From e3e0473b6933cd3bb98d939bef61242501c6a497 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Mon, 1 Apr 2019 09:04:50 -0600
Subject: [PATCH] fix term_variables, add (^)/2 as an actual evaluable functor

---
 src/prolog/arithmetic.rs                 |  3 ++-
 src/prolog/instructions.rs               |  1 +
 src/prolog/machine/machine_state_impl.rs | 10 +++++++++-
 src/prolog/machine/system_calls.rs       |  3 +--
 src/prolog/write.rs                      |  4 +++-
 5 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/prolog/arithmetic.rs b/src/prolog/arithmetic.rs
index 8cb0a8e1..d5e5246c 100644
--- a/src/prolog/arithmetic.rs
+++ b/src/prolog/arithmetic.rs
@@ -131,7 +131,8 @@ impl<'a> ArithmeticEvaluator<'a>
             "div"  => Ok(ArithmeticInstruction::FIDiv(a1, a2, t)),
             "rdiv" => Ok(ArithmeticInstruction::RDiv(a1, a2, t)),
             "*"    => Ok(ArithmeticInstruction::Mul(a1, a2, t)),
-            "**"    => Ok(ArithmeticInstruction::Pow(a1, a2, t)),
+            "**"   => Ok(ArithmeticInstruction::Pow(a1, a2, t)),
+            "^"    => Ok(ArithmeticInstruction::IntPow(a1, a2, t)),
             ">>"   => Ok(ArithmeticInstruction::Shr(a1, a2, t)),
             "<<"   => Ok(ArithmeticInstruction::Shl(a1, a2, t)),
             "/\\"  => Ok(ArithmeticInstruction::And(a1, a2, t)),
diff --git a/src/prolog/instructions.rs b/src/prolog/instructions.rs
index 1d5c42af..826cf93b 100644
--- a/src/prolog/instructions.rs
+++ b/src/prolog/instructions.rs
@@ -59,6 +59,7 @@ pub enum ArithmeticInstruction {
     Sub(ArithmeticTerm, ArithmeticTerm, usize),
     Mul(ArithmeticTerm, ArithmeticTerm, usize),
     Pow(ArithmeticTerm, ArithmeticTerm, usize),
+    IntPow(ArithmeticTerm, ArithmeticTerm, usize),
     IDiv(ArithmeticTerm, ArithmeticTerm, usize),
     Max(ArithmeticTerm, ArithmeticTerm, usize),
     FIDiv(ArithmeticTerm, ArithmeticTerm, usize),
diff --git a/src/prolog/machine/machine_state_impl.rs b/src/prolog/machine/machine_state_impl.rs
index 69e12db6..8aac7e2b 100644
--- a/src/prolog/machine/machine_state_impl.rs
+++ b/src/prolog/machine/machine_state_impl.rs
@@ -714,6 +714,7 @@ impl MachineState {
                         "*" => interms.push(a1 * a2),
                         "/" => interms.push(self.div(a1, a2)?),
                         "**" => interms.push(self.pow(a1, a2)?),
+                        "^"  => interms.push(self.pow(a1, a2)?),
                         "max"  => interms.push(self.max(a1, a2)?),
                         "rdiv" => {
                             let r1 = self.get_rational(&ArithmeticTerm::Number(a1), &caller)?;
@@ -1009,13 +1010,20 @@ impl MachineState {
                 self.interms[t - 1] = try_or_fail!(self, self.max(n1, n2));
                 self.p += 1;
             },
-            &ArithmeticInstruction::Pow(ref a1, ref a2, t) => {
+            &ArithmeticInstruction::IntPow(ref a1, ref a2, t) => {
                 let n1 = try_or_fail!(self, self.get_number(a1));
                 let n2 = try_or_fail!(self, self.get_number(a2));
 
                 self.interms[t - 1] = try_or_fail!(self, self.pow(n1, n2));
                 self.p += 1;
             },
+            &ArithmeticInstruction::Pow(ref a1, ref a2, t) => {
+                let n1 = try_or_fail!(self, self.get_number(a1));
+                let n2 = try_or_fail!(self, self.get_number(a2));
+
+                self.interms[t - 1] = try_or_fail!(self, self.pow(n1, n2));
+                self.p += 1;
+            },            
             &ArithmeticInstruction::RDiv(ref a1, ref a2, t) => {
                 let stub = MachineError::functor_stub(clause_name!("(rdiv)"), 2);
 
diff --git a/src/prolog/machine/system_calls.rs b/src/prolog/machine/system_calls.rs
index 2f295504..7821de66 100644
--- a/src/prolog/machine/system_calls.rs
+++ b/src/prolog/machine/system_calls.rs
@@ -3,7 +3,6 @@ use prolog_parser::parser::{get_desc, get_clause_spec};
 use prolog_parser::tabled_rc::*;
 
 use prolog::clause_types::*;
-use prolog::heap_iter::*;
 use prolog::heap_print::*;
 use prolog::machine::copier::*;
 use prolog::machine::machine_errors::*;
@@ -1112,7 +1111,7 @@ impl MachineState {
                 let mut vars = Vec::new();
 
                 {
-                    let iter = HCPreOrderIterator::new(self, a1);
+                    let iter = self.acyclic_pre_order_iter(a1);
 
                     for item in iter {
                         match item {
diff --git a/src/prolog/write.rs b/src/prolog/write.rs
index 51e65827..f413e1e3 100644
--- a/src/prolog/write.rs
+++ b/src/prolog/write.rs
@@ -298,7 +298,9 @@ impl fmt::Display for ArithmeticInstruction {
             &ArithmeticInstruction::Mul(ref a1, ref a2, ref t) =>
                 write!(f, "mul {}, {}, @{}", a1, a2, t),
             &ArithmeticInstruction::Pow(ref a1, ref a2, ref t) =>
-                write!(f, "pow {}, {}, @{}", a1, a2, t),
+                write!(f, "** {}, {}, @{}", a1, a2, t),
+            &ArithmeticInstruction::IntPow(ref a1, ref a2, ref t) =>
+                write!(f, "^ {}, {}, @{}", a1, a2, t),            
             &ArithmeticInstruction::Div(ref a1, ref a2, ref t) =>
                 write!(f, "div {}, {}, @{}", a1, a2, t),
             &ArithmeticInstruction::IDiv(ref a1, ref a2, ref t) =>
-- 
2.54.0