add new brush type

4 files changed, 24 insertions, 1 deletions

diff --git a/src/lisp/error.rs b/src/lisp/error.rs
index b90e211..a360eb2 100644
--- a/src/lisp/error.rs
+++ b/src/lisp/error.rs
@@ -90,6 +90,7 @@ pub enum EvalError {
     DivByZero,
     TypeMismatch,
     NoFileName,
+    CustomInternal(&'static str),
 }
 
 impl fmt::Display for EvalError {
@@ -112,6 +113,7 @@ impl fmt::Display for EvalError {
             Self::TypeMismatch => write!(f, "mismatched types"),
             Self::DivByZero => write!(f, "attempt to divide by zero"),
             Self::NoFileName => write!(f, "no file name specified"),
+            Self::CustomInternal(s) => write!(f, "{}", s),
         }
     }
 }
diff --git a/src/lisp/eval.rs b/src/lisp/eval.rs
index 370b624..6ffff23 100644
--- a/src/lisp/eval.rs
+++ b/src/lisp/eval.rs
@@ -20,6 +20,7 @@ pub fn eval(expr: &LispExpr, app: &mut AppState) -> Result<LispExpr, LispError>
         LispExpr::Number(_) => Ok(expr.clone()),
         LispExpr::BoolLit(_) => Ok(expr.clone()),
         LispExpr::Ident(ref id) => lookup_extended(&app.lisp_env, id),
+        LispExpr::Quote(_, _) => Ok(expr.clone()),
         LispExpr::List(li) => {
             let func_expr = &li[0];
             match func_expr {
diff --git a/src/lisp/expr.rs b/src/lisp/expr.rs
index 40420a1..9ef9f65 100644
--- a/src/lisp/expr.rs
+++ b/src/lisp/expr.rs
@@ -222,6 +222,7 @@ impl AsRef<str> for LispExpr {
     fn as_ref(&self) -> &str {
         match self {
             LispExpr::StringLit(i) => &i,
+            LispExpr::Ident(i) => &i,
             _ => panic!("invalid downcast!"),
         }
     }
diff --git a/src/lisp/prelude.rs b/src/lisp/prelude.rs
index 6153e4f..d2a6ae6 100644
--- a/src/lisp/prelude.rs
+++ b/src/lisp/prelude.rs
@@ -1,7 +1,8 @@
 use crate::{
+    brush::Brush,
     lisp::{
         error::{EvalError, LispError},
-        expr::{Arity, LispExpr},
+        expr::{is_ident, Arity, LispExpr},
         number::LispNumber,
         Environment,
     },
@@ -193,5 +194,23 @@ pub fn new_env() -> Environment {
         return Ok(LispExpr::Unit);
     });
 
+    primitive!(env, Arity::Atmost(1), "brush", |args, app| {
+        info!("brush {}", &args[0]);
+        if let [LispExpr::Quote(kind, _)] = args {
+            if is_ident(kind) {
+                match (&**kind).as_ref() {
+                    "fill" => app.brush = Brush::Fill,
+                    "circle" => app.brush = Brush::new(),
+                    "line" => app.brush = Brush::line(0, false),
+                    "line-extend" => app.brush = Brush::line(0, true),
+                    _ => return Err(EvalError::CustomInternal("unknown brush type").into()),
+                }
+            }
+        } else {
+            return Err(EvalError::TypeMismatch.into());
+        }
+        return Ok(LispExpr::Unit);
+    });
+
     env
 }