feat: added macro to automatically match input values for a specific pattern

Author: raphael-goetz

taurus/src/context/macros.rs

@@ -0,0 +1,45 @@
+/// Pulls typed parameters from a slice of `Argument` using your `TryFromArgument`
+/// impls. Fails early with your `Signal::Failure(RuntimeError::simple(...))`.
+macro_rules! args {
+    ($args_ident:ident => $( $name:ident : $ty:ty ),+ $(,)?) => {
+        // Arity check
+        let __expected: usize = 0usize $(+ { let _ = ::core::any::type_name::<$ty>(); 1usize })*;
+        if $args_ident.len() != __expected {
+            return $crate::context::signal::Signal::Failure(
+                $crate::error::RuntimeError::simple(
+                    "InvalidArgumentRuntimeError",
+                    format!("Expected {__expected} args but received {}", $args_ident.len()),
+                )
+            );
+        }
+
+        // Typed extraction
+        let mut __i: usize = 0;
+        $(
+            let $name: $ty = match <
+                $ty as $crate::context::argument::TryFromArgument
+            >::try_from_argument(& $args_ident[__i]) {
+                Ok(v) => v,
+                Err(sig) => return sig,
+            };
+            __i += 1;
+        )+
+    };
+}
+
+/// Asserts there are no arguments.
+macro_rules! no_args {
+    ($args_ident:ident) => {
+        if !$args_ident.is_empty() {
+            return $crate::context::signal::Signal::Failure(
+                $crate::error::RuntimeError::simple(
+                    "InvalidArgumentRuntimeError",
+                    format!("Expected 0 args but received {}", $args_ident.len()),
+                )
+            );
+        }
+    };
+}
+
+pub(crate) use args;
+pub(crate) use no_args;