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authorRobin Krahl <robin.krahl@ireas.org>2020-01-07 11:18:04 +0000
committerDaniel Mueller <deso@posteo.net>2020-01-08 09:20:25 -0800
commit5e20a29b4fdc8a2d442d1093681b396dcb4b816b (patch)
tree55ab083fa8999d2ccbb5e921c1ffe52560dca152 /syn-mid/examples/const_fn
parent203e691f46d591a2cc8acdfd850fa9f5b0fb8a98 (diff)
downloadnitrocli-5e20a29b4fdc8a2d442d1093681b396dcb4b816b.tar.gz
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Add structopt dependency in version 0.3.7
This patch series replaces argparse with structopt in the argument handling code. As a first step, we need structopt as a dependency. Import subrepo structopt/:structopt at efbdda4753592e27bc430fb01f7b9650b2f3174d Import subrepo bitflags/:bitflags at 30668016aca6bd3b02c766e8347e0b4080d4c296 Import subrepo clap/:clap at 784524f7eb193e35f81082cc69454c8c21b948f7 Import subrepo heck/:heck at 093d56fbf001e1506e56dbfa38631d99b1066df1 Import subrepo proc-macro-error/:proc-macro-error at 6c4cfe79a622c5de8ae68557993542be46eacae2 Import subrepo proc-macro2/:proc-macro2 at d5d48eddca4566e5438e8a2cbed4a74e049544de Import subrepo quote/:quote at 727436c6c137b20f0f34dde5d8fda2679b9747ad Import subrepo rustversion/:rustversion at 0c5663313516263059ce9059ef81fc7a1cf655ca Import subrepo syn-mid/:syn-mid at 5d3d85414a9e6674e1857ec22a87b96e04a6851a Import subrepo syn/:syn at e87c27e87f6f4ef8919d0372bdb056d53ef0d8f3 Import subrepo textwrap/:textwrap at abcd618beae3f74841032aa5b53c1086b0a57ca2 Import subrepo unicode-segmentation/:unicode-segmentation at 637c9874c4fe0c205ff27787faf150a40295c6c3 Import subrepo unicode-width/:unicode-width at 3033826f8bf05e82724140a981d5941e48fce393 Import subrepo unicode-xid/:unicode-xid at 4baae9fffb156ba229665b972a9cd5991787ceb7
Diffstat (limited to 'syn-mid/examples/const_fn')
-rw-r--r--syn-mid/examples/const_fn/Cargo.toml16
-rw-r--r--syn-mid/examples/const_fn/lib.rs31
2 files changed, 47 insertions, 0 deletions
diff --git a/syn-mid/examples/const_fn/Cargo.toml b/syn-mid/examples/const_fn/Cargo.toml
new file mode 100644
index 0000000..d823e76
--- /dev/null
+++ b/syn-mid/examples/const_fn/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "const_fn"
+version = "0.0.0"
+authors = ["Taiki Endo <te316e89@gmail.com>"]
+edition = "2018"
+publish = false
+
+[lib]
+proc-macro = true
+path = "lib.rs"
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0"
+syn-mid = { version = "0.4", path = "../..", features = ["clone-impls"] }
diff --git a/syn-mid/examples/const_fn/lib.rs b/syn-mid/examples/const_fn/lib.rs
new file mode 100644
index 0000000..29255f2
--- /dev/null
+++ b/syn-mid/examples/const_fn/lib.rs
@@ -0,0 +1,31 @@
+#![warn(rust_2018_idioms)]
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use proc_macro2::TokenStream as TokenStream2;
+use quote::quote;
+use syn_mid::ItemFn;
+
+/// An attribute for easy generation of a const function with conditional compilations.
+#[proc_macro_attribute]
+pub fn const_fn(args: TokenStream, function: TokenStream) -> TokenStream {
+ assert!(!args.is_empty(), "requires an argument");
+
+ let mut function = syn::parse_macro_input!(function as ItemFn);
+ let mut const_function = function.clone();
+
+ if function.constness.is_some() {
+ function.constness = None;
+ } else {
+ const_function.constness = Some(Default::default());
+ }
+
+ let args = TokenStream2::from(args);
+ TokenStream::from(quote! {
+ #[cfg(not(#args))]
+ #function
+ #[cfg(#args)]
+ #const_function
+ })
+}