Basis Library

9 Basis Library

This section describes MLton's implementation of the Standard ML Basis Library, which by default MLton makes available to user programs. The latest version of the Basis Library specification is at http://www.standardml.org/Basis/. For a reverse chronological list of changes to the specification, see http://www.standardml.org/Basis/history.html. Since the specification does change, we place a snapshot at http://www.mlton.org/basis/ at the time of each MLton public release. You can also obtain a complete and current list of what's available by using mlton -show-basis.

In summary, MLton implements all of the required portions of the Basis Library. MLton also implements many of the optional structures, as seen below.

9.1 Top-level types and constructors

eqtype 'a array datatype bool = false | true eqtype char type exn eqtype int datatype 'a list = nil | :: of ('a * 'a list) datatype 'a option = NONE | SOME of 'a datatype order = EQUAL | GREATER | LESS type real datatype 'a ref = ref of 'a eqtype string type substring eqtype unit eqtype 'a vector eqtype word

9.2 Top-level exception constructors

Bind, Chr, Div, Domain, Empty, Fail, Match, Option, Overflow, Size, Span, Subscript.

9.3 Top-level values

MLton does not implement the optional top-level value use: string -> unit, which conflicts with whole-program compilation because it allows new code to be loaded dynamically. MLton implements all other top-level values:

!, :=, <>, =, @, ^, app, before, ceil, chr, concat, exnMessage, exnName, explode, floor, foldl, foldr, getOpt, hd, ignore, implode, isSome, length, map, not, null, o, ord, print, real, rev, round, size, str, substring, tl, trunc, valOf, vector.

9.4 Overloaded identifiers

*, +, -, /, <, <=, >, >=, ~, abs, div, mod.

9.5 Top-level signatures

ARRAY
ARRAY2
ARRAY_SLICE
BIN_IO
BIT_FLAGS
BOOL
BYTE
CHAR
COMMAND_LINE
DATE
GENERAL
GENERIC_SOCK
IEEE_REAL
IMPERATIVE_IO
INET_SOCK
INTEGER
INT_INF
IO
LIST
LIST_PAIR
MATH
MONO_ARRAY
MONO_ARRAY2
MONO_ARRAY_SLICE
MONO_VECTOR
MONO_VECTOR_SLICE
NET_HOST_DB
NET_PROT_DB
NET_SERV_DB
OPTION
OS
OS_FILE_SYS
OS_IO
OS_PATH
OS_PROCESS
PACK_REAL
PACK_WORD
POSIX
POSIX_ERROR
POSIX_FILE_SYS
POSIX_IO
POSIX_PROCESS
POSIX_PROC_ENV
POSIX_SIGNAL
POSIX_SYS_DB
POSIX_TTY
PRIM_IO
REAL
SOCKET
STREAM_IO
STRING
STRING_CVT
SUBSTRING
TEXT
TEXT_IO
TEXT_STREAM_IO
TIME
TIMER
UNIX
UNIX_SOCK
VECTOR
VECTOR_SLICE
WORD.

9.6 Top-level structures

Array: ARRAY
Array2: ARRAY2
ArraySlice: ARRAY_SLICE
BinIO: BIN_IO
BinPrimIO: PRIM_IO
Bool: BOOL
BoolArray: MONO_ARRAY
BoolArray2: MONO_ARRAY2
BoolArraySlice: MONO_ARRAY_SLICE
BoolVector: MONO_VECTOR
BoolVectorSlice: MONO_VECTOR_SLICE
Byte: BYTE
Char: CHAR
CharArray: MONO_ARRAY
CharArray2: MONO_ARRAY2
CharArraySlice: MONO_ARRAY_SLICE
CharVector: MONO_VECTOR
CharVectorSlice: MONO_VECTOR_SLICE
CommandLine: COMMAND_LINE
Date: DATE

Date.fromString and Date.scan accept a space in addition to a zero for the first character of the day of the month. The basis library specification only allows a zero.

FixedInt: INTEGER
General: GENERAL
GenericSock: GENERIC_SOCK
IEEEReal: IEEE_REAL
INetSock: INET_SOCK
IO: IO
Int: INTEGER
Int2: INTEGER
Int3: INTEGER
Int4: INTEGER
...
Int31: INTEGER
Int32: INTEGER
Int64: INTEGER
IntArray: MONO_ARRAY
IntArray2: MONO_ARRAY2
IntArraySlice: MONO_ARRAY_SLICE
IntVector: MONO_VECTOR
IntVectorSlice: MONO_VECTOR_SLICE
Int8: INTEGER
Int8Array: MONO_ARRAY
Int8Array2: MONO_ARRAY2
Int8ArraySlice: MONO_ARRAY_SLICE
Int8Vector: MONO_VECTOR
Int8VectorSlice: MONO_VECTOR_SLICE
Int16: INTEGER
Int16Array: MONO_ARRAY
Int16Array2: MONO_ARRAY2
Int16ArraySlice: MONO_ARRAY_SLICE
Int16Vector: MONO_VECTOR
Int16VectorSlice: MONO_VECTOR_SLICE
Int32: INTEGER
Int32Array: MONO_ARRAY
Int32Array2: MONO_ARRAY2
Int32ArraySlice: MONO_ARRAY_SLICE
Int32Vector: MONO_VECTOR
Int32VectorSlice: MONO_VECTOR_SLICE
Int64Array: MONO_ARRAY
Int64Array2: MONO_ARRAY2
Int64ArraySlice: MONO_ARRAY_SLICE
Int64Vector: MONO_VECTOR
Int64VectorSlice: MONO_VECTOR_SLICE
IntInf: INT_INF
LargeInt: INTEGER
LargeIntArray: MONO_ARRAY
LargeIntArray2: MONO_ARRAY2
LargeIntArraySlice: MONO_ARRAY_SLICE
LargeIntVector: MONO_VECTOR
LargeIntVectorSlice: MONO_VECTOR_SLICE
LargeReal: REAL
LargeRealArray: MONO_ARRAY
LargeRealArray2: MONO_ARRAY2
LargeRealArraySlice: MONO_ARRAY_SLICE
LargeRealVector: MONO_VECTOR
LargeRealVectorSlice: MONO_VECTOR_SLICE
LargeWord: WORD
LargeWordArray: MONO_ARRAY
LargeWordArray2: MONO_ARRAY2
LargeWordArraySlice: MONO_ARRAY_SLICE
LargeWordVector: MONO_VECTOR
LargeWordVectorSlice: MONO_VECTOR_SLICE
List: LIST
ListPair: LIST_PAIR
Math: MATH
NetHostDB: NET_HOST_DB
NetProtDB: NET_PROT_DB
NetServDB: NET_SERV_DB
OS: OS
Option: OPTION
PackReal32Big: PACK_REAL
PackReal32Little: PACK_REAL
PackReal64Big: PACK_REAL
PackReal64Little: PACK_REAL
PackRealBig: PACK_REAL
PackRealLittle: PACK_REAL
PackWord32Big: PACK_WORD
PackWord32Little: PACK_WORD
Position: INTEGER
Posix: POSIX
Real: REAL
RealArray: MONO_ARRAY
RealArray2: MONO_ARRAY2
RealArraySlice: MONO_ARRAY_SLICE
RealVector: MONO_VECTOR
RealVectorSlice: MONO_VECTOR_SLICE
Real32: REAL
Real32Array: MONO_ARRAY
Real32Array2: MONO_ARRAY2
Real32ArraySlice: MONO_ARRAY_SLICE
Real32Vector: MONO_VECTOR
Real32VectorSlice: MONO_VECTOR_SLICE
Real64: REAL
Real64Array: MONO_ARRAY
Real64Array2: MONO_ARRAY2
Real64ArraySlice: MONO_ARRAY_SLICE
Real64Vector: MONO_VECTOR
Real64VectorSlice: MONO_VECTOR_SLICE
Socket: SOCKET
String: STRING
StringCvt: STRING_CVT
Substring: SUBSTRING
SysWord: WORD
Text: TEXT
TextIO: TEXT_IO
TextPrimIO: PRIM_IO
Time: TIME
Timer: TIMER
Unix: UNIX
UnixSock: UNIX_SOCK
Vector: VECTOR
VectorSlice: VECTOR_SLICE
Word: WORD
Word2: WORD
Word3: WORD
Word4: WORD
...
Word31: WORD
Word32: WORD
Word64: WORD
WordArray: MONO_ARRAY
WordArray2: MONO_ARRAY2
WordArraySlice: MONO_ARRAY_SLICE
WordVectorSlice: MONO_VECTOR_SLICE
WordVector: MONO_VECTOR
Word8Array: MONO_ARRAY
Word8Array2: MONO_ARRAY2
Word8ArraySlice: MONO_ARRAY_SLICE
Word8Vector: MONO_VECTOR
Word8VectorSlice: MONO_VECTOR_SLICE
Word16Array: MONO_ARRAY
Word16Array2: MONO_ARRAY2
Word16ArraySlice: MONO_ARRAY_SLICE
Word16Vector: MONO_VECTOR
Word16VectorSlice: MONO_VECTOR_SLICE
Word32Array: MONO_ARRAY
Word32Array2: MONO_ARRAY2
Word32ArraySlice: MONO_ARRAY_SLICE
Word32Vector: MONO_VECTOR
Word32VectorSlice: MONO_VECTOR_SLICE
Word64Array: MONO_ARRAY
Word64Array2: MONO_ARRAY2
Word64ArraySlice: MONO_ARRAY_SLICE
Word64Vector: MONO_VECTOR
Word64VectorSlice: MONO_VECTOR_SLICE

The following types are equivalent.

Int.int = Int32.int

Int64.int = FixedInt.int = Position.int

IntInf.int = LargeInt.int

Real.real = Real64.real = LargeReal.real

Word.word = Word32.word = SysWord.word

Word64.word = LargeWord.word

The Real, Real32, and Real64 modules are implemented using the C math library, so the SML functions will reflect the behavior of the underlying library function. We have made some effort to unify the differences between the math libraries on different platforms, and in particular to handle exceptional cases according to the basis library specification. However, there will be differences due to different numerical algorithms and cases we may have missed. Please submit a bug report if you encounter an error in the handling of an exceptional case.

On x86, real arithmetic is implemented internally using 80 bits of precision. Using higher precision for intermediate results in computations can lead to different results than if all the computation is done at 32 or 64 bits. If you require strict IEEE compliance, you can compile with -ieee-fp true, which will cause intermediate results to be stored after each operation. This may cause a substantial performance penalty.

9.7 Top-level functors

ImperativeIO
PrimIO
StreamIO

MLton's StreamIO functor takes structures ArraySlice and VectorSlice in addition to the arguments specified in the basis library documentation.