Store short index in variable access.

src/ast.rs

@@ -9,7 +9,7 @@ use crate::stdlib::{
     fmt,
     hash::Hash,
     iter::empty,
-    num::NonZeroUsize,
+    num::{NonZeroU8, NonZeroUsize},
     ops::{Add, AddAssign},
     string::String,
     vec,
@@ -1574,8 +1574,15 @@ pub enum Expr {
     ),
     /// ()
     Unit(Position),
-    /// Variable access - (optional index, optional (hash, modules), variable name)
-    Variable(Box<(Option<NonZeroUsize>, Option<(u64, NamespaceRef)>, Ident)>),
+    /// Variable access - optional short index, (optional index, optional (hash, modules), variable name)
+    ///
+    /// The short index is [`u8`] which is used when the index is <= 255, which should be the vast
+    /// majority of cases (unless there are more than 255 variables defined!).
+    /// This is to avoid reading a pointer redirection during each variable access.
+    Variable(
+        Option<NonZeroU8>,
+        Box<(Option<NonZeroUsize>, Option<(u64, NamespaceRef)>, Ident)>,
+    ),
     /// Property access - ((getter, hash), (setter, hash), prop)
     Property(Box<((Identifier, u64), (Identifier, u64), Ident)>),
     /// { [statement][Stmt] ... }
@@ -1644,7 +1651,7 @@ impl Expr {
     #[inline(always)]
     pub(crate) fn get_variable_access(&self, non_qualified: bool) -> Option<&str> {
         match self {
-            Self::Variable(x) if !non_qualified || x.1.is_none() => Some((x.2).name.as_str()),
+            Self::Variable(_, x) if !non_qualified || x.1.is_none() => Some((x.2).name.as_str()),
             _ => None,
         }
     }
@@ -1666,7 +1673,7 @@ impl Expr {
             Self::Map(_, pos) => *pos,
             Self::Property(x) => (x.2).pos,
             Self::Stmt(x) => x.pos,
-            Self::Variable(x) => (x.2).pos,
+            Self::Variable(_, x) => (x.2).pos,
             Self::FnCall(_, pos) => *pos,
 
             Self::And(x, _) | Self::Or(x, _) => x.lhs.position(),
@@ -1696,7 +1703,7 @@ impl Expr {
             Self::FnPointer(_, pos) => *pos = new_pos,
             Self::Array(_, pos) => *pos = new_pos,
             Self::Map(_, pos) => *pos = new_pos,
-            Self::Variable(x) => (x.2).pos = new_pos,
+            Self::Variable(_, x) => (x.2).pos = new_pos,
             Self::Property(x) => (x.2).pos = new_pos,
             Self::Stmt(x) => x.pos = new_pos,
             Self::FnCall(_, pos) => *pos = new_pos,
@@ -1724,7 +1731,7 @@ impl Expr {
 
             Self::Stmt(x) => x.statements.iter().all(Stmt::is_pure),
 
-            Self::Variable(_) => true,
+            Self::Variable(_, _) => true,
 
             _ => self.is_constant(),
         }
@@ -1794,7 +1801,7 @@ impl Expr {
                 _ => false,
             },
 
-            Self::Variable(_) => match token {
+            Self::Variable(_, _) => match token {
                 #[cfg(not(feature = "no_index"))]
                 Token::LeftBracket => true,
                 Token::LeftParen => true,