add rylander dithering, `define` macro, begin work on guides.

1 files changed, 18 insertions, 5 deletions

diff --git a/src/lisp/prelude.rs b/src/lisp/prelude.rs
index 4a6a4ed..372bb00 100644
--- a/src/lisp/prelude.rs
+++ b/src/lisp/prelude.rs
@@ -27,6 +27,13 @@ macro_rules! primitive {
 }
 
 #[macro_export]
+macro_rules! define {
+    ($env:expr, $name:expr, $value:expr) => {
+        let _ = $env.insert($name.to_string(), $value);
+    };
+}
+
+#[macro_export]
 macro_rules! type_match {
     ($args:expr, $($range:literal => $kind:pat),+) => {
         {
@@ -54,6 +61,8 @@ macro_rules! type_match {
 pub fn new_env() -> Result<Environment, LispError> {
     let mut env = Environment::new();
 
+    define!(env, "else", LispExpr::BoolLit(true));
+
     primitive!(env, Arity::Atleast(2), "+", |args, _| {
         let nums = args
             .into_iter()
@@ -98,11 +107,6 @@ pub fn new_env() -> Result<Environment, LispError> {
         Ok(LispExpr::Number(acc))
     });
 
-    primitive!(env, Arity::Exact(0), "toggle-grid", |_, app| {
-        app.toggle_grid();
-        Ok(LispExpr::Unit)
-    });
-
     primitive!(env, Arity::Atleast(2), "and", |args, _| {
         if args
             .iter()
@@ -252,6 +256,15 @@ pub fn new_env() -> Result<Environment, LispError> {
         }
     });
 
+    primitive!(env, Arity::Exact(0), "grid-enabled?", |_, app| {
+        Ok(LispExpr::BoolLit(app.grid.enabled))
+    });
+
+    primitive!(env, Arity::Exact(1), "set-grid!", |args, app| {
+        app.grid.enabled = args[0].cast_bool();
+        Ok(LispExpr::Unit)
+    });
+
     primitive!(env, Arity::Exact(0), "brush-fill", |_, app| {
         app.brush = Brush::Fill;
         return Ok(LispExpr::Unit);