feat: scaffold crate structure and implement core macros

Add the project skeleton, LICENSE files, README, Makefile, doc
examples, and the initial implementation of `#[func]`, `invoke!`,
and `select!` procedural macros.

1 files changed, 10 insertions, 0 deletions

diff --git a/doc/usage/invoke.rs b/doc/usage/invoke.rs
new file mode 100644
index 0000000..0ae90d2
--- /dev/null
+++ b/doc/usage/invoke.rs
@@ -0,0 +1,10 @@
+#[func]
+fn compute(x: i32) -> i32 {
+    x * 2
+}
+
+#[func]
+fn example() -> i32 {
+    // invoke! macro should be used with #[func]
+    invoke!(compute(5))
+}