity) {
        ("type", 1) => Some(Op::TypeOf),
        ("eq?", 2) => Some(Op::Eq),
        ("add", 2) => Some(Op::Add),
        ("sub", 2) => Some(Op::Sub),
        ("mult", 2) => Some(Op::Mult),
        ("div", 2) => Some(Op::Div),
        ("unbox", 1) => Some(Op::Unbox),
        ("store!", 2) => Some(Op::BoxStore),
        ("assert!", 1) => Some(Op::Assert),
        ("get", 2) => Some(Op::Get),
        ("at", 2) => Some(Op::At),
        ("not", 1) => Some(Op::Not),
        ("print!", 1) => Some(Op::Print),

        _ => None,
    }
}

#[derive(Debug, Clone)]
pub struct Compiler<'a> {
    pub chunk: Chunk,
    pub bindings: Vec<Binding>,
    pub scope_depth: isize,
    pub match_depth: usize,
    pub stack_depth: usize,
    pub spans: Vec<SimpleSpan>,
    pub nodes: Vec<&'static Ast>,
    pub ast: &'static Ast,
    pub span: SimpleSpan,
    pub src: &'static str,
    pub name: &'static str,
    pub enclosing: Option<&'a Compiler<'a>>,
    pub upvalues: Vec<Upvalue>,
    loop_info: Vec<LoopInfo>,
    tail_pos: bool,
}

fn is_binding(expr: &Spanned<Ast>) -> bool {
    let (ast, _) = expr;
    use Ast::*;
    match ast {
        Let(..) | LBox(..) | FnDeclaration(..) => true,
        Fn(name, ..) => !name.is_empty(),
        _ => false,
    }
}

fn has_placeholder(args: &[Spanned<Ast>]) -> bool {
    args.iter().any(|arg| matches!(arg, (Ast::Placeholder, _)))
}

impl<'a> Compiler<'a> {
    pub fn new(
        ast: &'static Spanned<Ast>,
        name: &'static str,
        src: &'static str,
        enclosing: Option<&'a Compiler>,
        env: imbl::HashMap<&'static str, Value>,
    ) -> Compiler<'a> {
        let chunk = Chunk {
            constants: vec![],
            bytecode: vec![],
            keywords: vec![],
            string_patterns: vec![],
            env,
        };
        Compiler {
            chunk,
            bindings: vec![],
            scope_depth: -1,
            match_depth: 0,
            stack_depth: 0,
            spans: vec![],
            nodes: vec![],
            ast: &ast.0,
            span: ast.1,
            loop_info: vec![],
            enclosing,
            upvalues: vec![],
            src,
            name,
            tail_pos: false,
        }
    }

    pub fn visit(&mut self, node: &'static Spanned<Ast>) {
        let root_node = self.ast;
        let root_span = self.span;
        let (ast, span) = node;
        self.ast = ast;
        self.span = *span;
        self.compile();
        self.ast = root_node;
        self.span = root_span;
    }

    fn jump(&mut self, op: Op, len: usize) {
        let low = len as u8;
        let high = (len >> 8) as u8;
        self.emit_op(op);
        self.chunk.bytecode.push(high);
        self.chunk.bytecode.push(low);
    }

    fn stub_jump(&mut self, op: Op) -> usize {
        let out = self.chunk.bytecode.len();
        self.emit_op(op);
        self.emit_byte(0xff);
        self.emit_byte(0xff);
        out
    }

    fn patch_jump(&mut self, i: usize, len: usize) {
        let low = len as u8;
        let high = (len >> 8) as u8;
        self.chunk.bytecode[i + 1] = high;
        self.chunk.bytecode[i + 2] = low;
    }

    pub fn emit_constant(&mut self, val: Value) {
        let const_idx = if let Some(idx) = self.chunk.constants.iter().position(|v| *v == val) {
            idx
        } else {
            self.chunk.constants.push(val);
            self.chunk.constants.len() - 1
        };

        if const_idx > u8::MAX as usize {
            panic!(
                "internal Ludus compiler error: too many constants in chunk:{}:: {}",
                self.span, self.ast
            )
        }
        self.emit_op(Op::Constant);
        self.emit_byte(const_idx);
        self.stack_depth += 1;
    }

    fn match_constant(&mut self, val: Value) {
        let constant_index = match self.chunk.constants.iter().position(|v| *v == val) {
            Some(idx) => idx,
            None => {
                self.chunk.constants.push(val);
                self.chunk.constants.len() - 1
            }
        };
        if constant_index > u8::MAX as usize {
            panic!(
                "internal Ludus compiler error: too many constants in chunk:{}:: {}",
                self.span, self.ast
            )
        }
        self.emit_op(Op::MatchConstant);
        self.emit_byte(constant_index);
    }

    fn emit_op(&mut self, op: Op) {
        self.chunk.bytecode.push(op as u8);
        self.spans.push(self.span);
    }

    fn emit_byte(&mut self, byte: usize) {
        self.chunk.bytecode.push(byte as u8);
        self.spans.push(self.span);
    }

    fn len(&self) -> usize {
        self.chunk.bytecode.len()
    }

    pub fn bind(&mut self, name: &'static str) {
        let binding = Binding {
            name,
            depth: self.scope_depth,
            stack_pos: self.stack_depth - self.match_depth - 1,
        };
        println!("{:?}", binding);
        println!("stack: {}; match: {}", self.stack_depth, self.match_depth);
        self.bindings.push(binding);
    }

    fn resolve_local(&self, name: &'static str) -> Option<usize> {
        for binding in self.bindings.iter() {
            if binding.name == name {
                return Some(binding.stack_pos);
            }
        }
        None
    }

    fn resolve_upvalue(&self, name: &'static str) -> Option<usize> {
        self.upvalues.iter().position(|uv| uv.name == name)
    }

    fn get_upvalue(&self, name: &'static str) -> Upvalue {
        let local = self.bindings.iter().find(|b| b.name == name);
        match local {
            Some(binding) => Upvalue {
                name,
                stack_pos: binding.stack_pos,
            },
            None => self.enclosing.unwrap().get_upvalue(name),
        }
    }

    fn resolve_binding(&mut self, name: &'static str) {
        if let Some(pos) = self.resolve_local(name) {
            self.emit_op(Op::PushBinding);
            self.emit_byte(pos);
            self.stack_depth += 1;
            return;
        }
        if let Some(pos) = self.resolve_upvalue(name) {
            self.emit_op(Op::GetUpvalue);
            self.emit_byte(pos);
            self.stack_depth += 1;
            return;
        }
        if self.chunk.env.contains_key(name) {
            self.emit_constant(Value::Keyword(name));
            self.emit_op(Op::PushGlobal);
            return;
        }
        let upvalue = self.get_upvalue(name);
        self.emit_op(Op::GetUpvalue);
        self.emit_byte(self.upvalues.len());
        self.upvalues.push(upvalue);
        self.stack_depth += 1;
    }

    fn resolve_binding_old(&mut self, name: &'static str) {
        match self.resolve_local(name) {
            Some(position) => {
                self.emit_op(Op::PushBinding);
                self.emit_byte(position);
                self.stack_depth += 1;
            }
            None => match self.resolve_upvalue(name) {
                Some(position) => {
                    println!("resolved upvalue: {name} at {position}");
                    self.emit_op(Op::GetUpvalue);
                    self.emit_byte(position);
                    self.stack_depth += 1;
                }
                None => {
                    println!("setting upvalue: {name}");
                    let upvalue = self.get_upvalue(name);
                    self.emit_op(Op::GetUpvalue);
                    self.emit_byte(self.upvalues.len());
                    self.upvalues.push(upvalue);
                    dbg!(&self.upvalues);
                    self.stack_depth += 1;
                }
            },
        }
    }

    fn pop(&mut self) {
        self.emit_op(Op::Pop);
        self.stack_depth -= 1;
    }

    fn pop_n(&mut self, n: usize) {
        match n {
            0 => (),
            1 => self.pop(),
            n => {
                self.emit_op(Op::PopN);
                self.emit_byte(n);
                self.stack_depth -= n;
            }
        }
    }

    fn enter_loop(&mut self) {
        self.loop_info
            .push(LoopInfo::new(self.len(), self.stack_depth));
    }

    fn leave_loop(&mut self) {
        self.loop_info.pop();
    }

    fn loop_info(&self) -> LoopInfo {
        self.loop_info.last().unwrap().clone()
    }

    fn loop_idx(&self) -> usize {
        self.loop_info.last().unwrap().start
    }

    fn loop_root(&self) -> usize {
        self.loop_info.last().unwrap().stack_root
    }

    pub fn compile(&mut self) {
        use Ast::*;
        match self.ast {
            Error => unreachable!(),
            Nil => {
                self.emit_op(Op::Nil);
                self.stack_depth += 1;
            }
            Number(n) => self.emit_constant(Value::Number(*n)),
            Boolean(b) => {
                self.emit_op(if *b { Op::True } else { Op::False });
                self.stack_depth += 1;
            }
            String(s) => {
                self.emit_constant(Value::Interned(s));
            }
            Keyword(s) => self.emit_constant(Value::Keyword(s)),
            Block(lines) => {
                let tail_pos = self.tail_pos;
                self.tail_pos = false;
                // increase the scope
                self.scope_depth += 1;
                // stash the stack depth
                let stack_depth = self.stack_depth;
                // evaluate all the lines but the last
                for expr in lines.iter().take(lines.len() - 1) {
                    // evaluate the expression
                    self.visit(expr);
                    // if it doesn't bind a name, pop the result from the stack
                    if !is_binding(expr) {
                        self.pop();
                    }
                }

                // now, evaluate the last expression in the block
                let last_expr = lines.last().unwrap();
                match last_expr {
                    // if the last expression is a let form,
                    // return the evaluated rhs instead of whatever is last on the stack
                    // we do this by pretending it's a binding
                    (Let(patt, expr), _) => {
                        self.match_depth = 0;
                        self.emit_op(Op::ResetMatch);
                        self.visit(expr);
                        let expr_pos = self.stack_depth - 1;
                        self.visit(patt);
                        self.emit_op(Op::PanicIfNoMatch);
                        self.emit_op(Op::PushBinding);
                        self.emit_byte(expr_pos);
                        self.stack_depth += 1;
                    }
                    // otherwise, just evaluate it and leave the value on the stack
                    _ => {
                        self.tail_pos = tail_pos;
                        self.visit(last_expr);
                    }
                }

                // we've made a new value, so increase the stack level in the compiler
                self.stack_depth += 1;

                // store the value in the return register
                self.emit_op(Op::Store);

                // reset the scope
                self.scope_depth -= 1;
                while let Some(binding) = self.bindings.last() {
                    if binding.depth > self.scope_depth {
                        self.bindings.pop();
                    } else {
                        break;
                    }
                }
                // reset the stack
                self.pop_n(self.stack_depth - stack_depth - 1);
                // load the value from the return register
                self.emit_op(Op::Load);
            }
            If(cond, then, r#else) => {
                let tail_pos = self.tail_pos;
                self.tail_pos = false;
                self.visit(cond);
                let jif_idx = self.stub_jump(Op::JumpIfFalse);
                self.stack_depth -= 1;
                self.tail_pos = tail_pos;
                self.visit(then);
                let jump_idx = self.stub_jump(Op::Jump);
                self.visit(r#else);
                self.stack_depth -= 1;
                let end_idx = self.len();
                let jif_offset = jump_idx - jif_idx;
                let jump_offset = end_idx - jump_idx - 1;
                self.patch_jump(jif_idx, jif_offset);
                self.patch_jump(jump_idx, jump_offset);
            }
            Let(patt, expr) => {
                self.match_depth = 0;
                self.emit_op(Op::ResetMatch);
                self.visit(expr);
                self.visit(patt);
                self.emit_op(Op::PanicIfNoMatch);
            }
            WordPattern(name) => {
                self.emit_op(Op::Match);
                self.bind(name);
            }
            Word(name) | Splat(name) => self.resolve_binding(name),
            PlaceholderPattern => {
                self.emit_op(Op::Match);
            }
            NilPattern => {
                self.emit_op(Op::MatchNil);
            }
            BooleanPattern(b) => {
                if *b {
                    self.emit_op(Op::MatchTrue);
                } else {
                    self.emit_op(Op::MatchFalse);
                }
            }
            NumberPattern(n) => {
                self.match_constant(Value::Number(*n));
            }
            KeywordPattern(s) => {
                let existing_kw = self.chunk.keywords.iter().position(|kw| kw == s);
                let kw_index = match existing_kw {
                    Some(index) => index,
                    None => self.chunk.keywords.len(),
                };
                if kw_index == self.chunk.keywords.len() {
                    self.chunk.keywords.push(s);
                }
                self.match_constant(Value::Keyword(s));
            }
            AsPattern(word, typ) => {
                self.emit_constant(Value::Keyword(typ));
                self.emit_op(Op::MatchType);
                self.stack_depth -= 1;
                self.bind(word);
            }
            StringPattern(s) => {
                self.match_constant(Value::Interned(s));
            }
            TuplePattern(members) => {
                // first, test the tuple against length
                // check if we're splatted
                // different opcodes w/ splats, but same logic
                let mut is_splatted = false;
                if let Some((Splattern(_), _)) = members.last() {
                    is_splatted = true;
                    self.emit_op(Op::MatchSplattedTuple);
                } else {
                    self.emit_op(Op::MatchTuple);
                }

                self.emit_byte(members.len());
                // skip everything if tuple lengths don't match
                let before_load_tup_idx = self.stub_jump(Op::JumpIfNoMatch);

                // set up the per-member conditional logic
                let mut jump_idxes = vec![];
                // stash match_depth, and set it to the tuple len
                let match_depth = self.match_depth;
                self.match_depth = members.len();

                // load the tuple and update the stack len
                if is_splatted {
                    self.emit_op(Op::LoadSplattedTuple);
                    self.emit_byte(members.len());
                } else {
                    self.emit_op(Op::LoadTuple);
                }
                self.stack_depth += members.len();

                // visit each member
                for member in members {
                    // reduce the match depth to start
                    self.match_depth -= 1;
                    self.emit_op(Op::MatchDepth);
                    self.emit_byte(self.match_depth);
                    // visit the pattern member
                    self.visit(member);
                    // and jump if there's no match
                    jump_idxes.push(self.stub_jump(Op::JumpIfNoMatch));
                }

                // if we get here--not having jumped on no match--we're matched; jump the "no match" code
                let jump_idx = self.stub_jump(Op::Jump);

                // patch up the previous no match jumps to jump to clean-up code
                for idx in jump_idxes {
                    self.patch_jump(idx, self.len() - idx - 2)
                }
                // pop everything that was pushed
                // don't change the compiler stack representation, tho
                // we need this as cleanup code with no matches
                // the compiler should still have access to the bindings in this pattern
                self.emit_op(Op::PopN);
                self.emit_byte(members.len());

                // patch up the tuple length match jump
                self.patch_jump(before_load_tup_idx, self.len() - before_load_tup_idx - 3);

                // patch up the yes-matches unconditional jump
                self.patch_jump(jump_idx, self.len() - jump_idx - 3);

                // finally, for any further matches (e.g. nested lists/tuples)
                // add increase the match depth, since we've added a bunch
                // of bindings to the stack
                self.match_depth = match_depth + members.len();
            }
            ListPattern(members) => {
                let mut is_splatted = false;
                if let Some((Splattern(_), _)) = members.last() {
                    is_splatted = true;
                    self.emit_op(Op::MatchSplattedList)
                } else {
                    self.emit_op(Op::MatchList);
                }
                // TODO: lists must be able to be longer than 256 elements; fix this
                self.emit_byte(members.len());
                let before_load_tup_idx = self.stub_jump(Op::JumpIfNoMatch);

                let mut jump_idxes = vec![];
                let match_depth = self.match_depth;
                self.match_depth = members.len();

                if is_splatted {
                    self.emit_op(Op::LoadSplattedList);
                    self.emit_byte(members.len());
                } else {
                    self.emit_op(Op::LoadList);
                }
                self.stack_depth += members.len();

                for member in members {
                    self.match_depth -= 1;
                    self.emit_op(Op::MatchDepth);
                    self.emit_byte(self.match_depth);
                    self.visit(member);
                    jump_idxes.push(self.stub_jump(Op::JumpIfNoMatch));
                }

                let jump_idx = self.stub_jump(Op::Jump);

                for idx in jump_idxes {
                    self.patch_jump(idx, self.len() - idx - 2)
                }

                self.emit_op(Op::PopN);
                self.emit_byte(members.len());

                self.patch_jump(before_load_tup_idx, self.len() - before_load_tup_idx - 3);

                self.patch_jump(jump_idx, self.len() - jump_idx - 3);

                self.match_depth = match_depth + members.len();
            }
            DictPattern(pairs) => {
                // here's an algorithm for dealing with splatted dicts
                // check len to see it's at least as long as the pattern
                // then, match against all the values
                // then push the dict itself as last value
                // and then emit an opcode and constant/keyword to OMIT that key from the dict
                let mut is_splatted = false;
                if let Some((Splattern(_), _)) = pairs.last() {
                    is_splatted = true;
                    self.emit_op(Op::MatchSplattedDict);
                } else {
                    self.emit_op(Op::MatchDict);
                }
                self.emit_byte(pairs.len());
                let before_load_dict_idx = self.stub_jump(Op::JumpIfNoMatch);

                let mut jump_idxes = vec![];
                let dict_stack_pos = self.stack_depth - self.match_depth - 1;
                let mut splattern = None;
                let mut pairs_len = pairs.len();
                if is_splatted {
                    splattern = pairs.last();
                    pairs_len -= 1;
                }

                let match_depth = self.match_depth;
                self.match_depth = 0;
                for pair in pairs.iter().take(pairs_len) {
                    let (PairPattern(key, pattern), _) = pair else {
                        unreachable!()
                    };
                    self.emit_constant(Value::Keyword(key));
                    self.emit_op(Op::LoadDictValue);
                    self.emit_byte(dict_stack_pos);
                    self.visit(pattern);
                    jump_idxes.push(self.stub_jump(Op::JumpIfNoMatch));
                }

                if is_splatted {
                    // pull the dict out of the stack
                    // drop every value in the pattern
                    self.emit_op(Op::PushBinding);
                    self.emit_byte(dict_stack_pos);

                    for pair in pairs.iter().take(pairs_len) {
                        let (PairPattern(key, _), _) = pair else {
                            unreachable!()
                        };
                        self.emit_constant(Value::Keyword(key));
                        self.emit_op(Op::DropDictEntry);
                    }

                    if let Some(splatt) = splattern {
                        self.visit(splatt);
                    }
                }

                self.match_depth = match_depth + pairs.len();

                let jump_idx = self.stub_jump(Op::Jump);

                for idx in jump_idxes {
                    self.patch_jump(idx, self.len() - idx - 2);
                }

                self.emit_op(Op::PopN);
                self.emit_byte(pairs.len());

                self.patch_jump(before_load_dict_idx, self.len() - before_load_dict_idx - 3);
                self.patch_jump(jump_idx, self.len() - jump_idx - 3);
            }
            Splattern(patt) => self.visit(patt),
            InterpolatedPattern(parts, _) => {
                println!("An interpolated pattern of {} parts", parts.len());
                let mut pattern = "".to_string();
                let mut words = vec![];
                for (part, _) in parts {
                    match part {
                        StringPart::Word(word) => {
                            println!("wordpart: {word}");
                            words.push(word.clone());
                            pattern.push_str("(.*)");
                        }
                        StringPart::Data(data) => {
                            println!("datapart: {data}");
                            let data = regex::escape(data);
                            pattern.push_str(data.as_str());
                        }
                        StringPart::Inline(..) => unreachable!(),
                    }
                }
                let re = Regex::new(pattern.as_str()).unwrap();
                let moar_words = words.clone();
                let string_pattern = StrPattern { words, re };

                let pattern_idx = self.chunk.string_patterns.len();
                self.chunk.string_patterns.push(string_pattern);

                self.emit_op(Op::MatchString);
                self.emit_byte(pattern_idx);

                let jnm_idx = self.stub_jump(Op::JumpIfNoMatch);

                self.emit_op(Op::PushStringMatches);
                self.emit_byte(pattern_idx);

                for word in moar_words {
                    let name: &'static str = std::string::String::leak(word);
                    let binding = Binding {
                        name,
                        depth: self.scope_depth,
                        stack_pos: self.stack_depth,
                    };
                    self.bindings.push(binding);
                    self.stack_depth += 1;
                }

                self.patch_jump(jnm_idx, self.len() - jnm_idx - 3);
            }
            PairPattern(_, _) => unreachable!(),
            Tuple(members) => {
                for member in members {
                    self.visit(member);
                }
                self.emit_op(Op::PushTuple);
                self.emit_byte(members.len());
                self.stack_depth = self.stack_depth + 1 - members.len();
            }
            List(members) => {
                self.emit_op(Op::PushList);
                self.stack_depth += 1;
                for member in members {
                    self.visit(member);
                    if matches!(member, (Splat(..), _)) {
                        self.emit_op(Op::ConcatList);
                    } else {
                        self.emit_op(Op::AppendList);
                    }
                    self.stack_depth -= 1;
                }
            }
            LBox(name, expr) => {
                self.visit(expr);
                self.emit_op(Op::PushBox);
                self.bind(name);
            }
            Dict(pairs) => {
                self.emit_op(Op::PushDict);
                self.stack_depth += 1;
                for pair in pairs.iter().rev() {
                    self.visit(pair);
                    if matches!(pair, (Splat(..), _)) {
                        self.emit_op(Op::ConcatDict);
                        self.stack_depth -= 1;
                    } else {
                        self.emit_op(Op::AppendDict);
                        self.stack_depth -= 2;
                    }
                }
            }
            Pair(key, value) => {
                self.emit_constant(Value::Keyword(key));
                self.visit(value);
            }
            // TODO: thread tail position through this
            Synthetic(first, second, rest) => {
                let tail_pos = self.tail_pos;
                self.tail_pos = false;
                match (&first.0, &second.0) {
                    (Word(_), Keyword(_)) => {
                        self.visit(first);
                        self.visit(second);
                        self.emit_op(Op::GetKey);
                        self.stack_depth -= 1;
                    }
                    (Keyword(_), Arguments(args)) => {
                        self.visit(&args[0]);
                        self.visit(first);
                        self.emit_op(Op::GetKey);
                        self.stack_depth -= 1;
                    }
                    (Or, Arguments(args)) => {
                        let stack_depth = self.stack_depth;
                        let mut jump_idxes = vec![];
                        if !args.is_empty() {
                            for arg in args {
                                self.visit(arg);
                                self.emit_op(Op::Stash);
                                jump_idxes.push(self.stub_jump(Op::JumpIfTrue));
                            }
                            for idx in jump_idxes {
                                self.patch_jump(idx, self.len() - idx);
                            }
                            self.emit_op(Op::Load);
                        } else {
                            self.emit_op(Op::False);
                        }
                        self.stack_depth = stack_depth + 1;
                    }
                    (And, Arguments(args)) => {
                        let stack_depth = self.stack_depth;
                        let mut jump_idxes = vec![];
                        if !args.is_empty() {
                            for arg in args {
                                self.visit(arg);
                                self.emit_op(Op::Stash);
                                jump_idxes.push(self.stub_jump(Op::JumpIfFalse));
                            }
                            for idx in jump_idxes {
                                self.patch_jump(idx, self.len() - idx);
                            }
                            self.emit_op(Op::Load);
                        } else {
                            self.emit_op(Op::True);
                        }
                        self.stack_depth = stack_depth + 1;
                    }
                    (Word(fn_name), Arguments(args)) => {
                        if has_placeholder(args) {
                            let arity = args.len();
                            for arg in args {
                                self.visit(arg);
                            }
                            self.resolve_binding(fn_name);
                            self.emit_op(Op::Partial);
                            self.emit_byte(arity);
                            self.stack_depth -= 1;
                        } else {
                            match get_builtin(fn_name, args.len()) {
                                Some(code) => {
                                    for arg in args {
                                        self.visit(arg);
                                    }
                                    self.emit_op(code);
                                    self.stack_depth -= args.len() - 1;
                                }
                                None => {
                                    let arity = args.len();
                                    for arg in args {
                                        self.visit(arg);
                                    }
                                    self.resolve_binding(fn_name);
                                    // if we're in tail position AND there aren't any rest args, this should be a tail call (I think)
                                    if rest.is_empty() && tail_pos {
                                        self.emit_op(Op::TailCall);
                                    } else {
                                        self.emit_op(Op::Call);
                                    }
                                    self.emit_byte(arity);
                                    self.stack_depth -= arity;
                                }
                            }
                        }
                    }
                    _ => unreachable!(),
                }
                // the last term in rest should be in tail position if we are in tail position
                let num_rest_terms = rest.len();
                for (i, (term, _)) in rest.iter().enumerate() {
                    match term {
                        Keyword(str) => {
                            self.emit_constant(Value::Keyword(str));
                            self.emit_op(Op::GetKey);
                            self.stack_depth -= 1;
                        }
                        Arguments(args) => {
                            self.emit_op(Op::Stash);
                            self.pop();
                            let arity = args.len();
                            for arg in args {
                                self.visit(arg);
                            }
                            self.emit_op(Op::Load);
                            if tail_pos && i == num_rest_terms - 1 {
                                self.emit_op(Op::TailCall)
                            } else {
                                self.emit_op(Op::Call);
                            }
                            self.emit_byte(arity);
                            self.stack_depth -= arity;
                        }
                        _ => unreachable!(),
                    }
                }
                self.tail_pos = tail_pos;
            }
            When(clauses) => {
                let tail_pos = self.tail_pos;
                let mut jump_idxes = vec![];
                let mut clauses = clauses.iter();
                while let Some((WhenClause(cond, body), _)) = clauses.next() {
                    self.tail_pos = false;
                    self.visit(cond.as_ref());
                    let jif_jump_idx = self.stub_jump(Op::JumpIfFalse);
                    self.stack_depth -= 1;
                    self.tail_pos = tail_pos;
                    self.visit(body);
                    self.stack_depth -= 1;
                    jump_idxes.push(self.stub_jump(Op::Jump));
                    self.patch_jump(jif_jump_idx, self.len() - jif_jump_idx - 3);
                }
                self.emit_op(Op::PanicNoWhen);
                for idx in jump_idxes {
                    self.patch_jump(idx, self.len() - idx - 3);
                }
                self.stack_depth += 1;
            }
            WhenClause(..) => unreachable!(),
            Match(scrutinee, clauses) => {
                let tail_pos = self.tail_pos;
                self.tail_pos = false;
                self.visit(scrutinee.as_ref());
                let stack_depth = self.stack_depth;
                let mut jump_idxes = vec![];
                let mut clauses = clauses.iter();
                while let Some((MatchClause(pattern, guard, body), _)) = clauses.next() {
                    self.tail_pos = false;
                    let mut no_match_jumps = vec![];
                    self.scope_depth += 1;
                    self.match_depth = 0;
                    self.visit(pattern);
                    no_match_jumps.push(self.stub_jump(Op::JumpIfNoMatch));
                    if guard.is_some() {
                        let guard_expr: &'static Spanned<Ast> =
                            Box::leak(Box::new(guard.clone().unwrap()));
                        self.visit(guard_expr);
                        no_match_jumps.push(self.stub_jump(Op::JumpIfFalse));
                        self.stack_depth -= 1;
                    }
                    self.tail_pos = tail_pos;
                    self.visit(body);
                    self.emit_op(Op::Store);
                    self.scope_depth -= 1;
                    while let Some(binding) = self.bindings.last() {
                        if binding.depth > self.scope_depth {
                            self.bindings.pop();
                        } else {
                            break;
                        }
                    }
                    self.pop_n(self.stack_depth - stack_depth);
                    jump_idxes.push(self.stub_jump(Op::Jump));
                    for idx in no_match_jumps {
                        self.patch_jump(idx, self.len() - idx - 3);
                    }
                }
                self.emit_op(Op::PanicNoMatch);

                for idx in jump_idxes {
                    self.patch_jump(idx, self.len() - idx - 3);
                }
                self.pop_n(self.stack_depth - stack_depth);
                self.emit_op(Op::Load);
                self.stack_depth += 1;
            }
            MatchClause(..) => unreachable!(),
            Fn(name, body, doc) => {
                let is_anon = name.is_empty();

                if !is_anon {
                    let declared = self.chunk.constants.iter().any(|val| match val {
                        Value::Fn(lfn) => lfn.name() == *name,
                        _ => false,
                    });
                    if !declared {
                        let declaration = Value::Fn(Rc::new(LFn::Declared { name }));
                        self.emit_constant(declaration);
                        self.bind(name);
                    }
                }

                let FnBody(fn_body) = &body.as_ref().0 else {
                    unreachable!()
                };

                let mut compilers: HashMap<u8, Compiler> = HashMap::new();

                let mut upvalues = vec![];

                let mut has_splat = false;

                for clause in fn_body {
                    let MatchClause(pattern, guard, clause_body) = &clause.0 else {
                        unreachable!()
                    };
                    let TuplePattern(pattern) = &pattern.0 else {
                        unreachable!()
                    };

                    if matches!(pattern.last(), Some((Splattern(_), _))) {
                        has_splat = true;
                    };

                    let arity = pattern.len() as u8;

                    let compiler = match compilers.get_mut(&arity) {
                        Some(compiler) => compiler,
                        None => {
                            let mut compiler = Compiler::new(
                                clause,
                                self.name,
                                self.src,
                                Some(self),
                                self.chunk.env.clone(),
                            );
                            compiler.emit_op(Op::ResetMatch);
                            compilers.insert(arity, compiler);
                            compilers.get_mut(&arity).unwrap()
                        }
                    };
                    compiler.tail_pos = false;

                    compiler.stack_depth += arity as usize;
                    compiler.scope_depth += 1;
                    compiler.match_depth = arity as usize;

                    std::mem::swap(&mut upvalues, &mut compiler.upvalues);

                    let mut tup_jump_idxes = vec![];
                    for member in pattern {
                        compiler.match_depth -= 1;
                        compiler.emit_op(Op::MatchDepth);
                        compiler.emit_byte(compiler.match_depth);
                        compiler.visit(member);
                        tup_jump_idxes.push(compiler.stub_jump(Op::JumpIfNoMatch));
                    }
                    if pattern.is_empty() {
                        compiler.emit_op(Op::Match);
                    }
                    let jump_idx = compiler.stub_jump(Op::Jump);
                    for idx in tup_jump_idxes {
                        compiler.patch_jump(idx, compiler.len() - idx - 3);
                    }
                    // compiler.emit_op(Op::PopN);
                    // compiler.emit_byte(arity as usize);
                    compiler.patch_jump(jump_idx, compiler.len() - jump_idx - 3);
                    let mut no_match_jumps = vec![];
                    no_match_jumps.push(compiler.stub_jump(Op::JumpIfNoMatch));
                    if guard.is_some() {
                        let guard_expr: &'static Spanned<Ast> =
                            Box::leak(Box::new(guard.clone().unwrap()));
                        compiler.visit(guard_expr);
                        no_match_jumps.push(compiler.stub_jump(Op::JumpIfFalse));
                        compiler.stack_depth -= 1;
                    }
                    compiler.tail_pos = true;
                    compiler.visit(clause_body);
                    compiler.emit_op(Op::Store);
                    compiler.scope_depth -= 1;
                    while let Some(binding) = compiler.bindings.last() {
                        if binding.depth > compiler.scope_depth {
                            compiler.bindings.pop();
                        } else {
                            break;
                        }
                    }
                    compiler.pop_n(compiler.stack_depth);
                    compiler.stack_depth = 0;
                    compiler.emit_op(Op::Return);
                    for idx in no_match_jumps {
                        compiler.patch_jump(idx, compiler.len() - idx - 3);
                    }
                    compiler.scope_depth -= 1;

                    std::mem::swap(&mut compiler.upvalues, &mut upvalues);
                }

                let mut compilers = compilers.into_iter().collect::<Vec<_>>();
                compilers.sort_by(|(a, _), (b, _)| a.cmp(b));

                let mut arities = vec![];
                let mut chunks = vec![];

                for (arity, mut compiler) in compilers {
                    compiler.emit_op(Op::PanicNoMatch);
                    let chunk = compiler.chunk;
                    if crate::DEBUG_COMPILE {
                        println!("=== function chuncktion: {name}/{arity} ===");
                        chunk.dissasemble();
                    }

                    arities.push(arity);
                    chunks.push(chunk);
                }

                let splat = if has_splat {
                    arities.iter().fold(0, |max, curr| max.max(*curr))
                } else {
                    0
                };

                let lfn = crate::value::LFn::Defined {
                    name,
                    doc: *doc,
                    arities,
                    chunks,
                    splat,
                    closed: RefCell::new(vec![]),
                };

                // TODO: check if the function is already declared, and pull out the relevant OnceCell if need be
                let the_fn = Value::Fn(Rc::new(lfn));
                // self.emit_constant(the_fn);
                // self.bind(name);

                if !is_anon {
                    let declaration_idx = self
                        .chunk
                        .constants
                        .iter()
                        .position(|val| match val {
                            Value::Fn(declaration) => declaration.name() == *name,
                            _ => false,
                        })
                        .unwrap();
                    self.chunk.constants[declaration_idx] = the_fn;
                } else {
                    self.emit_constant(the_fn)
                }

                for upvalue in upvalues {
                    self.emit_op(Op::SetUpvalue);
                    self.emit_byte(upvalue.stack_pos);
                }
            }
            FnDeclaration(name) => {
                let lfn = Value::Fn(Rc::new(LFn::Declared { name }));
                self.emit_constant(lfn);
                self.bind(name);
            }
            FnBody(_) => unreachable!(),
            Repeat(times, body) => {
                self.visit(times);
                self.emit_op(Op::Truncate);
                // skip the decrement the first time
                self.emit_op(Op::Jump);
                self.emit_byte(0);
                self.emit_byte(1);
                // begin repeat
                self.emit_op(Op::Decrement);
                let repeat_begin = self.len();
                self.emit_op(Op::Duplicate);
                let jiz_idx = self.stub_jump(Op::JumpIfZero);
                // compile the body
                self.visit(body);
                // pop whatever value the body returns
                self.pop();
                let jump_back = self.stub_jump(Op::JumpBack);
                // set jump points
                self.patch_jump(jump_back, self.len() - repeat_begin - 2);
                self.patch_jump(jiz_idx, self.len() - repeat_begin - 4);
                self.pop();
                self.emit_constant(Value::Nil);
            }
            Loop(value, clauses) => {
                let tail_pos = self.tail_pos;
                self.tail_pos = false;
                //algo:
                //first, put the values on the stack
                let (Ast::Tuple(members), _) = value.as_ref() else {
                    unreachable!()
                };
                for (i, member) in members.iter().enumerate() {
                    self.visit(member);
                    self.emit_op(Op::StoreAt);
                    self.emit_byte(i);
                }
                let arity = members.len();
                let stack_depth = self.stack_depth;
                //then, save the beginning of the loop
                self.emit_op(Op::Load);
                self.enter_loop();
                self.stack_depth += arity;
                //next, compile each clause:
                let mut clauses = clauses.iter();
                let mut jump_idxes = vec![];
                while let Some((Ast::MatchClause(pattern, guard, body), _)) = clauses.next() {
                    self.tail_pos = false;
                    self.emit_op(Op::ResetMatch);
                    self.scope_depth += 1;
                    let (Ast::TuplePattern(members), _) = pattern.as_ref() else {
                        unreachable!()
                    };
                    self.match_depth = arity;
                    let mut jnm_idxes = vec![];
                    for member in members {
                        self.match_depth -= 1;
                        self.emit_op(Op::MatchDepth);
                        self.emit_byte(self.match_depth);
                        self.visit(member);
                        jnm_idxes.push(self.stub_jump(Op::JumpIfNoMatch));
                    }
                    if guard.is_some() {
                        let guard_expr: &'static Spanned<Ast> =
                            Box::leak(Box::new(guard.clone().unwrap()));
                        self.visit(guard_expr);
                        jnm_idxes.push(self.stub_jump(Op::JumpIfFalse));
                        self.stack_depth -= 1;
                    }
                    self.tail_pos = tail_pos;
                    self.visit(body);
                    self.emit_op(Op::Store);
                    self.scope_depth -= 1;
                    while let Some(binding) = self.bindings.last() {
                        if binding.depth > self.scope_depth {
                            self.bindings.pop();
                        } else {
                            break;
                        }
                    }
                    while self.stack_depth > stack_depth {
                        self.pop();
                    }
                    jump_idxes.push(self.stub_jump(Op::Jump));
                    for idx in jnm_idxes {
                        self.patch_jump(idx, self.len() - idx - 3);
                    }
                    self.scope_depth -= 1;
                }
                self.emit_op(Op::PanicNoMatch);
                for idx in jump_idxes {
                    self.patch_jump(idx, self.len() - idx - 3);
                }
                self.stack_depth -= arity;
                self.emit_op(Op::Load);
                self.stack_depth += 1;
                self.leave_loop();
            }
            Recur(args) => {
                for (i, arg) in args.iter().enumerate() {
                    self.visit(arg);
                    self.emit_op(Op::StoreAt);
                    self.emit_byte(i);
                }
                self.emit_op(Op::PopN);
                self.emit_byte(self.loop_root());
                self.emit_op(Op::Load);
                self.jump(Op::JumpBack, self.len() - self.loop_idx());
            }
            Panic(msg) => {
                self.visit(msg);
                self.emit_op(Op::Panic);
            }
            Interpolated(parts) => {
                self.emit_op(Op::EmptyString);
                self.stack_depth += 1;
                for part in parts {
                    let str = &part.0;
                    match str {
                        StringPart::Inline(_) => unreachable!(),
                        StringPart::Data(str) => {
                            let allocated = Value::String(Rc::new(str.clone()));
                            self.emit_constant(allocated);
                            self.emit_op(Op::ConcatStrings);
                            self.stack_depth -= 1;
                        }
                        StringPart::Word(word) => {
                            self.resolve_binding(word);
                            self.emit_op(Op::Stringify);
                            self.emit_op(Op::ConcatStrings);
                        }
                    }
                }
            }
            Do(terms) => {
                let mut terms = terms.iter();
                let first = terms.next().unwrap();
                let mut terms = terms.rev();
                let last = terms.next().unwrap();
                let terms = terms.rev();
                // put the first value on the stack
                let tail_pos = self.tail_pos;
                self.tail_pos = false;
                self.visit(first);
                for term in terms {
                    self.visit(term);
                    self.emit_op(Op::Call);
                    self.emit_byte(1);
                    self.stack_depth -= 1;
                }
                self.visit(last);
                if tail_pos {
                    self.emit_op(Op::TailCall)
                } else {
                    self.emit_op(Op::Call);
                }
                self.emit_byte(1);
                self.tail_pos = tail_pos;
                self.stack_depth -= 1;
            }
            Placeholder => {
                self.emit_op(Op::Nothing);
            }
            And | Or | Arguments(..) => unreachable!(),
        }
    }

    pub fn disassemble(&self) {
        println!("=== chunk: {} ===", self.name);
        self.chunk.dissasemble();
    }
}