implement read-char

1 files changed, 14 insertions, 0 deletions

diff --git a/interpreter.py b/interpreter.py
index a2d7b08..e2cf006 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -712,6 +712,20 @@ def interpretReadLine(symbol, args, env):
 
 GLOBALS.register("read-line", Builtin(interpretReadLine, [Arg("prompt", T.String, False, False)]))
 
+def interpretReadChar(symbol, args, env):
+    import termios, tty
+    fd = sys.stdin.fileno()
+    old = termios.tcgetattr(fd)
+    try:
+        tty.setraw(fd)
+        ch = sys.stdin.buffer.read1(4)  # some keys are >1 bytes
+    except Exception:
+        raise
+    finally:
+        termios.tcsetattr(fd, termios.TCSADRAIN, old)
+    return String(ch.decode("utf-8"))
+
+GLOBALS.register("read-char", Builtin(interpretReadChar, []))
 
 def interpretAppend(symbol, args, env):
     lst = args[0]