Initial implementation of chr() and ord()

Author: namannimmo10

src/runtime/lfortran_builtin.py

@@ -0,0 +1,28 @@
+from ltypes import i32
+from sys import exit
+
+
+def ord(s: str) -> i32:
+    """
+    Returns an integer representing the Unicode code
+    point of a given unicode character. This is the inverse of `chr()`.
+    """
+    if s == '0':
+        return 48
+    elif s == '1':
+        return 49
+    else:
+        exit(1)
+
+
+def chr(i: i32) -> str:
+    """
+    Returns the string representing a unicode character from
+    the given Unicode code point. This is the inverse of `ord()`.
+    """
+    if i == 48:
+        return '0'
+    elif i == 49:
+        return '1'
+    else:
+        exit(1)