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expr.rs
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use crate::s;
use super::Parser;
use super::types::{OpCode, Value, MAX_EXPR_DEPTH, Instruction};
use super::types::{parse_string, parse_bytes_literal};
use crate::modules::lexer::{Token, TokenType};
use alloc::{string::ToString, vec::Vec, string::String};
impl<'src, I: Iterator<Item = Token>> Parser<'src, I> {
/* Entry: recursion guard, Pratt parse, then optional ternary. */
pub(super) fn expr(&mut self) {
self.expr_depth += 1;
if self.expr_depth > MAX_EXPR_DEPTH {
self.expr_depth -= 1;
self.error("expression too deeply nested");
return;
}
self.saw_newline = false;
self.expr_bp(0);
if !self.saw_newline && matches!(self.peek(), Some(TokenType::If)) {
self.advance();
self.expr_bp(0);
self.chunk.emit(OpCode::JumpIfFalse, 0);
let jf = self.chunk.instructions.len() - 1;
self.chunk.emit(OpCode::Jump, 0);
let jmp = self.chunk.instructions.len() - 1;
self.patch(jf);
self.chunk.emit(OpCode::PopTop, 0);
self.eat(TokenType::Else);
self.expr_bp(0);
self.patch(jmp);
}
self.expr_depth -= 1;
}
pub(super) fn expr_tails(&mut self) {
self.postfix_tail();
self.infix_bp(0);
}
/* Pratt parser: unary prefix then infix loop via `binding_power` table. */
pub(super) fn expr_bp(&mut self, min_bp: u8) {
match self.peek() {
Some(TokenType::Not) => {
self.advance();
self.expr_bp(5);
self.chunk.emit(OpCode::Not, 0);
}
_ => self.parse_unary(),
}
self.infix_bp(min_bp);
}
pub(super) fn infix_bp(&mut self, min_bp: u8) {
while let Some(tok) = self.peek() {
if tok == TokenType::Is {
if 7 < min_bp { break; }
self.advance();
if self.eat_if(TokenType::Not) {
self.expr_bp(8);
self.chunk.emit(OpCode::IsNot, 0);
} else {
self.expr_bp(8);
self.chunk.emit(OpCode::Is, 0);
}
continue;
}
if tok == TokenType::Not {
if 7 < min_bp { break; }
self.advance();
self.eat(TokenType::In);
self.expr_bp(8);
self.chunk.emit(OpCode::NotIn, 0);
continue;
}
let Some((l_bp, r_bp, op)) = Self::binding_power(&tok) else { break };
if l_bp < min_bp { break; }
self.advance();
if matches!(op, OpCode::And | OpCode::Or) {
let jump_op = if op == OpCode::And { OpCode::JumpIfFalseOrPop } else { OpCode::JumpIfTrueOrPop };
self.chunk.emit(jump_op, 0);
let jmp = self.chunk.instructions.len() - 1;
self.expr_bp(r_bp);
self.patch(jmp);
continue;
}
self.expr_bp(r_bp);
if matches!(op, OpCode::Eq | OpCode::NotEq | OpCode::Lt | OpCode::Gt | OpCode::LtEq | OpCode::GtEq)
&& let Some(next_tok) = self.peek()
&& matches!(next_tok, TokenType::Less | TokenType::Greater | TokenType::LessEqual | TokenType::GreaterEqual | TokenType::EqEqual | TokenType::NotEqual)
{
let ver = self.increment_version(super::SSA_TMP_CMP);
let tmp = self.push_ssa_name(super::SSA_TMP_CMP, ver);
self.chunk.emit(OpCode::StoreName, tmp);
self.chunk.emit(OpCode::LoadName, tmp);
self.chunk.emit(op, 0);
self.chunk.emit(OpCode::JumpIfFalseOrPop, 0);
let jmp = self.chunk.instructions.len() - 1;
self.chunk.emit(OpCode::LoadName, tmp);
self.infix_bp(min_bp);
self.patch(jmp);
return;
}
self.chunk.emit(op, 0);
}
}
pub(super) fn binding_power(tok: &TokenType) -> Option<(u8, u8, OpCode)> {
match tok {
TokenType::Or => Some((1, 2, OpCode::Or)),
TokenType::And => Some((3, 4, OpCode::And)),
TokenType::EqEqual => Some((7, 8, OpCode::Eq)),
TokenType::NotEqual => Some((7, 8, OpCode::NotEq)),
TokenType::Less => Some((7, 8, OpCode::Lt)),
TokenType::Greater => Some((7, 8, OpCode::Gt)),
TokenType::LessEqual => Some((7, 8, OpCode::LtEq)),
TokenType::GreaterEqual => Some((7, 8, OpCode::GtEq)),
TokenType::In => Some((7, 8, OpCode::In)),
TokenType::Vbar => Some((9, 10, OpCode::BitOr)),
TokenType::Circumflex => Some((11, 12, OpCode::BitXor)),
TokenType::Amper => Some((13, 14, OpCode::BitAnd)),
TokenType::LeftShift => Some((15, 16, OpCode::Shl)),
TokenType::RightShift => Some((15, 16, OpCode::Shr)),
TokenType::Plus => Some((17, 18, OpCode::Add)),
TokenType::Minus => Some((17, 18, OpCode::Sub)),
TokenType::Star => Some((19, 20, OpCode::Mul)),
TokenType::Slash => Some((19, 20, OpCode::Div)),
TokenType::Percent => Some((19, 20, OpCode::Mod)),
TokenType::DoubleSlash => Some((19, 20, OpCode::FloorDiv)),
TokenType::DoubleStar => Some((22, 21, OpCode::Pow)),
_ => None,
}
}
pub(super) fn parse_unary(&mut self) {
match self.peek() {
Some(TokenType::Minus) => {
self.advance();
self.expr_bp(21);
self.chunk.emit(OpCode::Minus, 0);
}
Some(TokenType::Tilde) => {
self.advance();
self.expr_bp(21);
self.chunk.emit(OpCode::BitNot, 0);
}
Some(TokenType::Await) => {
self.advance();
self.expr_bp(21);
self.chunk.emit(OpCode::Await, 0);
}
_ => self.parse_atom()
}
}
/* Atoms: literals, names, numbers, strings, f-strings, containers. */
pub(super) fn parse_atom(&mut self) {
let errs_before = self.errors.len();
let t = self.advance();
match t.kind {
TokenType::Name => self.name(t),
TokenType::String => {
let mut s = parse_string(self.lexeme(&t));
while matches!(self.peek(), Some(TokenType::String)) {
let t = self.advance();
s.push_str(&parse_string(self.lexeme(&t)));
}
self.emit_const(Value::Str(s));
}
TokenType::Bytes => {
// Adjacent bytes literals concat; mixing with str surfaces a diagnostic.
let mut buf = parse_bytes_literal(self.lexeme(&t));
while matches!(self.peek(), Some(TokenType::Bytes)) {
let t = self.advance();
buf.extend_from_slice(&parse_bytes_literal(self.lexeme(&t)));
}
self.emit_const(Value::Bytes(buf));
}
TokenType::Int | TokenType::Float => {
self.parse_number(self.lexeme(&t), t.kind);
}
TokenType::True => self.chunk.emit(OpCode::LoadTrue, 0),
TokenType::False => self.chunk.emit(OpCode::LoadFalse, 0),
TokenType::None => self.chunk.emit(OpCode::LoadNone, 0),
TokenType::Ellipsis => self.chunk.emit(OpCode::LoadEllipsis, 0),
TokenType::FstringStart => self.fstring(t.start, t.end),
TokenType::Lbrace => self.brace_literal(),
TokenType::Lsqb => self.list_literal(),
TokenType::Lpar => {
if matches!(self.peek(), Some(TokenType::Rpar)) {
self.advance();
self.chunk.emit(OpCode::BuildTuple, 0);
} else {
let elem_start = self.chunk.instructions.len();
self.expr();
if matches!(self.peek(), Some(TokenType::For)) {
let versions_before = self.ssa_versions.clone();
let elem_ins: Vec<Instruction> = self.chunk.instructions.drain(elem_start..).collect();
self.chunk.emit(OpCode::BuildList, 0);
self.comprehension_loop(&[elem_ins], OpCode::ListAppend, &versions_before);
self.advance();
} else if self.eat_if(TokenType::Comma) {
let mut count = 1u16;
while !matches!(self.peek(), Some(TokenType::Rpar) | None) {
self.expr();
count += 1;
if !self.eat_if(TokenType::Comma) { break; }
}
self.eat(TokenType::Rpar);
self.chunk.emit(OpCode::BuildTuple, count);
} else {
self.eat(TokenType::Rpar);
}
}
}
TokenType::Lambda => self.parse_lambda(),
// Caret at consumed token; skip if `advance()` already reported the error.
_ => {
if self.errors.len() == errs_before {
self.error_at(t.start, t.end, "expected expression");
}
}
}
self.postfix_tail();
}
/* Name: assignment, walrus `:=`, call, or plain load. */
pub(super) fn name(&mut self, t: Token) {
let name = self.lexeme(&t).to_string();
match self.peek() {
// In f-string context, `=` is the debug marker `f"{x=}"`, not assignment.
Some(TokenType::Equal) if !self.in_fstring_expr => {
self.assign(name.clone());
self.emit_load_ssa(name);
}
Some(TokenType::ColonEqual) => {
self.advance();
self.expr();
let ver = self.increment_version(&name);
let i = self.push_ssa_name(&name, ver);
self.chunk.emit(OpCode::StoreName, i);
self.chunk.emit(OpCode::LoadName, i);
}
Some(TokenType::Lpar) => {
let _ = self.call(name);
}
_ => self.emit_load_ssa(name),
}
self.postfix_tail();
}
fn parse_int_prefix(s: &str) -> (&str, u32) {
if let Some(h) = s.strip_prefix("0x").or_else(|| s.strip_prefix("0X")) { (h, 16) }
else if let Some(o) = s.strip_prefix("0o").or_else(|| s.strip_prefix("0O")) { (o, 8) }
else if let Some(b) = s.strip_prefix("0b").or_else(|| s.strip_prefix("0B")) { (b, 2) }
else { (s, 10) }
}
pub(super) fn parse_number(&mut self, raw: &str, kind: TokenType) {
let s = raw.replace('_', "");
if kind == TokenType::Float { self.emit_const(Value::Float(s.parse().unwrap_or(0.0))); return; }
let (digits, base) = Self::parse_int_prefix(&s);
let parsed_i64 = if base == 10 {
digits.parse::<i64>().ok()
} else {
i64::from_str_radix(digits, base).ok()
};
if let Some(v) = parsed_i64 {
self.emit_const(Value::Int(v));
return;
}
// Doesn't fit in i64, try i128 for the wide-int path.
let parsed_i128 = if base == 10 {
digits.parse::<i128>().ok()
} else {
i128::from_str_radix(digits, base).ok()
};
match parsed_i128 {
Some(v) => self.emit_const(Value::LongInt(v)),
None => self.error("integer literal too large to represent (max ±2^127)"),
}
}
/* Postfix trailers: `.attr`, [i], [s:e], (args), chained. A trailer must start on the same line, so a statement boundary ends the chain (else `x = []` ⏎ `[i]` parses as `[][i]`). */
pub(super) fn postfix_tail(&mut self) {
loop {
match self.peek_same_line() {
Some(TokenType::Lsqb) => {
self.advance();
let is_slice = matches!(self.peek(), Some(TokenType::Colon));
if is_slice {
self.chunk.emit(OpCode::LoadNone, 0);
} else {
self.expr();
}
if self.eat_if(TokenType::Colon) {
let mut parts = 2u16;
if matches!(self.peek(), Some(TokenType::Colon | TokenType::Rsqb)) {
self.chunk.emit(OpCode::LoadNone, 0);
} else {
self.expr();
}
if self.eat_if(TokenType::Colon) {
parts = 3;
if matches!(self.peek(), Some(TokenType::Rsqb)) {
self.chunk.emit(OpCode::LoadNone, 0);
} else {
self.expr();
}
}
self.eat(TokenType::Rsqb);
self.chunk.emit(OpCode::BuildSlice, parts);
// Slice assignment: StoreItem with Slice index; runtime replaces the range.
if matches!(self.peek(), Some(TokenType::Equal)) {
self.advance();
self.expr();
self.chunk.emit(OpCode::StoreItem, 0);
self.chunk.emit(OpCode::LoadNone, 0);
return;
}
self.chunk.emit(OpCode::GetItem, 0);
} else {
self.eat(TokenType::Rsqb);
if !is_slice && matches!(self.peek(), Some(TokenType::Equal)) {
self.advance();
self.expr();
self.chunk.emit(OpCode::StoreItem, 0);
self.chunk.emit(OpCode::LoadNone, 0);
return;
}
self.chunk.emit(OpCode::GetItem, 0);
}
}
Some(TokenType::Dot) => {
self.advance();
let t = self.advance();
let (start, end) = (t.start, t.end);
let idx = self.chunk.push_name(&self.source[start..end]);
// LoadAttr adjacent to Call lets `fuse_method_calls` collapse them.
self.chunk.emit(OpCode::LoadAttr, idx);
}
Some(TokenType::Lpar) => {
// Call after any trailer.
let call_pos = self.last_end as u32;
let (pos, kw) = self.parse_args();
let encoded = ((kw & 0xFF) << 8) | (pos & 0xFF);
self.chunk.emit(OpCode::Call, encoded);
self.chunk.record_call_pos(call_pos);
}
_ => break
}
}
}
/* lambda: fresh chunk, compiles body to Return, emits MakeFunction. */
pub(super) fn parse_lambda(&mut self) {
let mut params = Vec::new();
let mut defaults = 0u16;
if !matches!(self.peek(), Some(TokenType::Colon)) {
loop {
// Match parse_params prefix detection so *args/**kw names align with ParamKind.
let prefix = if self.eat_if(TokenType::DoubleStar) { "**" }
else if self.eat_if(TokenType::Star) { "*" }
else { "" };
let nm = self.advance_text();
params.push(if prefix.is_empty() { nm } else { s!(str prefix, str &nm) });
if prefix.is_empty() && self.eat_if(TokenType::Equal) {
self.expr();
defaults += 1;
}
if !self.eat_if(TokenType::Comma) {
break;
}
}
}
self.eat(TokenType::Colon);
let outer_versions = self.ssa_versions.clone();
let body = self.with_fresh_chunk(|s| {
s.ssa_versions = outer_versions;
for p in ¶ms { s.ssa_versions.insert(p.clone(), 0); }
s.expr();
s.chunk.emit(OpCode::ReturnValue, 0);
});
let param_slots: crate::util::fx::FxHashSet<String> = params.iter().map(|p| s!(str p.trim_start_matches('*'), "_0")).collect();
for name in &body.names {
if !param_slots.contains(name.as_str()) {
self.chunk.push_name(name);
}
}
let fi = self.chunk.functions.len() as u16;
self.chunk.functions.push((params, body, defaults, u16::MAX));
self.chunk.emit(OpCode::MakeFunction, fi);
}
}