smlnj - SML splitting string on first space -

as of right reading in entire input file using inputall , using string.tokens split each word @ every occurrence of space.

val file = textio.openin input val _input = textio.inputall file val _ = textio.closein file string.tokens char.isspace _input 

ex) "red blue green" this

["red", "blue", "green"] 

however, change split string @ first occurrence of space char on each line.

ex) "red blue green" should like

["red", "blue green"] 

i have feeling need utilize other inputall accomplish this, , main question how make splits @ first space of each line.

textio.inputall fine. in case seems string.tokens not right tool job. write own function, using string.explode , string.implode convert string to/from char list.

fun splitcharsfirstspace cs =   case cs of     [] => ([], [])   | c :: cs' =>       if char.isspace c ([], cs')       else let val (l, r) = splitcharsfirstspace cs'            in (c :: l, r)            end  fun splitfirstspace s =   let     val (l, r) = splitcharsfirstspace (string.explode s)   in     (string.implode l, string.implode r)   end 

in context, use follows.

val file = textio.openin input val contents = textio.inputall file val _ = textio.closein file val lines = string.tokens (fn c => c = #"\n") contents val lines' = list.map splitfirstspace lines 

for example, if input file this:

red blue green yellow orange purple pink 

then lines' this:

[("red", "blue green"), ("yellow", "orange purple pink")]