slvm/vm/cons.rs
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use crate::{decode2, decode3, decode_u16, set_register, GVm, VMError, VMResult, Value};
impl<ENV> GVm<ENV> {
pub(super) fn list(&mut self, wide: bool) -> VMResult<()> {
let (dest, start, end) = decode3!(self.ip_ptr, wide);
if end < start {
set_register!(self, dest as usize, Value::Nil);
} else {
let mut last_cdr = Value::Nil;
for i in (start..=end).rev() {
let car = self.register_unref(i as usize);
let cdr = last_cdr;
last_cdr = self.alloc_pair(car, cdr);
}
set_register!(self, dest as usize, last_cdr);
}
Ok(())
}
pub(super) fn append(&mut self, wide: bool) -> VMResult<()> {
let (dest, start, end) = decode3!(self.ip_ptr, wide);
if end < start {
set_register!(self, dest as usize, Value::Nil);
} else {
let mut last_cdr = Value::Nil;
let mut head = Value::Nil;
let mut loop_cdr;
for i in start..=end {
let lst = self.register_unref(i as usize);
match lst {
Value::Nil => {}
Value::Pair(_) | Value::List(_, _) => {
let (car, cdr) = lst.get_pair(self).expect("Pair/List not a Pair or List?");
loop_cdr = cdr;
let cdr = last_cdr;
last_cdr = self.alloc_pair(car, Value::Nil);
match cdr {
Value::Nil => head = last_cdr,
Value::Pair(h) => {
let (_, cdr) = self.get_pair_mut(h)?;
*cdr = last_cdr;
}
Value::List(_, _) => {
return Err(VMError::new_heap("Pair is not mutable!"))
}
_ => {}
}
loop {
if let Value::Nil = loop_cdr {
break;
}
match loop_cdr {
Value::Pair(_) | Value::List(_, _) => {
let (car, ncdr) = loop_cdr
.get_pair(self)
.expect("Pair/List not a Pair or List?");
loop_cdr = ncdr;
let cdr = last_cdr;
last_cdr = self.alloc_pair(car, Value::Nil);
match cdr {
Value::Nil => head = last_cdr,
Value::Pair(h) => {
let (_, cdr) = self.get_pair_mut(h)?;
*cdr = last_cdr;
}
Value::List(_, _) => {
return Err(VMError::new_heap("Pair is not mutable!"))
}
_ => {}
}
}
_ => {
if i == end {
match last_cdr {
Value::Nil => head = loop_cdr,
Value::Pair(h) => {
let (_, cdr) = self.get_pair_mut(h)?;
*cdr = loop_cdr;
}
Value::List(_, _) => {
return Err(VMError::new_heap(
"Pair is not mutable!",
))
}
_ => {}
}
} else {
return Err(VMError::new_vm("APND: Param not a list."));
}
break;
}
}
}
}
_ => {
if i == end {
match last_cdr {
Value::Nil => head = lst,
Value::Pair(h) => {
let (_, cdr) = self.get_pair_mut(h)?;
*cdr = lst;
}
Value::List(_, _) => {
return Err(VMError::new_heap("Pair is not mutable!"))
}
_ => {}
}
} else {
return Err(VMError::new_vm("APND: Param not a list."));
}
}
}
}
set_register!(self, dest as usize, head);
}
Ok(())
}
pub(super) fn xar(&mut self, wide: bool) -> VMResult<()> {
let (pair_reg, val) = decode2!(self.ip_ptr, wide);
let pair = self.register_unref(pair_reg as usize);
let val = self.register_unref(val as usize);
match &pair {
Value::Pair(handle) => {
let (car, _) = self.get_pair_mut(*handle)?;
*car = val;
}
Value::List(_, _) => return Err(VMError::new_vm("XAR: Pair is read only.")),
_ => return Err(VMError::new_vm("XAR: Not a pair/conscell.")),
}
Ok(())
}
pub(super) fn xdr(&mut self, wide: bool) -> VMResult<()> {
let (pair_reg, val) = decode2!(self.ip_ptr, wide);
let pair = self.register_unref(pair_reg as usize);
let val = self.register_unref(val as usize);
match &pair {
Value::Pair(handle) => {
let (_, cdr) = self.get_pair_mut(*handle)?;
*cdr = val;
}
Value::List(_, _) => return Err(VMError::new_vm("XDR: Pair is read only.")),
_ => return Err(VMError::new_vm("XDR: Not a pair/conscell.")),
}
Ok(())
}
}