proc: builtims

dsl/src/dsl_provide.rs

@@ -1,10 +1,17 @@
 use crate::*;
 
-// maybe their names should be switched around?
+///// Implement the [Give] trait, which boils down to
+///// specifying two types and providing an expression.
+#[macro_export] macro_rules! from_dsl {
+    ($Type:ty: |$state:ident:$State:ty, $words:ident|$expr:expr) => {
+        take! { $Type|$state:$State,$words|$expr }
+    };
+}
 
 /// [Take]s instances of [Type] given [TokenIter].
 pub trait Give<'state, Type> {
     /// Implement this to be able to [Give] [Type] from the [TokenIter].
+    /// Advance the stream if returning `Ok<Some<Type>>`.
     fn give <'source: 'state> (&self, words: TokenIter<'source>) -> Perhaps<Type>;
     /// Return custom error on [None].
     fn give_or_fail <'source: 'state, E: Into<Box<dyn std::error::Error>>, F: Fn()->E> (
@@ -59,6 +66,8 @@ pub trait Give<'state, Type> {
 }
 /// [Give]s instances of [Self] given [TokenIter].
 pub trait Take<'state, State>: Sized {
+    /// Implement this to be able to [Take] [Self] from the [TokenIter].
+    /// Advance the stream if returning `Ok<Some<Self>>`.
     fn take <'source: 'state> (state: &State, words: TokenIter<'source>) -> Perhaps<Self>;
     /// Return custom error on [None].
     fn take_or_fail <'source: 'state, E: Into<Box<dyn std::error::Error>>, F: Fn()->E> (
@@ -113,40 +122,6 @@ pub trait Take<'state, State>: Sized {
     };
 }
 
-#[cfg(feature="dsl")]
-impl<'state, E: 'state, State: Give<'state, Box<dyn Render<E> + 'state>>>
-Take<'state, State> for Box<dyn Render<E> + 'state> {
-    fn take <'source: 'state> (state: &State, words: TokenIter<'source>) -> Perhaps<Self> {
-        state.give(words)
-    }
-}
-
-/// Implement the [Give] trait, which boils down to
-/// specifying two types and providing an expression.
-#[macro_export] macro_rules! from_dsl {
-    (@a: $T:ty: |$state:ident, $words:ident|$expr:expr) => {
-        impl<'state, State, A: Take<'state, State>> Take<'state, State> for $T {
-            fn take <'source: 'state> ($state: &State, mut $words:TokenIter<'source>) -> Perhaps<$T> {
-                $expr
-            }
-        }
-    };
-    (@ab: $T:ty: |$state:ident, $words:ident|$expr:expr) => {
-        impl<'state, State, A: Take<'state, State>, B: Take<'state, State>> Take<'state, State> for $T {
-            fn take <'source: 'state> ($state: &State, mut $words:TokenIter<'source>) -> Perhaps<$T> {
-                $expr
-            }
-        }
-    };
-    ($T:ty: |$state:ident:$S:ty, $words:ident|$expr:expr) => {
-        impl<'state> Take<'state, $S> for $T {
-            fn take <'source: 'state> ($state: &$S, mut $words:TokenIter<'source>) -> Perhaps<$T> {
-                $expr
-            }
-        }
-    };
-}
-
 // auto impl graveyard:
 
 //impl<'state, State: Give<Type>, Type: 'state> Take<'state, State> for Type {
@@ -157,8 +132,16 @@ Take<'state, State> for Box<dyn Render<E> + 'state> {
     //}
 //}
 
-//impl<'state, Type: Take<'state, State>, State> Give<Type> for State {
+//#[cfg(feature="dsl")]
-    //fn take <'state> (&self, mut words:TokenIter<'source>) -> Perhaps<Type> {
+//impl<'state, E: 'state, State: Give<'state, Box<dyn Render<E> + 'state>>>
-        //Type::take(self, words)
+//Take<'state, State> for Box<dyn Render<E> + 'state> {
+    //fn take <'source: 'state> (state: &State, words: TokenIter<'source>) -> Perhaps<Self> {
+        //state.give(words)
     //}
 //}
+
+impl<'state, Type: Take<'state, State>, State> Give<'state, Type> for State {
+    fn give <'source: 'state> (&self, words: TokenIter<'source>) -> Perhaps<Type> {
+        Type::take(self, words)
+    }
+}

proc/src/proc_expose.rs

@@ -84,14 +84,6 @@ impl ToTokens for ExposeImpl {
                 quote! { Some(::tengri::dsl::Value::Sym(#key)) => state.#value(), }
             });
             write_quote_to(out, quote! {
-                /// Generated by [tengri_proc::expose].
-                impl<'n> ::tengri::dsl::Give<'n, #t> for #state {
-                    fn give <'source: 'n> (
-                        &self, words: ::tengri::dsl::TokenIter<'source>
-                    ) -> Perhaps<#t> {
-                        Take::take(self, words)
-                    }
-                }
                 /// Generated by [tengri_proc::expose].
                 impl<'n> ::tengri::dsl::Take<'n, #state> for #t {
                     fn take <'source: 'n> (

proc/src/proc_view.rs

@@ -43,7 +43,7 @@ impl ToTokens for ViewDef {
         let self_ty = &block.self_ty;
         // Expressions are handled by built-in functions
         // that operate over constants and symbols.
-        let builtin = builtins_with_types().map(|ty|write_quote(quote! { #ty }));
+        let builtin = builtins_with_boxes_output(quote! { #output });
         // Symbols are handled by user-taked functions
         // that take no parameters but `&self`.
         let exposed = exposed.iter().map(|(key, value)|write_quote(quote! {
@@ -52,18 +52,18 @@ impl ToTokens for ViewDef {
         write_quote_to(out, quote! {
             /// Generated by [tengri_proc].
             ///
-            /// Gives [#self_ty] the ability to construct the [Render]able
+            /// Makes [#self_ty] able to construct the [Render]able
-            /// which might corresponds to a given [TokenStream],
+            /// which might correspond to a given [TokenStream],
             /// while taking [#self_ty]'s state into consideration.
-            impl<'state> Give<'state, Box<dyn Render<#output> + 'state>> for #self_ty {
+            impl<'state: 'static> Take<'state, #self_ty> for Box<dyn Render<#output> + 'state> {
-                fn give <'source: 'state> (&self, mut words: TokenIter<'source>)
+                fn take <'source: 'state> (state: &#self_ty, mut words: TokenIter<'source>)
                     -> Perhaps<Box<dyn Render<#output> + 'state>>
                 {
-                    let state = self;
+                    //let state = self;
                     Ok(if let Some(::tengri::dsl::Token { value, .. }) = words.peek() {
                         match value {
                             #(::tengri::dsl::Value::Exp(_, expr) => {
-                                #builtin::take(state, expr)?.map(|value|value.boxed())
+                                Give::<'state, #builtin>::give(state, expr)?.map(|value|value.boxed())
                             },)*
                             #(
                                 #exposed,
@@ -91,21 +91,33 @@ impl ToTokens for ViewDef {
     }
 }
 
-fn builtins_with_types () -> impl Iterator<Item=TokenStream2> {
+fn builtins_with_holes () -> impl Iterator<Item=TokenStream2> {
+    builtins_with(quote! { _ }, quote! { _ })
+}
+
+fn builtins_with_boxes () -> impl Iterator<Item=TokenStream2> {
+    builtins_with(quote! { _ }, quote! { Box<dyn Render<_>+'state> })
+}
+
+fn builtins_with_boxes_output (o: TokenStream2) -> impl Iterator<Item=TokenStream2> {
+    builtins_with(quote! { _ }, quote! { Box<dyn Render<#o>+'state> })
+}
+
+fn builtins_with (n: TokenStream2, c: TokenStream2) -> impl Iterator<Item=TokenStream2> {
     [
-        quote! { When::<      Box<dyn Render<_>>                         > },
+        quote! { When::<       #c    > },
-        quote! { Either::<    Box<dyn Render<_>>, Box<dyn Render<_>>> },
+        quote! { Either::<     #c, #c> },
-        quote! { Align::<     Box<dyn Render<_>>                    > },
+        quote! { Align::<      #c    > },
-        quote! { Bsp::<       Box<dyn Render<_>>, Box<dyn Render<_>>> },
+        quote! { Bsp::<        #c, #c> },
-        quote! { Fill::<      Box<dyn Render<_>>                         > },
+        quote! { Fill::<       #c    > },
-        quote! { Fixed::<_,   Box<dyn Render<_>>                         > },
+        quote! { Fixed::<#n,   #c    > },
-        quote! { Min::<_,     Box<dyn Render<_>>                         > },
+        quote! { Min::<#n,     #c    > },
-        quote! { Max::<_,     Box<dyn Render<_>>                         > },
+        quote! { Max::<#n,     #c    > },
-        quote! { Shrink::<_,  Box<dyn Render<_>>                         > },
+        quote! { Shrink::<#n,  #c    > },
-        quote! { Expand::<_,  Box<dyn Render<_>>                         > },
+        quote! { Expand::<#n,  #c    > },
-        quote! { Push::<_,    Box<dyn Render<_>>                         > },
+        quote! { Push::<#n,    #c    > },
-        quote! { Pull::<_,    Box<dyn Render<_>>                         > },
+        quote! { Pull::<#n,    #c    > },
-        quote! { Margin::<_,  Box<dyn Render<_>>                         > },
+        quote! { Margin::<#n,  #c    > },
-        quote! { Padding::<_, Box<dyn Render<_>>                         > },
+        quote! { Padding::<#n, #c    > },
     ].into_iter()
 }