refactor: simplify yes/no logic, fix README.md doctest

README.md

@@ -18,25 +18,25 @@ let v: &Value = todo!();
 matchbox::matchbox!{
     match v {
         Nil => todo!(),
-        Cons(Deref @ Symbol(Deref @ "quote"), Deref @ Cons(x, Deref @ Nil)) => todo!(),
+        Cons(deref!(Symbol(deref!("quote"))), deref!(Cons(x, deref! @ Nil))) => todo!(),
         _ => todo!(),
     }
 }
 ```
 
-But there is a problem in my crate: all arms with `Deref @` are ignored when compiler performs exhaustiveness checking. So sometimes you will need to add `_ => unreachable!()` to the end.
+But there is a problem in my crate: all arms with `deref! @` are ignored when compiler performs exhaustiveness checking. So sometimes you will need to add `_ => unreachable!()` to the end.
 
 I.e. it is possible that your arms are exhaustive, but the compiler will not be able to check this. But it is not possible that you arms are not exhaustive and the compiler will falsely report them as exhaustive.
 
 (I decided not to implement full exhaustiveness checking, because I hope that truly native support for deref patterns will be implemented in the rustc soon, so my work will be unneeded anyway. But if you want to implement similar macro with full exhaustiveness checking, go ahead, I can even link to your project here.)
 
-The macro calls `Deref::deref` internally. Keep in mind that `Deref::deref` takes REFERENCE to smart pointer and returns REFERENCE to pointee. So this code will work: `match &Nil { Deref @ x => ... }`, but this will not: `match Nil { Deref @ x => ... }`.
+The macro calls `Deref::deref` internally. Keep in mind that `Deref::deref` takes REFERENCE to smart pointer and returns REFERENCE to pointee. So this code will work: `match &Nil { deref! @ x => ... }`, but this will not: `match Nil { deref! @ x => ... }`.
 
 Consider this code:
 ```rust,ignore
 matchbox::matchbox!{
     match v {
-        Symbol(Deref @ x) => {
+        Symbol(deref! @ x) => {
             // some_code_here
         }
         _ => {

src/lib.rs

@@ -155,15 +155,15 @@ fn matchbox_impl(mut m: syn::ExprMatch) -> syn::ExprMatch {
         arm.pat = my_fold.fold_pat(arm.pat);
 
         if !my_fold.binds.is_empty() {
-            let (yes, no) = if let Some((_if_token, src_guard)) = arm.guard {
-                (*src_guard, syn::parse_quote_spanned! {span=> false })
-            } else {
-                (
-                    syn::parse_quote_spanned! {span=> true },
-                    syn::parse_quote_spanned! {span=> false },
-                )
+            let t = {
+                let yes = if let Some((_if_token, src_guard)) = arm.guard {
+                    *src_guard
+                } else {
+                    syn::parse_quote_spanned! {span=> true }
+                };
+                let no = syn::parse_quote_spanned! {span=> false };
+                tower(&my_fold.binds, yes, &no, true)
             };
-            let t = tower(&my_fold.binds, yes, &no, true);
             arm.guard = Some((
                 syn::Token![if](span),
                 Box::new(syn::parse_quote_spanned! {span=> { #[allow(unused_variables)] #t } }),