wip: scaffold proc crate and view macro

proc/src/proc_view.rs

@@ -0,0 +1,80 @@
+use proc_macro::TokenStream;
+use proc_macro2::{TokenStream as TokenStream2};
+
+pub(crate) fn view_impl (meta: TokenStream, item: TokenStream) -> TokenStream {
+    let ViewMeta { output, define, attrs } = syn::parse_macro_input!(meta as ViewMeta);
+    let ViewItem { target, mapped, items } = syn::parse_macro_input!(item as ViewItem);
+    quote::quote! {
+        #attrs
+        impl #target {
+            #items
+        }
+        impl ::tengri::Content<#output> for #target {
+            fn content (&self) -> impl Render<#output> {
+                self.size.of(::tengri::View(self, #define))
+            }
+        }
+        impl<'a> ::tengri::ViewContext<'a, #output> for #target {
+            fn get_content_sym (&'a self, value: &Value<'a>) -> Option<RenderBox<'a, #output>> {
+                match value {
+                    #mapped
+                    _ => panic!("expected Sym(content), got: {value:?}")
+                }
+                //if let Value::Sym(s) = value {
+                    //match *s {
+                        //$($sym => Some($body.boxed()),)*
+                        //_ => None
+                    //}
+                //} else {
+                    //panic!("expected Sym(content), got: {value:?}")
+                //}
+            }
+        }
+    }.into()
+}
+
+struct ViewMeta {
+    attrs:  &'static str,
+    output: &'static str,
+    define: &'static str,
+}
+
+impl syn::parse::Parse for ViewMeta {
+    fn parse (input: syn::parse::ParseStream) -> syn::parse::Result<Self> {
+        Ok(Self {
+            attrs:  "",
+            output: "",
+            define: "",
+        })
+    }
+}
+
+struct ViewItem {
+    items:  &'static str,
+    target: &'static str,
+    mapped: &'static str,
+}
+
+impl syn::parse::Parse for ViewItem {
+    fn parse (input: syn::parse::ParseStream) -> syn::parse::Result<Self> {
+        Ok(Self {
+            items:  "",
+            target: "",
+            mapped: "",
+        })
+    }
+}
+
+#[cfg(test)] #[test] fn test_view () {
+
+    let _: syn::ItemImpl = syn::parse_quote! {
+        #[tengri::view(Tui)]
+        impl SomeView {
+            #[tengri::view(":view")]
+            fn view (&self) -> impl Content<TuiOut> + use<'_> {
+                "view"
+            }
+        }
+    };
+
+}