c/crafting-interpreters
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[rlox] Make nil falsey + add equal and comparisons

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This commit is contained in:
ctsk
2023-10-09 13:47:46 +02:00
parent 8ea397881c
commit 90e70c4cd2
3 changed files with 67 additions and 42 deletions
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46
rlox/src/vm.rs
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@@ -95,19 +95,35 @@ impl VM {
self.push(new_val.into());
}
Op::Not => {
let new_val = !self.pop_bool()?;
let top_of_stack = self.pop()?;
let new_val = match top_of_stack {
Value::Nil => Ok(true),
Value::Bool(val) => Ok(!val),
_ => Err(self.type_err("Boolean or Nil", top_of_stack)),
}?;
self.push(new_val.into());
}
Op::Add | Op::Subtract | Op::Multiply | Op::Divide => {
let b = self.pop_num()?;
let a = self.pop_num()?;
let r = match instr {
Op::Add => Ok(a + b),
Op::Subtract => Ok(a - b),
Op::Multiply => Ok(a * b),
Op::Divide => Ok(a / b),
_ => Err(self.runtime_err("Op not implemented")),
}?;
Op::Add => a + b,
Op::Subtract => a - b,
Op::Multiply => a * b,
Op::Divide => a / b,
_ => unreachable!(),
};
self.push(r.into())
}
Op::Equal | Op::Greater | Op::Less => {
let b = self.pop()?;
let a = self.pop()?;
let r = match instr {
Op::Equal => a == b,
Op::Greater => a > b,
Op::Less => a < b,
_ => unreachable!(),
};
self.push(r.into())
}
}
@@ -123,6 +139,7 @@ impl VM {
#[cfg(test)]
mod tests {
use crate::bc::Op::Equal;
use super::{Chunk, Op, Value, VM};
use crate::vm::VMError;
@@ -177,7 +194,20 @@ mod tests {
#[test]
fn simple_booleans() {
let chunk = Chunk::new_with(
vec![Op::False, Op::Not],
vec![Op::False, Op::Not, Op::False, Op::Not, Op::Equal],
vec![],
vec![],
);
let mut vm = VM::new();
vm.run(&chunk).unwrap();
assert_eq!(vm.stack[0], true.into());
}
#[test]
fn not_nil_is_true() {
let chunk = Chunk::new_with(
vec![Op::Nil, Op::Not],
vec![],
vec![],
);