Add custom syntax.

src/optimize.rs

@@ -2,7 +2,7 @@ use crate::any::Dynamic;
 use crate::calc_fn_hash;
 use crate::engine::{Engine, Imports, KEYWORD_DEBUG, KEYWORD_EVAL, KEYWORD_PRINT, KEYWORD_TYPE_OF};
 use crate::module::Module;
-use crate::parser::{map_dynamic_to_expr, Expr, ReturnType, ScriptFnDef, Stmt, AST};
+use crate::parser::{map_dynamic_to_expr, CustomExpr, Expr, ReturnType, ScriptFnDef, Stmt, AST};
 use crate::scope::{Entry as ScopeEntry, EntryType as ScopeEntryType, Scope};
 use crate::utils::StaticVec;
 
@@ -598,6 +598,14 @@ fn optimize_expr(expr: Expr, state: &mut State) -> Expr {
             state.find_constant(&name).expect("should find constant in scope!").clone().set_position(pos)
         }
 
+        // Custom syntax
+        Expr::Custom(x) => Expr::Custom(Box::new((
+            CustomExpr(
+                (x.0).0.into_iter().map(|expr| optimize_expr(expr, state)).collect(),
+                (x.0).1),
+            x.1
+        ))),
+
         // All other expressions - skip
         expr => expr,
     }