Add new crate num-derive as an new replacement for num-macro

.travis/test_nightly.sh

@@ -5,6 +5,7 @@ set -ex
 cargo bench --verbose
 
 cargo test --verbose --manifest-path=macros/Cargo.toml
+cargo test --verbose --manifest-path=derive/Cargo.toml
 
 # Build test for the serde feature
 cargo build --verbose --features "serde"

derive/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+authors = ["The Rust Project Developers"]
+description = "Numeric syntax extensions"
+documentation = "http://rust-num.github.io/num"
+homepage = "https://github.com/rust-num/num"
+keywords = ["mathematics", "numerics"]
+license = "MIT/Apache-2.0"
+name = "num-derive"
+repository = "https://github.com/rust-num/num"
+version = "0.1.33"
+
+[dependencies]
+quote = "0.1.3"
+syn = "0.7.0"
+
+[dev-dependencies]
+compiletest_rs = "0.2.2"
+
+[dev-dependencies.num]
+path = ".."
+version = "0.1"
+
+[lib]
+crate-type = ["rustc-macro"]
+name = "num_derive"
+rustc-macro = true
+test = false

derive/src/lib.rs

@@ -0,0 +1,76 @@
+// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_type = "rustc-macro"]
+#![feature(rustc_macro, rustc_macro_lib)]
+
+extern crate syn;
+#[macro_use]
+extern crate quote;
+extern crate rustc_macro;
+
+use rustc_macro::TokenStream;
+
+use syn::Body::Enum;
+use syn::VariantData::Unit;
+
+#[rustc_macro_derive(FromPrimitive)]
+pub fn from_primitive(input: TokenStream) -> TokenStream {
+    let source = input.to_string();
+
+    let ast = syn::parse_macro_input(&source).unwrap();
+    let name = &ast.ident;
+
+    let variants = match ast.body {
+        Enum(ref variants) => variants,
+        _ => {
+            panic!("`FromPrimitive` can be applied only to the enums, {} is not an enum",
+                   name)
+        }
+    };
+
+    let mut idx = 0;
+    let variants: Vec<_> = variants.iter()
+        .map(|variant| {
+            let ident = &variant.ident;
+            match variant.data {
+                Unit => (),
+                _ => {
+                    panic!("`FromPrimitive` can be applied only to unitary enums, {}::{} is either struct or tuple", name, ident)
+                },
+            }
+            if let Some(val) = variant.discriminant {
+                idx = val.value;
+            }
+            let tt = quote!(#idx => Some(#name::#ident));
+            idx += 1;
+            tt
+        })
+        .collect();
+
+    let res = quote! {
+        #ast
+
+        impl ::num::traits::FromPrimitive for #name {
+            fn from_i64(n: i64) -> Option<Self> {
+                Self::from_u64(n as u64)
+            }
+
+            fn from_u64(n: u64) -> Option<Self> {
+                match n {
+                    #(variants,)*
+                    _ => None,
+                }
+            }
+        }
+    };
+
+    res.to_string().parse().unwrap()
+}

derive/tests/compile-fail/derive_on_struct.rs

@@ -13,7 +13,7 @@
 
 extern crate num;
 #[macro_use]
-extern crate num_macros;
+extern crate num_derive;
 
 #[derive(Debug, PartialEq, FromPrimitive)] //~ ERROR
 struct Color {

derive/tests/compile-fail/enum_with_associated_data.rs

@@ -13,7 +13,7 @@
 
 extern crate num;
 #[macro_use]
-extern crate num_macros;
+extern crate num_derive;
 
 #[derive(Debug, PartialEq, FromPrimitive)] //~ ERROR
 enum Color {

derive/tests/empty_enum.rs

@@ -13,7 +13,7 @@
 
 extern crate num;
 #[macro_use]
-extern crate num_macros;
+extern crate num_derive;
 
 #[derive(Debug, PartialEq, FromPrimitive)]
 enum Color {}

derive/tests/trivial.rs

@@ -12,7 +12,7 @@
 
 extern crate num;
 #[macro_use]
-extern crate num_macros;
+extern crate num_derive;
 
 #[derive(Debug, PartialEq, FromPrimitive)]
 enum Color {

derive/tests/with_custom_values.rs

@@ -12,7 +12,7 @@
 
 extern crate num;
 #[macro_use]
-extern crate num_macros;
+extern crate num_derive;
 
 #[derive(Debug, PartialEq, FromPrimitive)]
 enum Color {

macros/Cargo.toml

@@ -1,27 +1,17 @@
 [package]
-authors = ["The Rust Project Developers"]
-description = "Numeric syntax extensions"
-documentation = "http://rust-num.github.io/num"
-homepage = "https://github.com/rust-num/num"
-keywords = ["mathematics", "numerics"]
-license = "MIT/Apache-2.0"
 name = "num-macros"
-repository = "https://github.com/rust-num/num"
 version = "0.1.33"
-
-[dependencies]
-quote = "0.1.3"
-syn = "0.6.0"
-
-[dev-dependencies]
-compiletest_rs = "0.2.2"
-
-[dev-dependencies.num]
-path = ".."
-version = "0.1"
+authors = ["The Rust Project Developers"]
+license = "MIT/Apache-2.0"
+homepage = "https://github.com/rust-num/num"
+repository = "https://github.com/rust-num/num"
+documentation = "http://rust-num.github.io/num"
+keywords = ["mathematics", "numerics"]
+description = "Numeric syntax extensions"
 
 [lib]
-crate-type = ["rustc-macro"]
 name = "num_macros"
-rustc-macro = true
-test = false
+plugin = true
+
+[dev-dependencies]
+num = { path = "..", version = "0.1" }

macros/src/lib.rs

@@ -8,69 +8,194 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![crate_type = "rustc-macro"]
-#![feature(rustc_macro, rustc_macro_lib)]
+#![feature(plugin_registrar, rustc_private)]
 
-extern crate syn;
-#[macro_use]
-extern crate quote;
-extern crate rustc_macro;
+extern crate syntax;
+extern crate syntax_ext;
+extern crate rustc_plugin;
 
-use rustc_macro::TokenStream;
+use syntax::ast::{MetaItem, Expr, BinOpKind};
+use syntax::ast;
+use syntax::codemap::Span;
+use syntax::ext::base::{ExtCtxt, Annotatable};
+use syntax::ext::build::AstBuilder;
+use syntax_ext::deriving::generic::*;
+use syntax_ext::deriving::generic::ty::*;
+use syntax::parse::token::InternedString;
+use syntax::ptr::P;
+use syntax::ext::base::MultiDecorator;
+use syntax::parse::token;
 
-use syn::Body::Enum;
-use syn::VariantData::Unit;
+use rustc_plugin::Registry;
 
-#[rustc_macro_derive(FromPrimitive)]
-pub fn from_primitive(input: TokenStream) -> TokenStream {
-    let source = input.to_string();
+macro_rules! pathvec {
+    ($($x:ident)::+) => (
+        vec![ $( stringify!($x) ),+ ]
+    )
+}
 
-    let ast = syn::parse_macro_input(&source).unwrap();
-    let name = &ast.ident;
+macro_rules! path {
+    ($($x:tt)*) => (
+        ::syntax_ext::deriving::generic::ty::Path::new( pathvec!( $($x)* ) )
+    )
+}
 
-    let variants = match ast.body {
-        Enum(ref variants) => variants,
-        _ => {
-            panic!("`FromPrimitive` can be applied only to the enums, {} is not an enum",
-                   name)
+macro_rules! path_local {
+    ($x:ident) => (
+        ::syntax_ext::deriving::generic::ty::Path::new_local(stringify!($x))
+    )
+}
+
+macro_rules! pathvec_std {
+    ($cx:expr, $first:ident :: $($rest:ident)::+) => ({
+        let mut v = pathvec!($($rest)::+);
+        if let Some(s) = $cx.crate_root {
+            v.insert(0, s);
         }
+        v
+    })
+}
+
+pub fn expand_deriving_from_primitive(cx: &mut ExtCtxt,
+                                      span: Span,
+                                      mitem: &MetaItem,
+                                      item: &Annotatable,
+                                      push: &mut FnMut(Annotatable))
+{
+    let inline = cx.meta_word(span, InternedString::new("inline"));
+    let attrs = vec!(cx.attribute(span, inline));
+    let trait_def = TraitDef {
+        is_unsafe: false,
+        span: span,
+        attributes: Vec::new(),
+        path: path!(num::FromPrimitive),
+        additional_bounds: Vec::new(),
+        generics: LifetimeBounds::empty(),
+        methods: vec!(
+            MethodDef {
+                name: "from_i64",
+                is_unsafe: false,
+                unify_fieldless_variants: false,
+                generics: LifetimeBounds::empty(),
+                explicit_self: None,
+                args: vec!(Literal(path_local!(i64))),
+                ret_ty: Literal(Path::new_(pathvec_std!(cx, core::option::Option),
+                                           None,
+                                           vec!(Box::new(Self_)),
+                                           true)),
+                // #[inline] liable to cause code-bloat
+                attributes: attrs.clone(),
+                combine_substructure: combine_substructure(Box::new(|c, s, sub| {
+                    cs_from("i64", c, s, sub)
+                })),
+            },
+            MethodDef {
+                name: "from_u64",
+                is_unsafe: false,
+                unify_fieldless_variants: false,
+                generics: LifetimeBounds::empty(),
+                explicit_self: None,
+                args: vec!(Literal(path_local!(u64))),
+                ret_ty: Literal(Path::new_(pathvec_std!(cx, core::option::Option),
+                                           None,
+                                           vec!(Box::new(Self_)),
+                                           true)),
+                // #[inline] liable to cause code-bloat
+                attributes: attrs,
+                combine_substructure: combine_substructure(Box::new(|c, s, sub| {
+                    cs_from("u64", c, s, sub)
+                })),
+            }
+        ),
+        associated_types: Vec::new(),
+        supports_unions: false,
     };
 
-    let mut idx = 0;
-    let variants: Vec<_> = variants.iter()
-        .map(|variant| {
-            let ident = &variant.ident;
-            match variant.data {
-                Unit => (),
-                _ => {
-                    panic!("`FromPrimitive` can be applied only to unitary enums, {}::{} is either struct or tuple", name, ident)
-                },
-            }
-            if let Some(val) = variant.discriminant {
-                idx = val.value;
-            }
-            let tt = quote!(#idx => Some(#name::#ident));
-            idx += 1;
-            tt
-        })
-        .collect();
+    trait_def.expand(cx, mitem, &item, push)
+}
 
-    let res = quote! {
-        #ast
+fn cs_from(name: &str, cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
+    if substr.nonself_args.len() != 1 {
+        cx.span_bug(trait_span, "incorrect number of arguments in `derive(FromPrimitive)`")
+    }
 
-        impl ::num::traits::FromPrimitive for #name {
-            fn from_i64(n: i64) -> Option<Self> {
-                Self::from_u64(n as u64)
+    let n = &substr.nonself_args[0];
+
+    match *substr.fields {
+        StaticStruct(..) => {
+            cx.span_err(trait_span, "`FromPrimitive` cannot be derived for structs");
+            return cx.expr_fail(trait_span, InternedString::new(""));
+        }
+        StaticEnum(enum_def, _) => {
+            if enum_def.variants.is_empty() {
+                cx.span_err(trait_span,
+                            "`FromPrimitive` cannot be derived for enums with no variants");
+                return cx.expr_fail(trait_span, InternedString::new(""));
             }
 
-            fn from_u64(n: u64) -> Option<Self> {
-                match n {
-                    #(variants,)*
-                    _ => None,
+            let mut arms = Vec::new();
+
+            for variant in &enum_def.variants {
+                match variant.node.data {
+                    ast::VariantData::Unit(..) => {
+                        let span = variant.span;
+
+                        // expr for `$n == $variant as $name`
+                        let path = cx.path(span, vec![substr.type_ident, variant.node.name]);
+                        let variant = cx.expr_path(path);
+                        let ty = cx.ty_ident(span, cx.ident_of(name));
+                        let cast = cx.expr_cast(span, variant.clone(), ty);
+                        let guard = cx.expr_binary(span, BinOpKind::Eq, n.clone(), cast);
+
+                        // expr for `Some($variant)`
+                        let body = cx.expr_some(span, variant);
+
+                        // arm for `_ if $guard => $body`
+                        let arm = ast::Arm {
+                            attrs: vec!(),
+                            pats: vec!(cx.pat_wild(span)),
+                            guard: Some(guard),
+                            body: body,
+                        };
+
+                        arms.push(arm);
+                    }
+                    ast::VariantData::Tuple(..) => {
+                        cx.span_err(trait_span,
+                                    "`FromPrimitive` cannot be derived for \
+                                    enum variants with arguments");
+                        return cx.expr_fail(trait_span,
+                                            InternedString::new(""));
+                    }
+                    ast::VariantData::Struct(..) => {
+                        cx.span_err(trait_span,
+                                    "`FromPrimitive` cannot be derived for enums \
+                                    with struct variants");
+                        return cx.expr_fail(trait_span,
+                                            InternedString::new(""));
+                    }
                 }
             }
-        }
-    };
 
-    res.to_string().parse().unwrap()
+            // arm for `_ => None`
+            let arm = ast::Arm {
+                attrs: vec!(),
+                pats: vec!(cx.pat_wild(trait_span)),
+                guard: None,
+                body: cx.expr_none(trait_span),
+            };
+            arms.push(arm);
+
+            cx.expr_match(trait_span, n.clone(), arms)
+        }
+        _ => cx.span_bug(trait_span, "expected StaticEnum in derive(FromPrimitive)")
+    }
+}
+
+#[plugin_registrar]
+#[doc(hidden)]
+pub fn plugin_registrar(reg: &mut Registry) {
+    reg.register_syntax_extension(
+        token::intern("derive_NumFromPrimitive"),
+        MultiDecorator(Box::new(expand_deriving_from_primitive)));
 }

macros/tests/test_macro.rs

@@ -0,0 +1,36 @@
+// Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(custom_derive, plugin)]
+#![plugin(num_macros)]
+
+extern crate num;
+
+#[derive(Debug, PartialEq, NumFromPrimitive)]
+enum Color {
+    Red,
+    Blue,
+    Green,
+}
+
+#[test]
+fn test_from_primitive() {
+    let v: Vec<Option<Color>> = vec![
+        num::FromPrimitive::from_u64(0),
+        num::FromPrimitive::from_u64(1),
+        num::FromPrimitive::from_u64(2),
+        num::FromPrimitive::from_u64(3),
+    ];
+
+    assert_eq!(
+        v,
+        vec![Some(Color::Red), Some(Color::Blue), Some(Color::Green), None]
+    );
+}