Make PostScriptOp copyable again

src/functions.rs

@@ -238,7 +238,7 @@ deref!('a, PostScriptFunction<'a> => Stream<'a>, stream);
 
 /// PostScript operators for use in Type 4 functions.
 #[derive(Debug, Clone, PartialEq)]
-pub enum PostScriptOp {
+pub enum PostScriptOp<'a> {
     /// Push a real number.
     Real(f32),
     /// Push an integer number.
@@ -315,9 +315,9 @@ pub enum PostScriptOp {
     Xor,
 
     /// Conditional. Runs if boolean argument is true.
-    If(Vec<Self>),
+    If(&'a [Self]),
     /// Conditional. Decides which branch to run depending on boolean argument.
-    IfElse(Vec<Self>, Vec<Self>),
+    IfElse(&'a [Self], &'a [Self]),
 
     /// Copy the top elements. One integer argument.
     Copy,
@@ -333,7 +333,7 @@ pub enum PostScriptOp {
     Roll,
 }
 
-impl PostScriptOp {
+impl PostScriptOp<'_> {
     /// Encode a slice of operations into a byte stream.
     pub fn encode(ops: &[Self]) -> Vec<u8> {
         let mut buf = Vec::new();
@@ -441,13 +441,13 @@ mod tests {
             Dup,
             Real(0.0),
             Ge,
-            IfElse(vec![Real(1.0), Add], vec![Neg]),
+            IfElse(&[Real(1.0), Add], &[Neg]),
             Add,
         ];
 
         assert_eq!(
             PostScriptOp::encode(&ops),
-            b"{\n3.0\n2.0\nmul\nexch\ndup\n0.0\nge\n{\n1.0\nadd\n}\n{neg}\nifelse\nadd\n}"
+            b"{ 3.0 2.0 mul exch dup 0.0 ge { 1.0 add } {neg} ifelse add }"
         );
     }
 }