The SML/NJ Library is a collection of libraries that are distributed with SML/NJ. Due to differences between SML/NJ and MLton, these libraries will not work out-of-the box with MLton.

As of 20151110, MLton includes a port of the SML/NJ Library synchronized with SML/NJ version 110.78.

Usage

  • You can import a sub-library of the SML/NJ Library into an MLB file with:

    MLB file Description

    $(SML_LIB)/smlnj-lib/Util/smlnj-lib.mlb

    Various utility modules, included collections, simple formating, …

    $(SML_LIB)/smlnj-lib/Controls/controls-lib.mlb

    A library for managing control flags in an application.

    $(SML_LIB)/smlnj-lib/HashCons/hash-cons-lib.mlb

    Support for implementing hash-consed data structures.

    $(SML_LIB)/smlnj-lib/HTML/html-lib.mlb

    HTML 3.2 parsing and pretty-printing library.

    $(SML_LIB)/smlnj-lib/HTML4/html4-lib.mlb

    HTML 4.01 parsing and pretty-printing library.

    $(SML_LIB)/smlnj-lib/INet/inet-lib.mlb

    Networking utilities; supported on both Unix and Windows systems.

    $(SML_LIB)/smlnj-lib/JSON/json-lib.mlb

    JavaScript Object Notation (JSON) reading and writing library.

    $(SML_LIB)/smlnj-lib/PP/pp-lib.mlb

    Pretty-printing library.

    $(SML_LIB)/smlnj-lib/Reactive/reactive-lib.mlb

    Reactive scripting library.

    $(SML_LIB)/smlnj-lib/RegExp/regexp-lib.mlb

    Regular expression library.

    $(SML_LIB)/smlnj-lib/SExp/sexp-lib.mlb

    S-expression library.

    $(SML_LIB)/smlnj-lib/Unix/unix-lib.mlb

    Utilities for Unix-based operating systems.

    $(SML_LIB)/smlnj-lib/XML/xml-lib.mlb

    XML library.

  • If you are porting a project from SML/NJ’s CompilationManager to MLton’s ML Basis system using cm2mlb, note that the following maps are included by default:

    # SMLNJ Library
    $SMLNJ-LIB                              $(SML_LIB)/smlnj-lib
    $smlnj-lib.cm                           $(SML_LIB)/smlnj-lib/Util
    $controls-lib.cm                        $(SML_LIB)/smlnj-lib/Controls
    $hash-cons-lib.cm                       $(SML_LIB)/smlnj-lib/HashCons
    $html-lib.cm                            $(SML_LIB)/smlnj-lib/HTML
    $html4-lib.cm                           $(SML_LIB)/smlnj-lib/HTML4
    $inet-lib.cm                            $(SML_LIB)/smlnj-lib/INet
    $json-lib.cm                            $(SML_LIB)/smlnj-lib/JSON
    $pp-lib.cm                              $(SML_LIB)/smlnj-lib/PP
    $reactive-lib.cm                        $(SML_LIB)/smlnj-lib/Reactive
    $regexp-lib.cm                          $(SML_LIB)/smlnj-lib/RegExp
    $sexp-lib.cm                            $(SML_LIB)/smlnj-lib/SExp
    $unix-lib.cm                            $(SML_LIB)/smlnj-lib/Unix
    $xml-lib.cm                             $(SML_LIB)/smlnj-lib/XML

    This will automatically convert a $/smlnj-lib.cm import in an input .cm file into a $(SML_LIB)/smlnj-lib/Util/smlnj-lib.mlb import in the output .mlb file.

Details

The following changes were made to the SML/NJ Library, in addition to deriving the .mlb files from the .cm files:

  • HTML4/pp-init.sml (added): Implements structure PrettyPrint using the SML/NJ PP Library. This implementation is taken from the SML/NJ compiler source, since the SML/NJ HTML4 Library used the structure PrettyPrint provided by the SML/NJ compiler itself.

  • Util/base64.sml (modified): Rewrote use of Unsafe.CharVector.create and Unsafe.CharVector.update; MLton assumes that vectors are immutable.

  • Util/bit-array.sml (modified): The computation of the maxLen is given by:

    val maxLen = 8*Word8Array.maxLen
    

    This is fine in SML/NJ where Word8Array.maxLen is 16777215, but in MLton, Word8Array.maxLen is equal to valOf(Int.maxInt), so the computation overflows. To accommodate both SML/NJ and MLton, the computation is replaced by

    val maxLen = (8*Word8Array.maxLen) handle Overflow => Word8Array.maxLen
    
  • Util/engine.mlton.sml (added, not exported): Implements structure Engine, providing time-limited, resumable computations using MLtonThread, MLtonSignal, and MLtonItimer.

  • Util/graph-scc-fn.sml (modified): Rewrote use of where structure specification.

  • Util/redblack-map-fn.sml (modified): Rewrote use of where structure specification.

  • Util/redblack-set-fn.sml (modified): Rewrote use of where structure specification.

  • Util/time-limit.mlb (added): Exports structure TimeLimit, which is not exported by smlnj-lib.mlb. Since MLton is very conservative in the presence of threads and signals, program performance may be adversely affected by unnecessarily including structure TimeLimit.

  • Util/time-limit.mlton.sml (added): Implements structure TimeLimit using structure Engine. The SML/NJ implementation of structure TimeLimit uses SML/NJ’s first-class continuations, signals, and interval timer.

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