Question

I’m trying to read text from a file in SML. Eventually, I want a list of individual words; however, I’m struggling at how to convert between a TextIO.elem to a string. For example, if I write the following code it returns a TextIO.elem but I don’t know how to convert it to a string so that I can concat it with another string

TextIO.input1 inStream

Answer 1

TextIO.elem is just a synonym for char, so you can use the str function to convert it to a string. But as I replied to elsewhere, I suggest using TextIO.inputAll to get a string right away.

Here is a function that takes an instream and delivers all (remaining) words in it:

val words = String.tokens Char.isSpace o TextIO.inputAll

The type of this function is TextIO.instream -> string list.