1 files changed, 89 insertions, 0 deletions
diff --git a/macros/src/util/tokens.rs b/macros/src/util/tokens.rs
new file mode 100644
index 0000000..c614ea0
--- /dev/null
+++ b/macros/src/util/tokens.rs
@@ -0,0 +1,89 @@
+use std::fmt::Write;
+
+use proc_macro2::{Delimiter, Spacing, TokenTree};
+use quote::ToTokens;
+
+pub trait ToTokensExt
+{
+    fn to_str_pretty(&self) -> String;
+}
+
+impl<T: ToTokens> ToTokensExt for T
+{
+    fn to_str_pretty(&self) -> String
+    {
+        let mut spaceable = Spaceable::None;
+
+        self.to_token_stream()
+            .into_iter()
+            .fold(String::new(), |mut acc, token_tree| {
+                let prev_spaceable = spaceable;
+
+                spaceable = get_tt_spaceable(&token_tree);
+
+                if matches!(prev_spaceable, Spaceable::Left | Spaceable::LeftRight)
+                    && matches!(spaceable, Spaceable::Right | Spaceable::LeftRight)
+                {
+                    write!(acc, " ").ok();
+                }
+
+                match token_tree {
+                    TokenTree::Group(group) => match group.delimiter() {
+                        Delimiter::Parenthesis => {
+                            write!(acc, "({})", group.stream().to_str_pretty()).ok();
+                        }
+                        Delimiter::Brace => {
+                            write!(acc, "{{{}}}", group.stream().to_str_pretty()).ok();
+                        }
+                        Delimiter::Bracket => {
+                            write!(acc, "[{}]", group.stream().to_str_pretty()).ok();
+                        }
+                        Delimiter::None => {
+                            write!(acc, "{}", group.stream().to_str_pretty()).ok();
+                        }
+                    },
+                    tt => {
+                        write!(acc, "{tt}").ok();
+                    }
+                }
+
+                acc
+            })
+    }
+}
+
+fn get_tt_spaceable(token_tree: &TokenTree) -> Spaceable
+{
+    match &token_tree {
+        TokenTree::Ident(_) => Spaceable::LeftRight,
+        TokenTree::Punct(punct)
+            if punct.spacing() == Spacing::Alone && (punct.as_char() == '+') =>
+        {
+            Spaceable::LeftRight
+        }
+        TokenTree::Punct(punct)
+            if punct.spacing() == Spacing::Alone
+                && (punct.as_char() == '>' || punct.as_char() == ',') =>
+        {
+            Spaceable::Left
+        }
+        TokenTree::Punct(punct)
+            if punct.spacing() == Spacing::Joint && punct.as_char() == '-' =>
+        {
+            // Is part of ->
+            Spaceable::Right
+        }
+        TokenTree::Punct(punct) if punct.as_char() == '&' => Spaceable::Right,
+        TokenTree::Group(_) => Spaceable::Left,
+        _ => Spaceable::None,
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+enum Spaceable
+{
+    Left,
+    Right,
+    LeftRight,
+    None,
+}