add rpush and rpop stack instructions

crsn_stacks/src/defs.rs

@@ -5,4 +5,6 @@ pub enum StackOp {
     NewStack { dst: Wr },
     Push { obj: RdObj, src: Rd },
     Pop { dst: Wr, obj: RdObj },
+    ReversePush { obj: RdObj, src: Rd },
+    ReversePop { dst: Wr, obj: RdObj },
 }

crsn_stacks/src/exec.rs

@@ -10,6 +10,7 @@ use crate::defs::StackOp;
 use crsn::sexp::Sexp;
 use crsn::sexp;
 use crsn::utils::A;
+use crsn::asm::data::{RdObj, Rd, Wr};
 
 #[derive(Debug, Default)]
 struct Stacks {
@@ -28,16 +29,57 @@ impl OpTrait for StackOp {
                 state.write(*dst, id)?;
             }
             StackOp::Push { obj, src } => {
+                prepare_push(state, obj, src,
+                             |stack, val| stack.push_back(val))?;
+            }
+            StackOp::ReversePush { obj, src } => {
+                prepare_push(state, obj, src,
+                             |stack, val| stack.push_front(val))?;
+            }
+            StackOp::Pop { dst, obj } => {
+                prepare_pop(state, dst, obj,
+                            |stack| stack.pop_back())?;
+            }
+            StackOp::ReversePop { dst, obj } => {
+                prepare_pop(state, dst, obj,
+                            |stack| stack.pop_front())?;
+            }
+        }
+
+        Ok(eres)
+    }
+
+    fn to_sexp(&self) -> Sexp {
+        match self {
+            StackOp::NewStack { dst } => sexp::list(&[A("stack"), A(dst)]),
+            StackOp::Push { obj, src } => sexp::list(&[A("push"), A(obj), A(src)]),
+            StackOp::Pop { dst, obj } => sexp::list(&[A("pop"), A(dst), A(obj)]),
+            StackOp::ReversePush { obj, src } => sexp::list(&[A("rpush"), A(obj), A(src)]),
+            StackOp::ReversePop { dst, obj } => sexp::list(&[A("rpop"), A(dst), A(obj)]),
+        }
+    }
+}
+
+
+pub(crate) fn drop_obj(state: &mut RunState, handle: Value) -> Result<Option<()>, Fault> {
+    let stacks: &mut Stacks = state.ext_mut();
+    Ok(stacks.store.remove(&handle).map(|_| ()))
+}
+
+fn prepare_push(mut state: &mut RunState, obj: &RdObj, src: &Rd, pushfn : impl FnOnce(&mut VecDeque<Value>, Value) -> ()) -> Result<(), Fault> {
     state.clear_status();
     let handle = state.read_obj(*obj)?;
     let val = state.read(*src)?;
 
     let stacks: &mut Stacks = state.ext_mut();
-                stacks.store.get_mut(&handle)
+    let mutable = stacks.store.get_mut(&handle)
-                    .ok_or_else(|| Fault::ObjectNotExist(handle))?
+        .ok_or_else(|| Fault::ObjectNotExist(handle))?;
-                    .push_back(val);
+
+    pushfn(mutable, val);
+    Ok(())
 }
-            StackOp::Pop { dst, obj } => {
+
+fn prepare_pop(state: &mut RunState, dst: &Wr, obj: &RdObj, popfn : impl FnOnce(&mut VecDeque<Value>) -> Option<Value>) -> Result<(), Fault> {
     state.clear_status();
     let handle = state.read_obj(*obj)?;
 
@@ -45,7 +87,7 @@ impl OpTrait for StackOp {
     let stack = stacks.store.get_mut(&handle)
         .ok_or_else(|| Fault::ObjectNotExist(handle))?;
 
-                let val = stack.pop_back();
+    let val = popfn(stack);
 
     if stack.is_empty() {
         state.set_flag(Cond::Zero, true);
@@ -62,22 +104,5 @@ impl OpTrait for StackOp {
     };
 
     state.write(*dst, val)?;
-            }
+    Ok(())
-        }
-
-        Ok(eres)
-    }
-
-    fn to_sexp(&self) -> Sexp {
-        match self {
-            StackOp::NewStack { dst } => sexp::list(&[A("stack"), A(dst)]),
-            StackOp::Push { obj, src } => sexp::list(&[A("push"), A(obj), A(src)]),
-            StackOp::Pop { dst, obj } => sexp::list(&[A("pop"), A(dst), A(obj)]),
-        }
-    }
-}
-
-pub(crate) fn drop_obj(state: &mut RunState, handle: Value) -> Result<Option<()>, Fault> {
-    let stacks: &mut Stacks = state.ext_mut();
-    Ok(stacks.store.remove(&handle).map(|_| ()))
 }

crsn_stacks/src/parse.rs

@@ -27,6 +27,20 @@ pub(crate) fn parse<'a>(keyword: &str, mut args: TokenParser<'a>) -> Result<Pars
             }
         }
 
+        "rpush" => {
+            StackOp::ReversePush {
+                obj: args.next_rdobj()?,
+                src: args.next_rd()?,
+            }
+        }
+
+        "rpop" => {
+            StackOp::ReversePop {
+                dst: args.next_wr()?,
+                obj: args.next_rdobj()?,
+            }
+        }
+
         _other => {
             return Ok(ParseRes::Unknown(args));
         }

examples/stacks.csn

@@ -10,5 +10,27 @@
     (pop r1 @r0)
     (cmp r1 1 (ne? (fault)))
 
+    ; test reverse push
+    (push @r0 1)
+    (push @r0 7)
+    (rpush @r0 8)
+
+    (pop r1 @r0)
+    (cmp r1 7 (ne? (fault)))
+
+    (pop r1 @r0)
+    (cmp r1 1 (ne? (fault)))
+
+    (pop r1 @r0)
+    (cmp r1 8 (ne? (fault)))
+
+    ; test reverse pop
+
+    (push @r0 1000)
+    (push @r0 2000)
+
+    (rpop r1 @r0)
+    (cmp r1 1000 (ne? (fault)))
+
     (drop @r0)
 )