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Add double-stack words (2dup, 2drop, 2swap, 2over) and forget

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This commit is contained in:
Raphaël Forment
2026-02-02 07:46:39 +01:00
parent 3e8076e416
commit 2af0b67714
6 changed files with 186 additions and 0 deletions
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40
crates/forth/src/vm.rs
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@@ -262,6 +262,42 @@ impl Forth {
let v = stack[len - 1].clone();
stack.insert(len - 2, v);
}
Op::Dup2 => {
let len = stack.len();
if len < 2 {
return Err("stack underflow".into());
}
let a = stack[len - 2].clone();
let b = stack[len - 1].clone();
stack.push(a);
stack.push(b);
}
Op::Drop2 => {
let len = stack.len();
if len < 2 {
return Err("stack underflow".into());
}
stack.pop();
stack.pop();
}
Op::Swap2 => {
let len = stack.len();
if len < 4 {
return Err("stack underflow".into());
}
stack.swap(len - 4, len - 2);
stack.swap(len - 3, len - 1);
}
Op::Over2 => {
let len = stack.len();
if len < 4 {
return Err("stack underflow".into());
}
let a = stack[len - 4].clone();
let b = stack[len - 3].clone();
stack.push(a);
stack.push(b);
}
Op::Add => binary_op(stack, |a, b| a + b)?,
Op::Sub => binary_op(stack, |a, b| a - b)?,
@@ -915,6 +951,10 @@ impl Forth {
.unwrap_or(0);
stack.push(Value::Int(val as i64, None));
}
Op::Forget => {
let name = stack.pop().ok_or("stack underflow")?.as_str()?.to_string();
self.dict.lock().unwrap().remove(&name);
}
}
pc += 1;
}