downgrade to cargo 2018 edition

Author: ZocoLini

modules/mexpreval/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "mexpreval"
 version = "0.1.0"
-edition = "2021"
+edition = "2018"
 
 [dependencies]
 meval = { version = "0.2.0" }

modules/mexpreval/src/lib.rs

@@ -43,12 +43,12 @@ pub unsafe extern "C" fn eval_f_exprs(
                 let expr = exprs_cache.entry(*ptr).or_insert_with(|| {
                     let c_str = CStr::from_ptr(*ptr);
                     let s = c_str.to_str().unwrap_unchecked();
-                    Expr::from_str(s).unwrap_or_else(|e| panic!("Error parsing expresion {s}: {e}"))
+                    Expr::from_str(s).unwrap_or_else(|e| panic!("Error parsing expresion {}: {}", s, e))
                 });
 
                 ydot[i] = expr
                     .eval_with_context(&*ctx)
-                    .unwrap_or_else(|e| panic!("Error evaluating epresion: {e}"));
+                    .unwrap_or_else(|e| panic!("Error evaluating epresion: {}", e));
             }
         });
     });