RFC: Allow a re-export for main

text/0000-main-reexport.md

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+- Feature Name: main_reexport
+- Start Date: 2015-08-19
+- RFC PR: (leave this empty)
+- Rust Issue: (leave this empty)
+
+# Summary
+
+Allow a re-export of a function as entry point `main`.
+
+# Motivation
+
+Functions and re-exports of functions usually behave the same way, but they do
+not for the program entry point `main`. This RFC aims to fix this inconsistency.
+
+The above mentioned inconsistency means that e.g. you currently cannot use a
+library's exported function as your main function.
+
+Example:
+
+    pub mod foo {
+        pub fn bar() {
+            println!("Hello world!");
+        }
+    }
+    use foo::bar as main;
+
+Example 2:
+
+    extern crate main_functions;
+    pub use main_functions::rmdir as main;
+
+See also https://github.com/rust-lang/rust/issues/27640 for the corresponding
+issue discussion.
+
+The `#[main]` attribute can also be used to change the entry point of the
+generated binary. This is largely irrelevant for this RFC as this RFC tries to
+fix an inconsistency with re-exports and directly defined functions.
+Nevertheless, it can be pointed out that the `#[main]` attribute does not cover
+all the above-mentioned use cases.
+
+# Detailed design
+
+Use the symbol `main` at the top-level of a crate that is compiled as a program
+(`--crate-type=bin`) – instead of explicitly only accepting directly-defined
+functions, also allow (possibly non-`pub`) re-exports.
+
+# Drawbacks
+
+None.
+
+# Alternatives
+
+None.
+
+# Unresolved questions
+
+None.