wip: proc: simplify expose macro

proc/Cargo.toml

@@ -8,6 +8,7 @@ edition     = { workspace = true }
 proc-macro = true
 
 [dependencies]
-syn = { version = "2", features = ["full", "extra-traits"] }
-quote = { version = "1" }
+syn         = { version = "2", features = ["full", "extra-traits"] }
+quote       = { version = "1" }
 proc-macro2 = { version = "1", features = ["span-locations"] }
+heck        = { version = "0.5" }

proc/src/lib.rs

@@ -22,10 +22,27 @@ mod proc_expose;
 
 #[proc_macro_attribute]
 pub fn view (meta: TokenStream, item: TokenStream) -> TokenStream {
-    self::proc_view::view_impl(meta.into(), item.into()).into()
+    use self::proc_view::{ViewDefinition, ViewMeta, ViewImpl};
+    write_macro(ViewDefinition(
+        parse_macro_input!(meta as ViewMeta),
+        parse_macro_input!(data as ViewImpl),
+    ))
 }
 
 #[proc_macro_attribute]
 pub fn expose (meta: TokenStream, item: TokenStream) -> TokenStream {
-    self::proc_expose::expose_impl(meta.into(), item.into()).into()
+    use self::proc_view::{ExposeDefinition, ExposeMeta, ExposeImpl};
+    write_macro(ExposeDefinition(
+        parse_macro_input!(meta as ExposeMeta),
+        parse_macro_input!(data as ExposeImpl),
+    ))
+}
+
+fn write_macro <T: ToTokens> (t: T) -> TokenStream {
+    let mut out = TokenStream2::new();
+    self::proc_expose::ExposeDefinition(
+        parse_macro_input!(meta as ExposeMeta),
+        parse_macro_input!(data as ExposeImpl),
+    ).to_tokens(&mut out);
+    out.into()
 }

proc/src/proc_expose.rs

@@ -1,27 +1,59 @@
 use crate::*;
 use syn::parse::discouraged::Speculative;
 
-pub(crate) fn expose_impl (meta: TokenStream, data: TokenStream) -> TokenStream {
-    let mut out = TokenStream2::new();
-    ExposeDefinition {
-        meta: parse_macro_input!(meta as ExposeMeta),
-        data: parse_macro_input!(data as ExposeImpl),
-    }.to_tokens(&mut out);
-    out.into()
+#[derive(Debug, Clone)]
+pub(crate) struct ExposeDefinition(pub(crate) ExposeMeta, pub(crate) ExposeImpl);
+
+#[derive(Debug, Clone)]
+pub(crate) struct ExposeMeta;
+
+#[derive(Debug, Clone)]
+pub(crate) struct ExposeImpl {
+    block: ItemImpl,
+    exposed: BTreeMap<ExposeType, BTreeMap<ExposeSym, ExposeArm>>,
 }
 
 #[derive(Debug, Clone)]
-struct ExposeDefinition {
-    meta: ExposeMeta,
-    data: ExposeImpl,
+struct ExposeArm {
+    key: ExposeSym,
+    value: Expr
 }
 
-impl Parse for ExposeDefinition {
+#[derive(Debug, Clone)]
+struct ExposeSym(LitStr);
+
+#[derive(Debug, Clone)]
+struct ExposeType(Box<Type>);
+
+impl Parse for ExposeMeta {
     fn parse (input: ParseStream) -> Result<Self> {
-        Ok(Self {
-            meta: input.parse::<ExposeMeta>()?,
-            data: input.parse::<ExposeImpl>()?,
-        })
+        Ok(Self)
+    }
+}
+
+impl Parse for ExposeImpl {
+    fn parse (input: ParseStream) -> Result<Self> {
+        let block = input.parse::<ItemImpl>()?;
+        let mut exposed: BTreeMap<ExposeType, BTreeMap<ExposeSym, ExposeArm>> = Default::default();
+        for item in block.items.iter() {
+            if let ImplItem::Fn(ImplItemFn { sig: Signature { ident, output, .. }, .. }) = item {
+                if let ReturnType::Type(_, return_type) = output {
+                    let return_type = ExposeType(return_type.clone());
+                    if !exposed.contains_key(return_type) {
+                        exposed.insert(return_type.clone(), Default::default())
+                    }
+                    let values = exposed.get_mut(&return_type).unwrap();
+                    let key = format!(":{}", AsKebabCase(&ident));
+                    if values.contains_key(key) {
+                        return Err(input.error(format!("already defined: {key}")))
+                    }
+                    values.insert(key, ident.clone());
+                } else {
+                    return Err(input.error("output type must be specified"))
+                }
+            }
+        }
+        Ok(Self { block, exposed })
     }
 }
 
@@ -34,62 +66,6 @@ impl ToTokens for ExposeDefinition {
     }
 }
 
-#[derive(Debug, Clone)]
-struct ExposeMeta {}
-
-impl Parse for ExposeMeta {
-    fn parse (input: ParseStream) -> Result<Self> {
-        Ok(Self {})
-    }
-}
-
-#[derive(Debug, Clone)]
-struct ExposeImpl {
-    target: Ident,
-    items:  Vec<ImplItem>,
-    types:  BTreeMap<ExposeType, BTreeMap<ExposeSym, ExposeArm>>,
-}
-
-impl Parse for ExposeImpl {
-    fn parse (input: ParseStream) -> Result<Self> {
-        let _impl = input.parse::<Token![impl]>()?;
-        let target = input.parse::<Ident>()?;
-        let group;
-        let brace = braced!(group in input);
-        let mut items = vec![];
-        let mut types: BTreeMap<ExposeType, BTreeMap<ExposeSym, ExposeArm>> = Default::default();
-        while !group.is_empty() {
-            let fork = group.fork();
-            if let Ok(block) = fork.parse::<ExposeBlock>() {
-                let t = block.type_.into();
-                if let Some(values) = types.get_mut(&t) {
-                    for (key, value) in block.values.into_iter() {
-                        if values.contains_key(&key) {
-                            return Err(input.error(format!("{key:?} ({t:?}): already exists")))
-                        } else {
-                            values.insert(key, value);
-                        }
-                    }
-                } else {
-                    types.insert(t, block.values);
-                }
-                group.advance_to(&fork);
-                continue
-            }
-            let fork = group.fork();
-            if let Ok(item) = fork.parse::<ImplItem>() {
-                items.push(item);
-                group.advance_to(&fork);
-                continue
-            }
-            return Err(input.error(
-                "expected either item or #[tengri::expose(type)] { \":key\" => value }"
-            ));
-        }
-        Ok(Self { target, items, types })
-    }
-}
-
 impl ToTokens for ExposeImpl {
     fn to_tokens (&self, out: &mut TokenStream2) {
         let Self { target, items, types } = self;
@@ -97,7 +73,7 @@ impl ToTokens for ExposeImpl {
             out.append(token);
         }
         for (t, variants) in types.iter() {
-            let predef = match format!("{}", quote! { #t }).as_str() {
+            let predefined = match format!("{}", quote! { #t }).as_str() {
                 "bool" => vec![
                     quote! { ::tengri::dsl::Value::Sym(":true")  => true  },
                     quote! { ::tengri::dsl::Value::Sym(":false") => false },
@@ -113,7 +89,7 @@ impl ToTokens for ExposeImpl {
                 impl ::tengri::dsl::Context<#t> for #target {
                     fn get (&self, dsl: &::tengri::dsl::Value) -> Option<#t> {
                         Some(match dsl {
-                            #(#predef,)*
+                            #(#predefined,)*
                             #(#values,)*
                             _ => return None
                         })
@@ -127,58 +103,6 @@ impl ToTokens for ExposeImpl {
     }
 }
 
-#[derive(Debug, Clone)]
-struct ExposeBlock {
-    type_:  Type,
-    values: BTreeMap<ExposeSym, ExposeArm>,
-}
-
-impl Parse for ExposeBlock {
-    fn parse (input: ParseStream) -> Result<Self> {
-        let _ = input.parse::<Token![#]>()?;
-
-        let group;
-        let bracket = bracketed!(group in input);
-        let path = group.parse::<Path>()?;
-        let type_ = if
-            path.segments.get(0).map(|x|x.ident.to_string()) == Some("tengri".to_string()) &&
-            path.segments.get(1).map(|x|x.ident.to_string()) == Some("expose".to_string()) 
-        {
-            let token;
-            let paren = parenthesized!(token in group);
-            token.parse::<Type>()?
-        } else {
-            return Err(input.error("expected #[tengri::expose(type)]"))
-        };
-
-        let group;
-        let brace = braced!(group in input);
-        let mut values = BTreeMap::new();
-        while !group.is_empty() {
-            let arm = group.parse::<ExposeArm>()?;
-            values.insert(arm.key.clone(), arm);
-            let _ = group.parse::<Token![,]>()?;
-        }
-        Ok(Self { type_, values })
-    }
-}
-
-#[derive(Debug, Clone)]
-struct ExposeArm {
-    key:   ExposeSym,
-    value: Expr
-}
-
-impl Parse for ExposeArm {
-    fn parse (input: ParseStream) -> Result<Self> {
-        let key = input.parse::<LitStr>()?.into();
-        let _ = input.parse::<Token![=]>()?;
-        let _ = input.parse::<Token![>]>()?;
-        let value = input.parse::<Expr>()?;
-        Ok(Self { key, value })
-    }
-}
-
 impl ToTokens for ExposeArm {
     fn to_tokens (&self, out: &mut TokenStream2) {
         let Self { key, value } = self;
@@ -207,9 +131,6 @@ impl ToTokens for ExposeArm {
     }
 }
 
-#[derive(Debug, Clone)]
-struct ExposeSym(LitStr);
-
 impl From<LitStr> for ExposeSym {
     fn from (this: LitStr) -> Self {
         Self(this)
@@ -242,9 +163,6 @@ impl PartialEq for ExposeSym {
 
 impl Eq for ExposeSym {}
 
-#[derive(Debug, Clone)]
-struct ExposeType(Type);
-
 impl From<Type> for ExposeType {
     fn from (this: Type) -> Self {
         Self(this)
@@ -284,109 +202,107 @@ impl ToTokens for ExposeType {
 }
 
 #[cfg(test)] #[test] fn test_expose_definition () {
-    let parsed: ExposeImpl = pq! {
-        //#[tengri_proc::expose]
-        impl Something {
-            #[tengri::expose(bool)] {
-                ":bool1" => true || false,
-            }
-            fn something () {}
-        }
-    };
-    // FIXME:
-    //assert_eq!(
-        //format!("{}", quote! { #parsed }),
-        //format!("{}", quote! {
-            //impl Something {
-                //fn something () {}
-            //}
-            //impl ::tengri::Context<bool> for Something {
-                //fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
-                    //Some(match dsl {
-                        //::tengri::Value::Sym(":true")  => true,
-                        //::tengri::Value::Sym(":false") => false,
-                        //::tengri::Value::Sym(":bool1") => true || false,
-                        //_ => return None
-                    //})
-                //}
-            //}
-        //})
-    //);
+    // TODO
+    //let parsed: ExposeImpl = pq! {
+        ////#[tengri_proc::expose]
+        //impl Something {
+            //fn something () -> bool {}
+        //}
+    //};
+    //// FIXME:
+    ////assert_eq!(
+        ////format!("{}", quote! { #parsed }),
+        ////format!("{}", quote! {
+            ////impl Something {
+                ////fn something () {}
+            ////}
+            ////impl ::tengri::Context<bool> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":true")  => true,
+                        ////::tengri::Value::Sym(":false") => false,
+                        ////::tengri::Value::Sym(":bool1") => true || false,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+        ////})
+    ////);
 
-    let parsed: ExposeImpl = pq! {
-        //#[tengri_proc::expose]
-        impl Something {
-            #[tengri::expose(bool)] {
-                ":bool1" => true || false,
-            }
-            #[tengri::expose(u16)] {
-                ":u161" => 0 + 1,
-            }
-            #[tengri::expose(usize)] {
-                ":usize1" => 1 + 2,
-            }
-            #[tengri::expose(Arc<str>)] {
-                ":arcstr1" => "foo".into(),
-            }
-            #[tengri::expose(Option<Arc<str>>)] {
-                ":optarcstr1" => Some("bar".into()),
-                ":optarcstr2" => Some("baz".into()),
-            }
-            fn something () {}
-        }
-    };
-    // FIXME:
-    //assert_eq!(
-        //format!("{}", quote! { #parsed }),
-        //format!("{}", quote! {
-            //impl Something {
-                //fn something () {}
+    //let parsed: ExposeImpl = pq! {
+        ////#[tengri_proc::expose]
+        //impl Something {
+            //#[tengri::expose(bool)] {
+                //":bool1" => true || false,
             //}
-            //impl ::tengri::Context<Arc<str>> for Something {
-                //fn get (&self, dsl: &::tengri::Value) -> Option<Arc<str>> {
-                    //Some(match dsl {
-                        //::tengri::Value::Sym(":arcstr1") => "foo".into(),
-                        //_ => return None
-                    //})
-                //}
+            //#[tengri::expose(u16)] {
+                //":u161" => 0 + 1,
             //}
-            //impl ::tengri::Context<Option<Arc<str>>> for Something {
-                //fn get (&self, dsl: &::tengri::Value) -> Option<Option<Arc<str>>> {
-                    //Some(match dsl {
-                        //::tengri::Value::Sym(":optarcstr1") => Some("bar".into()),
-                        //::tengri::Value::Sym(":optarcstr2") => Some("baz".into()),
-                        //_ => return None
-                    //})
-                //}
+            //#[tengri::expose(usize)] {
+                //":usize1" => 1 + 2,
             //}
-            //impl ::tengri::Context<bool> for Something {
-                //fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
-                    //Some(match dsl {
-                        //::tengri::Value::Sym(":true")  => true,
-                        //::tengri::Value::Sym(":false") => false,
-                        //::tengri::Value::Sym(":bool1") => true || false,
-                        //_ => return None
-                    //})
-                //}
+            //#[tengri::expose(Arc<str>)] {
+                //":arcstr1" => "foo".into(),
             //}
-            //impl ::tengri::Context<u16> for Something {
-                //fn get (&self, dsl: &::tengri::Value) -> Option<u16> {
-                    //Some(match dsl {
-                        //::tengri::Value::Num(n) => *n as u16,
-                        //::tengri::Value::Sym(":u161") => 0 + 1,
-                        //_ => return None
-                    //})
-                //}
+            //#[tengri::expose(Option<Arc<str>>)] {
+                //":optarcstr1" => Some("bar".into()),
+                //":optarcstr2" => Some("baz".into()),
             //}
-            //impl ::tengri::Context<usize> for Something {
-                //fn get (&self, dsl: &::tengri::Value) -> Option<usize> {
-                    //Some(match dsl {
-                        //::tengri::Value::Num(n) => *n as usize,
-                        //::tengri::Value::Sym(":usize1") => 1 + 2,
-                        //_ => return None
-                    //})
-                //}
-            //}
-        //})
-    //)
+            //fn something () {}
+        //}
+    //};
+    //// FIXME:
+    ////assert_eq!(
+        ////format!("{}", quote! { #parsed }),
+        ////format!("{}", quote! {
+            ////impl Something {
+                ////fn something () {}
+            ////}
+            ////impl ::tengri::Context<Arc<str>> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<Arc<str>> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":arcstr1") => "foo".into(),
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<Option<Arc<str>>> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<Option<Arc<str>>> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":optarcstr1") => Some("bar".into()),
+                        ////::tengri::Value::Sym(":optarcstr2") => Some("baz".into()),
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<bool> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<bool> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Sym(":true")  => true,
+                        ////::tengri::Value::Sym(":false") => false,
+                        ////::tengri::Value::Sym(":bool1") => true || false,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<u16> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<u16> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Num(n) => *n as u16,
+                        ////::tengri::Value::Sym(":u161") => 0 + 1,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+            ////impl ::tengri::Context<usize> for Something {
+                ////fn get (&self, dsl: &::tengri::Value) -> Option<usize> {
+                    ////Some(match dsl {
+                        ////::tengri::Value::Num(n) => *n as usize,
+                        ////::tengri::Value::Sym(":usize1") => 1 + 2,
+                        ////_ => return None
+                    ////})
+                ////}
+            ////}
+        ////})
+    ////)
 }

proc/src/proc_view.rs

@@ -1,27 +1,15 @@
 use crate::*;
 
-pub(crate) fn view_impl (meta: TokenStream, data: TokenStream) -> TokenStream {
-    let mut out = TokenStream2::new();
-    ViewDefinition {
-        meta: parse_macro_input!(meta as ViewMeta),
-        data: parse_macro_input!(data as ViewImpl),
-    }.to_tokens(&mut out);
-    out.into()
-}
+#[derive(Debug, Clone)]
+pub(crate) struct ViewDefinition(pub(crate) ViewMeta, pub(crate) ViewImpl);
 
 #[derive(Debug, Clone)]
-struct ViewDefinition {
-    meta: ViewMeta,
-    data: ViewImpl,
-}
-
-#[derive(Debug, Clone)]
-struct ViewMeta {
+pub(crate) struct ViewMeta {
     output: Ident,
 }
 
 #[derive(Debug, Clone)]
-struct ViewImpl {
+pub(crate) struct ViewImpl {
     target: Ident,
     items:  Vec<ViewItem>,
     syms:   Vec<ViewSym>,
@@ -39,15 +27,6 @@ struct ViewSym {
     name:   Ident,
 }
 
-impl Parse for ViewDefinition {
-    fn parse (input: ParseStream) -> Result<Self> {
-        Ok(Self {
-            meta: input.parse::<ViewMeta>()?,
-            data: input.parse::<ViewImpl>()?,
-        })
-    }
-}
-
 impl Parse for ViewMeta {
     fn parse (input: ParseStream) -> Result<Self> {
         Ok(Self {
@@ -163,10 +142,7 @@ impl ToTokens for ViewItem {
 
 impl ToTokens for ViewDefinition {
     fn to_tokens (&self, out: &mut TokenStream2) {
-        let Self {
-            meta: ViewMeta { output },
-            data: ViewImpl { target, syms, items },
-        } = self;
+        let Self(ViewMeta { output }, ViewImpl { target, syms, items }) = self;
         for token in quote! {
             /// Augmented by [tengri_proc].
             impl #target {