learn how workspaces + proc macros work & restructure everything

macro/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "iris-macro"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+quote = "1.0.42"
+syn = { version = "2.0.111", features = ["full"] }
+
+[lib]
+proc-macro = true

macro/src/lib.rs

@@ -0,0 +1,72 @@
+extern crate proc_macro;
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{
+    Block, Ident, Signature, Token, Visibility,
+    parse::{Parse, ParseStream, Result},
+    parse_macro_input,
+};
+
+struct Input {
+    vis: Visibility,
+    name: Ident,
+    fns: Vec<InputFn>,
+}
+
+struct InputFn {
+    sig: Signature,
+    body: Block,
+}
+
+impl Parse for Input {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let vis = input.parse()?;
+        let name = input.parse()?;
+        input.parse::<Token![;]>()?;
+        let mut fns = Vec::new();
+        while !input.is_empty() {
+            let sig = input.parse()?;
+            let body = input.parse()?;
+            fns.push(InputFn { sig, body })
+        }
+        if !input.is_empty() {
+            input.error("function expected");
+        }
+        Ok(Input { vis, name, fns })
+    }
+}
+
+// pub trait $name<W: WidgetLike<Tag>, Tag> {
+//     $(
+//     fn $fn $(<$($T $(: $TT $(+ $TL)?)?,)*>)?($self $(, $arg: $ty)*) -> $ret;
+//     )*
+// }
+//
+// impl<W: WidgetLike<Tag>, Tag> $name<W, Tag> for W {
+//     $(
+//     fn $fn $(<$($T $(: $TT $(+ $TL)?)?,)*>)?($self $(, $arg: $ty)*) -> $ret {
+//         $code
+//     }
+//     )*
+// }
+
+#[proc_macro]
+pub fn widget_trait(input: TokenStream) -> TokenStream {
+    let Input { vis, name, fns } = parse_macro_input!(input as Input);
+
+    let sigs: Vec<_> = fns.iter().map(|f| f.sig.clone()).collect();
+    let impls: Vec<_> = fns
+        .iter()
+        .map(|InputFn { sig, body }| quote! { #sig #body })
+        .collect();
+
+    TokenStream::from(quote! {
+        #vis trait #name<WL: WidgetLike<Tag>, Tag> {
+            #(#sigs;)*
+        }
+
+        impl<WL: WidgetLike<Tag>, Tag> #name<WL, Tag> for WL {
+            #(#impls)*
+        }
+    })
+}