Rename the <tal> operator to <sum>

This is a more memorable name, and can be implemented for lists in the
future as well.

2 files changed, 7 insertions, 6 deletions

diff --git a/src/types/expression_stack.rs b/src/types/expression_stack.rs
index 228fa2d..62a44fb 100644
--- a/src/types/expression_stack.rs
+++ b/src/types/expression_stack.rs
@@ -62,7 +62,7 @@ impl ExpressionStack {
             Operator::BitXor           => { pop!(b); pop!(a); push!(a ^ b) },
             Operator::BitNot           => {          pop!(a); push!(!a) },
             Operator::Length           => {          pop!(a); push!(width(a) as isize) },
-            Operator::Tally            => {          pop!(a); push!(tally(a) as isize) },
+            Operator::Sum              => {          pop!(a); push!(ones(a) as isize) },
             Operator::Absolute         => {          pop!(a); push!(a.wrapping_abs()) },
         }
         return Ok(());
@@ -78,7 +78,8 @@ pub fn width(value: isize) -> u32 {
     }
 }
 
-pub fn tally(value: isize) -> u32 {
+/// Count the number of one bits in a value.
+pub fn ones(value: isize) -> u32 {
     let width = width(value);
     let mask = 2i32.pow(width) -1;
     let value = (value as usize) & (mask as usize);
diff --git a/src/types/operator.rs b/src/types/operator.rs
index da4dfb4..e360567 100644
--- a/src/types/operator.rs
+++ b/src/types/operator.rs
@@ -19,7 +19,7 @@ pub enum Operator {
     BitXor,
     BitNot,
     Length,
-    Tally,
+    Sum,
     Absolute,
 }
 
@@ -59,9 +59,9 @@ impl Operator {
             "<xor>" => Some(Operator::BitXor),
             "<not>" => Some(Operator::BitNot),
             "<len>" => Some(Operator::Length),
-            "<tal>" => Some(Operator::Tally),
+            "<sum>" => Some(Operator::Sum),
             "<abs>" => Some(Operator::Absolute),
-            _      => None,
+            _       => None,
         }
     }
 }
@@ -88,7 +88,7 @@ impl std::fmt::Display for Operator {
             Operator::BitXor           => "<xor>",
             Operator::BitNot           => "<not>",
             Operator::Length           => "<len>",
-            Operator::Tally            => "<tal>",
+            Operator::Sum              => "<sum>",
             Operator::Absolute         => "<abs>",
         };
         write!(f, "{string}")