Ensure the optimisation happens even at the end of the file.

If `[-]` was the last sequence in the program, the bounds check was too strict, and would prevent it being optimised. The resulting program still ran correctly, but unnecessarily slow. This commit fixes that.
ltratt · Oct 28, 2023 · c28988e · c28988e
1 parent 3a35f8a
commit c28988e
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/interp7/src/main.rs b/interp7/src/main.rs
@@ -42,7 +42,7 @@ fn main() -> Result<(), Box<dyn error::Error>> {
   }
   let mut i = 0;
   while i < prog.len() {
-    if i + 3 < prog.len() && matches!(prog[i..i+3], [Ops::LBrack(_), Ops::Sub(1), Ops::RBrack(_)]) {
+    if i + 2 < prog.len() && matches!(prog[i..i+3], [Ops::LBrack(_), Ops::Sub(1), Ops::RBrack(_)]) {
       prog.splice(i..i+3, [Ops::Zero]);
       i += 3;
     } else { i += 1; }

diff --git a/interp8/src/main.rs b/interp8/src/main.rs
@@ -11,7 +11,7 @@ fn main() -> Result<(), Box<dyn error::Error>> {
 fn optimise(prog: &mut Vec<Ops>) {
   let mut i = 0;
   while i < prog.len() {
-    if i + 3 < prog.len() && matches!(prog[i..i+3], [Ops::LBrack(_), Ops::Sub(1), Ops::RBrack(_)]) {
+    if i + 2 < prog.len() && matches!(prog[i..i+3], [Ops::LBrack(_), Ops::Sub(1), Ops::RBrack(_)]) {
       prog.splice(i..i+3, [Ops::Zero]);
       i += 3;
     } else { i += 1; }