Structure StringCvt
(* StringCvt -- SML Basis Library *)
datatype radix = BIN | OCT | DEC | HEX
datatype realfmt =
SCI of int option (* scientific, arg = # dec. digits, dflt=6 *)
| FIX of int option (* fixed-point, arg = # dec. digits, dflt=6 *)
| GEN of int option (* auto choice of the above, *)
(* arg = # significant digits, dflt=12 *)
type cs (* character source state *)
type ('a, 'b) reader = 'b -> ('a * 'b) option
val scanString : ((char, cs) reader -> ('a, cs) reader) -> string -> 'a option
val splitl : (char -> bool) -> (char, 'a) reader -> 'a -> string * 'a
val takel : (char -> bool) -> (char, 'a) reader -> 'a -> string
val dropl : (char -> bool) -> (char, 'a) reader -> 'a -> 'a
val skipWS : (char, 'a) reader -> 'a -> 'a
val padLeft : char -> int -> string -> string
val padRight : char -> int -> string -> string
(*
This structure presents tools for scanning strings and values from
functional character streams, and for simple formatting.
[('elm, 'src) reader] is the type of source readers for reading a
sequence of 'elm values from a source of type 'src. For instance,
a character source reader
getc : (char, cs) reader
is used for obtaining characters from a functional character source
src of type cs, one at a time. It should hold that
getc src = SOME(c, src') if the next character in src
is c, and src' is the rest of src;
= NONE if src contains no characters
A character source scanner takes a character source reader getc as
argument and uses it to scan a data value from the character
source.
[scanString scan s] turns the string s into a character source and
applies the scanner `scan' to that source.
[splitl p getc src] returns (pref, suff) where pref is the
longest prefix (left substring) of src all of whose characters
satisfy p, and suff is the remainder of src. That is, the first
character retrievable from suff, if any, is the leftmost character
not satisfying p. Does not skip leading whitespace.
[takel p getc src] returns the longest prefix (left substring) of
src all of whose characters satisfy predicate p. That is, if the
left-most character does not satisfy p, the result is the empty
string. Does not skip leading whitespace. It holds that
takel p getc src = #1 (splitl p getc src)
[dropl p getc src] drops the longest prefix (left substring) of
src all of whose characters satisfy predicate p. If all characters
do, it returns the empty source. It holds that
dropl p getc src = #2 (splitl p getc src)
[skipWS getc src] drops any leading whitespace from src.
Equivalent to dropl Char.isSpace.
[padLeft c n s] returns the string s if size s >= n, otherwise pads
s with (n - size s) copies of the character c on the left.
In other words, right-justifies s in a field n characters wide.
[padRight c n s] returns the string s if size s >= n, otherwise pads
s with (n - size s) copies of the character c on the right.
In other words, left-justifies s in a field n characters wide.
*)
Moscow ML 2.00