shuffle around parser elements

lib/parsers.ml

@@ -0,0 +1,9 @@
+open Angstrom
+
+let is_digit = function '0' .. '9' -> true | _ -> false
+let is_semi c = c == ';'
+
+let digit = take_while is_digit >>| int_of_string
+let skip_semi = skip is_semi
+
+let semi_digits = sep_by1 skip_semi digit