start implementing edn loader; remove PhantomData from some tek_layout constructs

engine/Cargo.toml

@@ -7,3 +7,4 @@ version = "0.2.0"
 crossterm = "0.28.1"
 ratatui = { version = "0.29.0", features = [ "unstable-widget-ref", "underline-color" ] }
 better-panic = "0.3.0"
+clojure-reader = "0.3.0"

engine/src/edn.rs

@@ -0,0 +1,36 @@
+use crate::*;
+
+use std::sync::{Arc, RwLock};
+use std::collections::BTreeMap;
+
+pub use clojure_reader::edn::Edn;
+
+/// EDN parsing helper.
+#[macro_export] macro_rules! edn {
+    ($edn:ident { $($pat:pat => $expr:expr),* $(,)? }) => {
+        match $edn { $($pat => $expr),* }
+    };
+    ($edn:ident in $args:ident { $($pat:pat => $expr:expr),* $(,)? }) => {
+        for $edn in $args {
+            edn!($edn { $($pat => $expr),* })
+        }
+    };
+}
+
+pub trait FromEdn<C>: Sized {
+    const ID: &'static str;
+    fn from_edn (context: C, expr: &[Edn<'_>]) -> Usually<Self>;
+}
+
+/// Implements the [FromEdn] trait.
+#[macro_export] macro_rules! from_edn {
+    ($id:expr => |$context:tt:$Context:ty, $args:ident| -> $T:ty $body:block) => {
+        impl FromEdn<$Context> for $T {
+            const ID: &'static str = $id;
+            fn from_edn <'e> ($context: $Context, $args: &[Edn<'e>]) -> Usually<Self> {
+                $body
+            }
+        }
+    }
+}
+

engine/src/lib.rs

@@ -4,6 +4,7 @@ mod input;  pub use self::input::*;
 mod output; pub use self::output::*;
 
 pub mod tui;
+pub mod edn;
 
 pub use std::error::Error;