From 69b4bbeeaef26f03223b427c6c643c8d09097398 Mon Sep 17 00:00:00 2001
From: Philip Monk <phil@pcmonk.me>
Date: Wed, 1 Feb 2023 20:59:17 -0700
Subject: [PATCH] add naive jet dashboard with two jets

---
 rust/ares/src/interpreter.rs | 15 ++++++++
 rust/ares/src/jets.rs        | 68 ++++++++++++++++++++++++++++++++++++
 rust/ares/src/lib.rs         |  1 +
 3 files changed, 84 insertions(+)
 create mode 100644 rust/ares/src/jets.rs

diff --git a/rust/ares/src/interpreter.rs b/rust/ares/src/interpreter.rs
index 6604d45..bb086b4 100644
--- a/rust/ares/src/interpreter.rs
+++ b/rust/ares/src/interpreter.rs
@@ -1,4 +1,5 @@
 use self::NockWork::*;
+use crate::jets::get_jet;
 use crate::mem::unifying_equality;
 use crate::mem::NockStack;
 use crate::noun::{Atom, Cell, DirectAtom, IndirectAtom, Noun};
@@ -312,6 +313,20 @@ pub fn interpret(stack: &mut NockStack, mut subject: Noun, formula: Noun) -> Nou
             Nock11ComputeHint => unsafe {
                 let hint = *stack.local_noun_pointer(1);
                 if let Ok(hint_cell) = hint.as_cell() {
+                    if hint_cell
+                        .head()
+                        .raw_equals(DirectAtom::new_unchecked(0x706f7270).as_noun())
+                    {
+                        if let Ok(jet_formula) = hint_cell.tail().as_cell() {
+                            let jet_name = jet_formula.tail();
+                            let jet = get_jet(jet_name);
+                            if let Ok(jet) = jet {
+                                res = jet(stack, subject);
+                                stack.pop(&mut res);
+                                continue;
+                            }
+                        }
+                    }
                     *(stack.local_noun_pointer(0)) = work_to_noun(Nock11ComputeResult);
                     push_formula(stack, hint_cell.tail());
                 } else {
diff --git a/rust/ares/src/jets.rs b/rust/ares/src/jets.rs
new file mode 100644
index 0000000..91882e7
--- /dev/null
+++ b/rust/ares/src/jets.rs
@@ -0,0 +1,68 @@
+use crate::interpreter::raw_slot;
+use crate::mem::NockStack;
+use crate::noun::{DirectAtom, IndirectAtom, Noun};
+use either::Either::*;
+
+pub fn get_jet(jet_name: Noun) -> Result<fn(&mut NockStack, Noun) -> Noun, ()> {
+    if let Ok(jet_direct) = jet_name.as_direct() {
+        match jet_direct.data() {
+            0x636564 => Ok(jet_dec),
+            0x747563 => Ok(jet_cut),
+            _ => Err(()),
+        }
+    } else {
+        Err(())
+    }
+}
+
+fn jet_dec(stack: &mut NockStack, subject: Noun) -> Noun {
+    let arg = raw_slot(subject, 6);
+    if let Ok(atom) = arg.as_atom() {
+        match atom.as_either() {
+            Left(direct) => {
+                if direct.data() == 0 {
+                    panic!("Decrementing 0");
+                } else {
+                    unsafe { DirectAtom::new_unchecked(direct.data() - 1) }.as_noun()
+                }
+            }
+            Right(indirect) => {
+                let indirect_slice = indirect.as_bitslice();
+                match indirect_slice.first_one() {
+                    None => {
+                        panic!("Decrementing 0");
+                    }
+                    Some(first_one) => {
+                        let (mut new_indirect, new_slice) =
+                            unsafe { IndirectAtom::new_raw_mut_bitslice(stack, indirect.size()) };
+                        if first_one > 0 {
+                            new_slice[..first_one].fill(true);
+                        }
+                        new_slice.set(first_one, false);
+                        new_slice[first_one + 1..]
+                            .copy_from_bitslice(&indirect_slice[first_one + 1..]);
+                        let res = unsafe { new_indirect.normalize_as_atom() };
+                        res.as_noun()
+                    }
+                }
+            }
+        }
+    } else {
+        panic!("Argument to dec must be atom");
+    }
+}
+
+fn jet_cut(stack: &mut NockStack, subject: Noun) -> Noun {
+    let arg = raw_slot(subject, 6);
+    let bloq = raw_slot(arg, 2).as_direct().unwrap().data();
+    let start = raw_slot(arg, 12).as_direct().unwrap().data();
+    let run = raw_slot(arg, 13).as_direct().unwrap().data();
+    let atom = raw_slot(arg, 7).as_atom().unwrap();
+    let slice = atom.as_bitslice();
+    let unit = 1 << bloq;
+    let (mut new_indirect, new_slice) =
+        unsafe { IndirectAtom::new_raw_mut_bitslice(stack, ((run * unit + 63) >> 6) as usize) };
+    new_slice[..(unit * run) as usize]
+        .copy_from_bitslice(&slice[(unit * start) as usize..(unit * (start + run)) as usize]);
+    unsafe { new_indirect.normalize_as_atom().as_noun() }
+}
diff --git a/rust/ares/src/lib.rs b/rust/ares/src/lib.rs
index 55d0089..c70f0b7 100644
--- a/rust/ares/src/lib.rs
+++ b/rust/ares/src/lib.rs
@@ -1,6 +1,7 @@
 #[macro_use]
 extern crate num_derive;
 pub mod interpreter;
+pub mod jets;
 pub mod mem;
 pub mod mug;
 pub mod noun;