rishi/scryer-prolog
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fix recursive calls to call/N

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This commit is contained in:
Mark Thom
2017-07-28 17:02:08 -06:00
parent 8a99b6d3bc
commit 3aa8780086
10 changed files with 955 additions and 2753 deletions
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137
src/prolog/machine.rs
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@@ -15,13 +15,17 @@ enum MachineMode {
Write
}
struct MachineState {
//TODO: probably.. the wrong solution. should integrate deeply with the WAM.
//type SpecialHandler<'a> = fn(&'a mut MachineState, bool, usize);
struct MachineState { //<'a> {
h: usize,
s: usize,
p: CodePtr,
b: usize,
b0: usize,
e: usize,
//special_handlers: HashMap<&'a Atom, SpecialHandler<'a>>,
num_of_args: usize,
cp: CodePtr,
fail: bool,
@@ -99,7 +103,7 @@ impl Machine {
pub fn failed(&self) -> bool {
self.ms.fail
}
pub fn add_fact(&mut self, fact: &Term, mut code: Code) {
if let Some(name) = fact.name() {
let p = self.code.len();
@@ -289,8 +293,8 @@ impl Machine {
pub fn submit_query<'a>(&mut self, code: Code, alloc_locs: AllocVarDict<'a>) -> EvalSession<'a>
{
let mut heap_locs = HashMap::new();
self.cached_query = Some(code);
self.cached_query = Some(code);
self.run_query(&alloc_locs, &mut heap_locs);
if self.failed() {
@@ -977,7 +981,76 @@ impl MachineState {
self.p = CodePtr::DirEntry(compiled_tl_index);
},
None => self.fail = true
};
};
}
fn dispatch_call_n(&mut self,
code_dir: &CodeDir,
name: Atom,
is_call: bool,
arity: &mut usize,
narity: usize)
-> bool
{
if name == "call" {
let new_pred = self.registers[1].clone();
for i in 2 .. *arity + narity {
self.registers[i-1] = self.registers[i].clone();
}
self.registers[*arity + narity - 1] = new_pred;
if *arity + narity - 1 > 0 {
*arity = *arity + narity - 1;
return true;
} else {
self.fail = true;
return false;
}
}
if is_call {
self.try_call_predicate(code_dir, name, *arity + narity - 1);
} else {
self.try_execute_predicate(code_dir, name, *arity + narity - 1);
}
false
}
fn execute_call_n(&mut self, code_dir: &CodeDir, is_call: bool, mut arity: usize)
{
loop {
let addr = self.deref(self.registers[arity].clone());
match self.store(addr) {
Addr::Str(a) => {
let result = self.heap[a].clone();
if let HeapCellValue::NamedStr(narity, name) = result {
for i in (1 .. arity).rev() {
self.registers[i + narity] = self.registers[i].clone();
}
for i in 1 .. narity + 1 {
self.registers[i] = self.heap[a + i].as_addr(a + i);
}
if self.dispatch_call_n(code_dir, name, is_call, &mut arity, narity) {
continue;
}
}
},
Addr::Con(Constant::Atom(name)) =>
if self.dispatch_call_n(code_dir, name, is_call, &mut arity, 0) {
continue;
},
_ => self.fail = true
};
break;
}
}
fn execute_ctrl_instr(&mut self, code_dir: &CodeDir, instr: &ControlInstruction)
@@ -987,35 +1060,14 @@ impl MachineState {
let num_frames = self.num_frames();
self.and_stack.push(num_frames + 1, self.e, self.cp, num_cells);
self.e = self.and_stack.len() - 1;
self.p += 1;
},
&ControlInstruction::Call(ref name, arity, _) =>
self.try_call_predicate(code_dir, name.clone(), arity),
&ControlInstruction::CallN(arity) => {
let addr = self.deref(self.registers[arity].clone());
match self.store(addr) {
Addr::Str(a) => {
let result = self.heap[a].clone();
if let HeapCellValue::NamedStr(narity, name) = result {
for i in 1 .. narity + 1 {
self.registers[i + narity] = self.registers[i].clone();
self.registers[i] = self.heap[a + i].as_addr(a + i);
}
self.try_call_predicate(code_dir, name, arity + narity - 1);
} else {
self.fail = true;
}
},
Addr::Con(Constant::Atom(name)) =>
self.try_call_predicate(code_dir, name, arity - 1),
_ => self.fail = true
};
},
&ControlInstruction::CallN(arity) =>
self.execute_call_n(code_dir, true, arity),
&ControlInstruction::Deallocate => {
let e = self.e;
@@ -1025,30 +1077,9 @@ impl MachineState {
self.p += 1;
},
&ControlInstruction::Execute(ref name, arity) =>
self.try_execute_predicate(code_dir, name.clone(), arity),
&ControlInstruction::ExecuteN(arity) => {
let addr = self.deref(self.registers[arity].clone());
match self.store(addr) {
Addr::Str(a) => {
let result = self.heap[a].clone();
if let HeapCellValue::NamedStr(narity, name) = result {
for i in 1 .. narity + 1 {
self.registers[i + narity] = self.registers[i].clone();
self.registers[i] = self.heap[a + i].as_addr(a + i);
}
self.try_execute_predicate(code_dir, name, arity + narity - 1);
} else {
self.fail = true;
}
},
Addr::Con(Constant::Atom(name)) =>
self.try_execute_predicate(code_dir, name, arity - 1),
_ => self.fail = true
};
},
self.try_execute_predicate(code_dir, name.clone(), arity),
&ControlInstruction::ExecuteN(arity) =>
self.execute_call_n(code_dir, false, arity),
&ControlInstruction::Proceed =>
self.p = self.cp,
};