(* Title: Pure/basis.ML
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1993 University of Cambridge
Basis Library emulation.
Needed for Poly/ML and Standard ML of New Jersey version 0.93 to 1.08.
Full compatibility cannot be obtained using a file: what about char constants?
*)
exception Subscript;
structure Bool =
struct
fun toString true = "true"
| toString false = "false"
end;
structure Int =
struct
fun toString (i: int) = makestring i;
fun max (x, y) = if x < y then y else x : int;
fun min (x, y) = if x < y then x else y : int;
end;
structure List =
struct
exception Empty
fun last [] = raise Empty
| last [x] = x
| last (x::xs) = last xs;
fun nth (xs, n) =
let fun h [] _ = raise Subscript
| h (x::xs) n = if n=0 then x else h xs (n-1)
in if n<0 then raise Subscript else h xs n end;
fun drop (xs, n) =
let fun h xs 0 = xs
| h [] n = raise Subscript
| h (x::xs) n = h xs (n-1)
in if n<0 then raise Subscript else h xs n end;
fun take (xs, n) =
let fun h xs 0 = []
| h [] n = raise Subscript
| h (x::xs) n = x :: h xs (n-1)
in if n<0 then raise Subscript else h xs n end;
fun concat [] = []
| concat (l::ls) = l @ concat ls;
end;
structure ListPair =
struct
fun zip ([], []) = []
| zip (x::xs,y::ys) = (x,y) :: zip(xs,ys);
fun unzip [] = ([],[])
| unzip((x,y)::pairs) =
let val (xs,ys) = unzip pairs
in (x::xs, y::ys) end;
fun map f ([], []) = []
| map f (x::xs,y::ys) = f(x,y) :: map f (xs,ys);
fun exists pred =
let fun boolf ([], []) = false
| boolf (x::xs,y::ys) = pred(x,y) orelse boolf (xs,ys)
in boolf end;
fun all pred =
let fun boolf ([], []) = true
| boolf (x::xs,y::ys) = pred(x,y) andalso boolf (xs,ys)
in boolf end;
end;
structure TextIO =
struct
type instream = instream
and outstream = outstream
exception Io of {name: string, function: string, cause: exn}
val stdIn = std_in
val stdOut = std_out
val openIn = open_in
val openAppend = open_append
val openOut = open_out
val closeIn = close_in
val closeOut = close_out
val inputN = input
val inputAll = fn is => inputN (is, 999999)
val inputLine = input_line
val endOfStream = end_of_stream
val output = output
val flushOut = flush_out
end;
fun print s = (output (std_out, s); flush_out std_out);