3 files changed, 43 insertions, 5 deletions

diff --git a/src/lisp/error.rs b/src/lisp/error.rs
index 9e9dc90..7bde872 100644
--- a/src/lisp/error.rs
+++ b/src/lisp/error.rs
@@ -1,7 +1,10 @@
-use crate::lisp::{
-    expr::{Arity, LispExpr},
-    lex::{Span, SpanDisplay},
-    number::LispNumber,
+use crate::{
+    keybind::KeybindError,
+    lisp::{
+        expr::{Arity, LispExpr},
+        lex::{Span, SpanDisplay},
+        number::LispNumber,
+    },
 };
 
 use std::{fmt, io};
@@ -104,6 +107,7 @@ pub enum EvalError {
     AssertionError { expected: LispExpr, got: LispExpr },
     ScriptLoadError(io::Error),
     CustomInternal(&'static str),
+    KeybindError(KeybindError),
     Custom(String),
 }
 
@@ -134,6 +138,7 @@ impl fmt::Display for EvalError {
                 write!(f, "assertion error: expected `{}` got `{}`", expected, got)
             }
             Self::ScriptLoadError(s) => write!(f, "error while loading script: {}", s),
+            Self::KeybindError(k) => write!(f, "keybind error: {}", k),
             Self::CustomInternal(s) => write!(f, "{}", s),
             Self::Custom(s) => write!(f, "error: {}", s),
         }
diff --git a/src/lisp/eval.rs b/src/lisp/eval.rs
index 75cb5c9..677fa23 100644
--- a/src/lisp/eval.rs
+++ b/src/lisp/eval.rs
@@ -1,5 +1,6 @@
 use crate::{
     app::AppState,
+    keybind::Keybind,
     lisp::{
         error::{EvalError, LispError},
         expr::{Arity, Ident, LispExpr, LispFunction},
@@ -8,7 +9,7 @@ use crate::{
     type_match,
 };
 
-use std::convert::TryInto;
+use std::{convert::TryInto, str::FromStr};
 
 use log::{error, info};
 
@@ -44,6 +45,7 @@ where
                         "for" => self.eval_for(&li[1..]),
                         "quote" => Ok(apply_quote(&li[1])),
                         "let" => self.eval_let(&li[1..]),
+                        "bind-key" => self.eval_bind_key(&li[1..]),
                         _ => {
                             let mut new_ls = vec![self.eval(&func_expr)?];
                             new_ls.extend(li[1..].to_vec());
@@ -302,6 +304,22 @@ where
             }
         }
     }
+
+    pub fn eval_bind_key(&mut self, args: &[LispExpr]) -> Result<LispExpr, LispError> {
+        let arity = Arity::Exact(2);
+        if !arity.check(args) {
+            Err(arity.to_error())
+        } else {
+            match args {
+                [LispExpr::StringLit(s), body] => {
+                    let bind = Keybind::from_str(&s).map_err(EvalError::KeybindError)?;
+                    self.app.keybinds.insert(bind, body.clone());
+                    Ok(LispExpr::Unit)
+                }
+                _ => Err(EvalError::BadForm.into()),
+            }
+        }
+    }
 }
 
 pub fn apply_quote(arg: &LispExpr) -> LispExpr {
diff --git a/src/lisp/std.lisp b/src/lisp/std.lisp
index a256125..fe09a8a 100644
--- a/src/lisp/std.lisp
+++ b/src/lisp/std.lisp
@@ -72,3 +72,18 @@
           acc
           (rev-helper (cdr p) (cons (car p) acc))))
     (rev-helper ls '())))
+
+(define (append l1 l2)
+  (if (null? l1)
+      l2
+      (cons (car l1)
+            (append (cdr l1) l2))))
+
+(define (cross xs ys)
+  (if (or (null? xs)
+          (null? ys))
+      '()
+      (fold '()
+            append
+            (map (lambda (x)
+                   (map (lambda (y) (list x y)) ys)) xs))))