The Bool
structure
The Bool structure provides some basic operations on boolean values.
Synopsis
signature BOOL
structure Bool
: BOOL
Interface
datatype bool = datatype bool
val not : bool -> bool
val fromString : string -> bool option
val scan : (char, 'a) StringCvt.reader -> 'a -> (bool * 'a) option
val toString : bool -> string
Description
-
datatype bool
-
-
not b
-
returns the logical negation of the boolean value b.
-
fromString s
scan getc strm
-
scan a boolean value from a stream of characters. Ignoring case and initial whitespace, the sequences
"true"
and"false"
are converted to the corresponding boolean values, respectively.The function
fromString
takes a string s as its source of characters. It returnsSOME b
for a scanned value b; otherwise it returns NONE. Note that the functionfromString
is equivalent toStringCvt.scanString scan
.The function
scan
takes a character stream reader getc and a stream strm. On successful scanning of a boolean value, it returnsSOME(b, strm')
, where b is the scanned value and strm' is the remaining character stream. The type of scan can also be written as(char, 'a) StringCvt.reader -> (bool, 'a) StringCvt.reader
.
-
toString b
-
returns the string representation, which is either
"true"
or"false"
, of the boolean value b.
See Also
StringCvt