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compile guards in match forms

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This commit is contained in:
Scott Richmond 2024-12-26 23:46:06 -05:00
parent cfe0b83192
commit f5965fdb44
2 changed files with 74 additions and 42 deletions
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88
src/compiler.rs
View File

@ -237,6 +237,15 @@ impl Compiler {
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()
}
fn bind(&mut self, name: &'static str) {
self.bindings.push(Binding {
name,
@ -303,15 +312,15 @@ impl Compiler {
}
If(cond, then, r#else) => {
self.visit(cond);
let jif_idx = self.chunk.bytecode.len();
let jif_idx = self.len();
self.emit_op(Op::JumpIfFalse);
self.chunk.bytecode.push(0xff);
self.emit_byte(0xff);
self.visit(then);
let jump_idx = self.chunk.bytecode.len();
let jump_idx = self.len();
self.emit_op(Op::Jump);
self.chunk.bytecode.push(0xff);
self.emit_byte(0xff);
self.visit(r#else);
let end_idx = self.chunk.bytecode.len();
let end_idx = self.len();
let jif_offset = jump_idx - jif_idx;
let jump_offset = end_idx - jump_idx - 2;
self.chunk.bytecode[jif_idx + 1] = jif_offset as u8;
@ -332,7 +341,7 @@ impl Compiler {
let biter = self.bindings.iter().enumerate().rev();
for (i, binding) in biter {
if binding.name == *name {
self.chunk.bytecode.push(i as u8);
self.emit_byte(i);
break;
}
}
@ -384,14 +393,14 @@ impl Compiler {
self.visit(member);
}
self.emit_op(Op::PushTuple);
self.chunk.bytecode.push(members.len() as u8);
self.emit_byte(members.len());
}
List(members) => {
for member in members {
self.visit(member);
}
self.emit_op(Op::PushList);
self.chunk.bytecode.push(members.len() as u8);
self.emit_byte(members.len());
}
LBox(name, expr) => {
self.visit(expr);
@ -403,7 +412,7 @@ impl Compiler {
self.visit(pair);
}
self.emit_op(Op::PushDict);
self.chunk.bytecode.push(pairs.len() as u8);
self.emit_byte(pairs.len());
}
Pair(key, value) => {
let existing_kw = self.chunk.keywords.iter().position(|kw| kw == key);
@ -445,18 +454,17 @@ impl Compiler {
while let Some((WhenClause(cond, body), _)) = clauses.next() {
self.visit(cond.as_ref());
self.emit_op(Op::JumpIfFalse);
let jif_jump_idx = self.chunk.bytecode.len();
self.chunk.bytecode.push(0xff);
let jif_jump_idx = self.len();
self.emit_byte(0xff);
self.visit(body);
self.emit_op(Op::Jump);
jump_idxes.push(self.chunk.bytecode.len());
self.chunk.bytecode.push(0xff);
self.chunk.bytecode[jif_jump_idx] =
self.chunk.bytecode.len() as u8 - jif_jump_idx as u8 - 1;
jump_idxes.push(self.len());
self.emit_byte(0xff);
self.chunk.bytecode[jif_jump_idx] = self.len() as u8 - jif_jump_idx as u8 - 1;
}
self.emit_op(Op::PanicNoWhen);
for idx in jump_idxes {
self.chunk.bytecode[idx] = self.chunk.bytecode.len() as u8 - idx as u8 + 1;
self.chunk.bytecode[idx] = self.len() as u8 - idx as u8 + 1;
}
}
WhenClause(..) => unreachable!(),
@ -465,12 +473,17 @@ impl Compiler {
let mut jump_idxes = vec![];
let mut clauses = clauses.iter();
// TODO: add guard checking
while let Some((MatchClause(pattern, _, body), _)) = clauses.next() {
while let Some((MatchClause(pattern, guard, body), _)) = clauses.next() {
self.scope_depth += 1;
self.visit(pattern);
self.emit_op(Op::JumpIfNoMatch);
let jnm_jump_idx = self.chunk.bytecode.len();
self.chunk.bytecode.push(0xff);
let jnm_jump_idx = self.len();
self.emit_byte(0xff);
if let Some(expr) = guard.as_ref() {
self.visit(expr);
self.emit_op(Op::JumpIfFalse);
let jif_idx = self.len();
self.emit_byte(0xff);
self.visit(body);
self.emit_op(Op::Store);
self.scope_depth -= 1;
@ -483,15 +496,34 @@ impl Compiler {
}
}
self.emit_op(Op::Jump);
jump_idxes.push(self.chunk.bytecode.len());
self.chunk.bytecode.push(0xff);
jump_idxes.push(self.len());
self.emit_byte(0xff);
self.chunk.bytecode[jnm_jump_idx] =
self.chunk.bytecode.len() as u8 - jnm_jump_idx as u8 - 1;
self.len() as u8 - jnm_jump_idx as u8 - 1;
self.chunk.bytecode[jif_idx] = self.len() as u8 - jif_idx as u8 - 1;
} else {
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.emit_op(Op::Pop);
self.bindings.pop();
} else {
break;
}
}
self.emit_op(Op::Jump);
jump_idxes.push(self.len());
self.emit_byte(0xff);
self.chunk.bytecode[jnm_jump_idx] =
self.len() as u8 - jnm_jump_idx as u8 - 1;
}
}
self.emit_op(Op::PanicNoMatch);
self.emit_op(Op::Load);
for idx in jump_idxes {
self.chunk.bytecode[idx] = self.chunk.bytecode.len() as u8 - idx as u8 + 2;
self.chunk.bytecode[idx] = self.len() as u8 - idx as u8;
}
}
MatchClause(..) => unreachable!(),
@ -534,21 +566,21 @@ impl Compiler {
self.emit_op(Op::Truncate);
// skip the decrement the first time
self.emit_op(Op::Jump);
self.chunk.bytecode.push(1);
self.emit_byte(1);
// begin repeat
self.emit_op(Op::Decrement);
let repeat_begin = self.chunk.bytecode.len();
let repeat_begin = self.len();
self.emit_op(Op::Duplicate);
self.emit_op(Op::JumpIfZero);
self.chunk.bytecode.push(0xff);
self.emit_byte(0xff);
// compile the body
self.visit(body);
// pop whatever value the body returns
self.emit_op(Op::Pop);
self.emit_op(Op::JumpBack);
// set jump points
let repeat_end = self.chunk.bytecode.len();
self.chunk.bytecode.push((repeat_end - repeat_begin) as u8);
let repeat_end = self.len();
self.emit_byte(repeat_end - repeat_begin);
self.chunk.bytecode[repeat_begin + 2] = (repeat_end - repeat_begin - 2) as u8;
// pop the counter
self.emit_op(Op::Pop);

6
src/main.rs
View File

@ -68,9 +68,9 @@ pub fn run(src: &'static str) {
pub fn main() {
let src = "
let foo = 4
repeat foo {
:foo
match :foo with {
:foo if true -> :oops
:foo if true -> :yay!
}
";
run(src);