5 files changed, 63 insertions, 6 deletions

diff --git a/src/app.rs b/src/app.rs
index 1263324..377c613 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -662,6 +662,11 @@ impl<'ctx> AppState<'ctx> {
                                             self.apply_operation(op, OpKind::Undo);
                                         }
                                     }
+                                    Keycode::R => {
+                                        if let Some(op) = self.undo_stack.redo() {
+                                            self.apply_operation(op, OpKind::Redo);
+                                        }
+                                    }
                                     // export to file
                                     Keycode::N => {
                                         let image = self.export();
@@ -670,11 +675,6 @@ impl<'ctx> AppState<'ctx> {
                                         eprintln!("writing to file");
                                         buffer.write_all(&encoded[..]).unwrap();
                                     }
-                                    Keycode::R => {
-                                        if let Some(op) = self.undo_stack.redo() {
-                                            self.apply_operation(op, OpKind::Redo);
-                                        }
-                                    }
                                     _ => (),
                                 }
                             }
diff --git a/src/lisp/error.rs b/src/lisp/error.rs
index f905e6d..f323bb8 100644
--- a/src/lisp/error.rs
+++ b/src/lisp/error.rs
@@ -1,6 +1,7 @@
 use crate::lisp::{
     expr::{Arity, LispExpr},
     lex::{Span, SpanDisplay},
+    number::LispNumber,
 };
 
 use std::{fmt, io};
@@ -98,6 +99,7 @@ pub enum EvalError {
     TypeMismatch,
     NoFileName,
     AccessEmptyList,
+    InvalidCoordinates((LispNumber, LispNumber)),
     AssertionError { expected: LispExpr, got: LispExpr },
     ScriptLoadError(io::Error),
     CustomInternal(&'static str),
@@ -125,6 +127,7 @@ impl fmt::Display for EvalError {
             Self::DivByZero => write!(f, "attempt to divide by zero"),
             Self::NoFileName => write!(f, "no file name specified"),
             Self::AccessEmptyList => write!(f, "attempted to access empty list"),
+            Self::InvalidCoordinates((x, y)) => write!(f, "invalid coordinates: {} {}", x, y),
             Self::AssertionError { expected, got } => {
                 write!(f, "assertion error: expected `{}` got `{}`", expected, got)
             }
diff --git a/src/lisp/number.rs b/src/lisp/number.rs
index 0ce5ac0..4ca890a 100644
--- a/src/lisp/number.rs
+++ b/src/lisp/number.rs
@@ -26,6 +26,12 @@ impl LispNumber {
             });
         }
     }
+    pub fn unwrap_integer(self) -> i64 {
+        match self {
+            Self::Integer(x) => x,
+            Self::Float(x) => x.floor() as i64, // lossy
+        }
+    }
 }
 
 impl Add for LispNumber {
diff --git a/src/lisp/prelude.rs b/src/lisp/prelude.rs
index 54c831f..4a6a4ed 100644
--- a/src/lisp/prelude.rs
+++ b/src/lisp/prelude.rs
@@ -1,4 +1,5 @@
 use crate::{
+    bitmap::MapPoint,
     brush::Brush,
     lisp::{
         error::{EvalError, LispError},
@@ -7,6 +8,7 @@ use crate::{
         Environment,
     },
     primitive,
+    undo::PaintRecord,
     utils::load_script,
 };
 
@@ -39,7 +41,8 @@ macro_rules! type_match {
         {
             let mut temp_vec = vec![];
             $(
-                for arg in &$args[$range] {
+                let arg_range: &[LispExpr] = &$args[$range];
+                for arg in arg_range {
                     temp_vec.push(matches!(arg, $kind));
                 }
             )+
@@ -334,5 +337,44 @@ pub fn new_env() -> Result<Environment, LispError> {
         }
     });
 
+    primitive!(env, Arity::Exact(0), "canvas-width", |_, app| {
+        return Ok(LispExpr::Number(LispNumber::Integer(app.width() as i64)));
+    });
+
+    primitive!(env, Arity::Exact(0), "canvas-height", |_, app| {
+        return Ok(LispExpr::Number(LispNumber::Integer(app.height() as i64)));
+    });
+
+    primitive!(env, Arity::Exact(3), "set-pixel!", |args, app| {
+        if type_match!(
+            args, 0 => LispExpr::Number(LispNumber::Integer(_)),
+            1 => LispExpr::Number(LispNumber::Integer(_)),
+            2 => LispExpr::BoolLit(_)
+        ) {
+            let x = args[0].unwrap_number();
+            let y = args[1].unwrap_number();
+            let val = args[2].cast_bool();
+
+            let set_loc: MapPoint = (x.unwrap_integer(), y.unwrap_integer())
+                .try_into()
+                .map_err(|_| -> LispError { EvalError::InvalidCoordinates((x, y)).into() })?;
+            if !app.pixmap.contains(set_loc) {
+                return Err(EvalError::InvalidCoordinates((x, y)).into());
+            } else {
+                let old_val = app.pixmap.set(set_loc, val);
+                app.current_operation
+                    .push(PaintRecord::new(set_loc, old_val, val));
+                return Ok(LispExpr::Unit);
+            }
+        } else {
+            return Err(EvalError::TypeMismatch.into());
+        }
+    });
+
+    primitive!(env, Arity::Exact(0), "commit", |_, app| {
+        app.commit_operation();
+        return Ok(LispExpr::Unit);
+    });
+
     Ok(env)
 }
diff --git a/src/lisp/std.lisp b/src/lisp/std.lisp
index d54b32c..97c3984 100644
--- a/src/lisp/std.lisp
+++ b/src/lisp/std.lisp
@@ -45,3 +45,9 @@
 
 (define (sum ls) (fold 0 + ls))
 (define (product ls) (fold 1 * ls))
+
+(define (enumerate start stop step)
+  (if (> start stop)
+      '()
+      (cons start
+            (enumerate (+ start step) stop step))))