Full functionality.

lisp.py

@@ -132,6 +132,13 @@ class Lisp:
 				else:
 					raise ValueError("Undefined variable: " + str(arguments[0]))
 				return arguments[0]
+			case "MAPCAR":
+				if len(arguments) != 3:
+					raise ValueError("Expected 3 arguments")
+				result = []
+				for i in range(0, min(len(arguments[1]), len(arguments[2]))):
+					result.append(self.evaluate([arguments[0], arguments[1][i], arguments[2][i]]))
+				return result
 			case _:
 				if operation in self.env.keys():
 					if type(self.env[operation]) == Function:

repl.py

@@ -2,7 +2,8 @@ import reader
 import sys
 
 def main():
-	print("Welcome message.")
+	print("Welcome to the lisp interpreter! REPL expression results will be stored in an output file, output.txt by default. This can be overridden by passing an argument to the program.\n"
+		  "Enter (quit) to exit the program. Supported functionality includes mathematical operations, conditional statements, variables, user-defined functions, logical operations, and list manipulation.")
 	outputfile = "output.txt" if len(sys.argv) == 1 else sys.argv[1]
 	interpreter = reader.Reader(outputfile)
 	# REPL Loop