Merge pull request #32 from alecmocatta/nameable

Nameable closures v0.2

Author: mergify[bot]

Cargo.toml

@@ -2,7 +2,7 @@
 
 [package]
 name = "serde_closure"
-version = "0.3.1"
+version = "0.3.2"
 license = "MIT OR Apache-2.0"
 authors = ["Alec Mocatta <[email protected]>"]
 categories = ["development-tools","encoding","rust-patterns","network-programming"]
@@ -23,7 +23,7 @@ azure-devops = { project = "alecmocatta/serde_closure", pipeline = "tests", buil
 maintenance = { status = "actively-developed" }
 
 [dependencies]
-serde_closure_derive = { version = "=0.3.1", path = "serde_closure_derive" }
+serde_closure_derive = { version = "=0.3.2", path = "serde_closure_derive" }
 serde = { version = "1.0", features = ["derive"] }
 
 [build-dependencies]

azure-pipelines.yml

@@ -13,8 +13,8 @@ jobs:
   parameters:
     endpoint: alecmocatta
     default:
-      rust_toolchain: beta nightly
-      rust_lint_toolchain: nightly-2020-07-12
+      rust_toolchain: stable nightly
+      rust_lint_toolchain: nightly-2020-07-27
       rust_flags: ''
       rust_features_clippy: ''
       rust_features: ''

serde_closure_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_closure_derive"
-version = "0.3.1"
+version = "0.3.2"
 license = "MIT OR Apache-2.0"
 authors = ["Alec Mocatta <[email protected]>"]
 categories = ["development-tools","encoding","rust-patterns","network-programming"]
@@ -27,4 +27,4 @@ proc-macro = true
 [dependencies]
 proc-macro2 = { version = "1.0.1", default-features = false }
 quote = { version = "1.0.2", default-features = false }
-syn = { version = "1.0.5", default-features = false, features = ["clone-impls", "full", "parsing", "printing", "proc-macro", "visit-mut"] }
+syn = { version = "1.0.38", default-features = false, features = ["clone-impls", "full", "parsing", "printing", "proc-macro", "visit-mut"] }

serde_closure_derive/src/lib.rs

@@ -10,13 +10,13 @@
 //! See [`serde_closure`](https://docs.rs/serde_closure) for
 //! documentation.
 
-#![doc(html_root_url = "https://docs.rs/serde_closure_derive/0.3.1")]
+#![doc(html_root_url = "https://docs.rs/serde_closure_derive/0.3.2")]
 
 use proc_macro2::{Span, TokenStream};
 use quote::{quote, ToTokens};
 use std::{collections::HashSet, iter, iter::successors, mem::take, str};
 use syn::{
-	parse2, parse_macro_input, visit_mut::{self, VisitMut}, Arm, AttributeArgs, Block, Error, Expr, ExprArray, ExprAssign, ExprAssignOp, ExprAsync, ExprAwait, ExprBinary, ExprBlock, ExprBox, ExprBreak, ExprCall, ExprCast, ExprClosure, ExprField, ExprForLoop, ExprGroup, ExprIf, ExprIndex, ExprLet, ExprLoop, ExprMacro, ExprMatch, ExprMethodCall, ExprParen, ExprPath, ExprRange, ExprReference, ExprRepeat, ExprReturn, ExprStruct, ExprTry, ExprTryBlock, ExprTuple, ExprType, ExprUnary, ExprUnsafe, ExprWhile, ExprYield, FieldValue, Ident, Item, Lifetime, LifetimeDef, Local, Member, Pat, PatBox, PatIdent, PatReference, PatSlice, PatTuple, PatTupleStruct, PatType, Path, PathArguments, PathSegment, ReturnType, Stmt, TraitBound, Type, TypeInfer, TypeReference, TypeTuple, UnOp
+	parse2, parse_macro_input, visit_mut::{self, VisitMut}, Arm, AttributeArgs, Block, Error, Expr, ExprArray, ExprAssign, ExprAssignOp, ExprAsync, ExprAwait, ExprBinary, ExprBlock, ExprBox, ExprBreak, ExprCall, ExprCast, ExprClosure, ExprField, ExprForLoop, ExprGroup, ExprIf, ExprIndex, ExprLet, ExprLoop, ExprMacro, ExprMatch, ExprMethodCall, ExprParen, ExprPath, ExprRange, ExprReference, ExprRepeat, ExprReturn, ExprStruct, ExprTry, ExprTryBlock, ExprTuple, ExprType, ExprUnary, ExprUnsafe, ExprWhile, ExprYield, FieldValue, GenericParam, Ident, ImplItem, Item, ItemImpl, Lifetime, LifetimeDef, Local, Member, Pat, PatBox, PatIdent, PatReference, PatSlice, PatTuple, PatTupleStruct, PatType, Path, PathArguments, PathSegment, ReturnType, Stmt, TraitBound, Type, TypeInfer, TypeReference, TypeTuple, UnOp
 };
 
 #[proc_macro]
@@ -60,14 +60,12 @@ pub fn desugar(
 
 struct Desugar;
 
-impl VisitMut for Desugar {
-	fn visit_trait_bound_mut(&mut self, i: &mut TraitBound) {
-		let span = Span::call_site();
-		if let PathSegment {
-			arguments: PathArguments::Parenthesized(args),
-			..
-		} = i.path.segments.last().unwrap()
-		{
+impl Desugar {
+	fn desugar_path_arg(
+		&mut self, arg: &mut PathArguments, return_output: bool,
+	) -> (u64, Option<Type>) {
+		if let PathArguments::Parenthesized(args) = &arg {
+			let span = Span::call_site();
 			let mut lifetimes = 0;
 			let mut inputs = args.inputs.clone();
 			for input in &mut inputs {
@@ -95,6 +93,25 @@ impl VisitMut for Desugar {
 					elems: Default::default(),
 				}),
 			};
+			*arg = PathArguments::AngleBracketed(if !return_output {
+				syn::parse2(quote! { <(#inputs), Output = #output> }).unwrap()
+			} else {
+				syn::parse2(quote! { <(#inputs)> }).unwrap()
+			});
+			(lifetimes, if return_output { Some(output) } else { None })
+		} else {
+			(0, None)
+		}
+	}
+}
+
+impl VisitMut for Desugar {
+	fn visit_trait_bound_mut(&mut self, i: &mut TraitBound) {
+		let lifetimes = self
+			.desugar_path_arg(&mut i.path.segments.last_mut().unwrap().arguments, false)
+			.0;
+		if lifetimes > 0 {
+			let span = Span::call_site();
 			let empty = syn::parse2(quote! {for <>}).unwrap();
 			i.lifetimes = Some(i.lifetimes.clone().unwrap_or(empty));
 			i.lifetimes
@@ -107,12 +124,35 @@ impl VisitMut for Desugar {
 						span,
 					))
 				}));
-			i.path.segments.last_mut().unwrap().arguments = PathArguments::AngleBracketed(
-				syn::parse2(quote! { <(#inputs), Output = #output> }).unwrap(),
-			);
 		}
 		visit_mut::visit_trait_bound_mut(self, i)
 	}
+	fn visit_item_impl_mut(&mut self, i: &mut ItemImpl) {
+		if let Some((_, path, _)) = &mut i.trait_ {
+			let (lifetimes, output) =
+				self.desugar_path_arg(&mut path.segments.last_mut().unwrap().arguments, true);
+			if lifetimes > 0 {
+				let span = Span::call_site();
+				i.generics.lt_token = Some(Default::default());
+				i.generics.gt_token = Some(Default::default());
+				i.generics.params.extend((0..lifetimes).map(|i| {
+					GenericParam::Lifetime(LifetimeDef::new(Lifetime::new(
+						&format!("'__serde_closure_{}", bijective_base(i, 26, alpha_lower)),
+						span,
+					)))
+				}));
+			}
+			// Yuck
+			if path.segments.last().unwrap().ident == "FnOnce" {
+				if let Some(output) = output {
+					i.items.push(ImplItem::Type(
+						syn::parse2(quote! { type Output = #output; }).unwrap(),
+					));
+				}
+			}
+		}
+		visit_mut::visit_item_impl_mut(self, i)
+	}
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -257,6 +297,7 @@ fn impl_closure(mut closure: ExprClosure, kind: Kind) -> Result<TokenStream, Err
 				F: ops::FnOnce(&#name<#(#type_params,)* ()>,I) -> O
 			{
 				type Output = O;
+
 				#[inline(always)]
 				fn call_once(self, args: I) -> Self::Output {
 					self.f()(&self.strip_f(), args)
@@ -287,6 +328,7 @@ fn impl_closure(mut closure: ExprClosure, kind: Kind) -> Result<TokenStream, Err
 				F: ops::FnOnce(&mut #name<#(#type_params,)* ()>,I) -> O
 			{
 				type Output = O;
+
 				#[inline(always)]
 				fn call_once(mut self, args: I) -> Self::Output {
 					self.f()(&mut self.strip_f(), args)
@@ -308,6 +350,7 @@ fn impl_closure(mut closure: ExprClosure, kind: Kind) -> Result<TokenStream, Err
 				F: ops::FnOnce(#name<#(#type_params,)* ()>,I) -> O
 			{
 				type Output = O;
+
 				#[inline(always)]
 				fn call_once(self, args: I) -> Self::Output {
 					self.f()(self.strip_f(), args)
@@ -787,11 +830,7 @@ impl<'a> State<'a> {
 			{
 				let path_segment = &path.segments.first().unwrap();
 				let ident = &path_segment.ident;
-				let has_path_arguments = if let PathArguments::None = path_segment.arguments {
-					false
-				} else {
-					true
-				};
+				let has_path_arguments = !matches!(path_segment.arguments, PathArguments::None);
 				if !self.variables.contains(ident) {
 					// Assume it's a variable, unless:
 					// * It starts with an upper-case letter, e.g. `Some`, OR