x.nim
@@ -0,0 +1,9 @@
+const
+ alphanumerics = "0123456789_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+proc alpha(n: char) bool = # Invalid indentation here.
+ if n in alphanumerics:
+ return true
+ else:
+ return false
+
+echo alpha(n)
\ No newline at end of file