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The <tt>MLton</tt> structure contains a lot of functionality that is not available in the <a href="BasisLibrary">Basis Library</a>. As a warning, please keep in mind that the <tt>MLton</tt> structure and its substructures do change from release to release of MLton.
<pre class=code>
<B><FONT COLOR="#0000FF">structure</FONT></B> MLton:
<B><FONT COLOR="#0000FF">sig</FONT></B>
<B><FONT COLOR="#A020F0">val</FONT></B> eq: 'a * 'a -> bool
<B><FONT COLOR="#A020F0">val</FONT></B> equal: 'a * 'a -> bool
<B><FONT COLOR="#A020F0">val</FONT></B> hash: 'a -> Word32.word
<B><FONT COLOR="#A020F0">val</FONT></B> isMLton: bool
<B><FONT COLOR="#A020F0">val</FONT></B> share: 'a -> unit
<B><FONT COLOR="#A020F0">val</FONT></B> shareAll: unit -> unit
<B><FONT COLOR="#A020F0">val</FONT></B> size: 'a -> int
<B><FONT COLOR="#0000FF">structure</FONT></B> Array: MLTON_ARRAY
<B><FONT COLOR="#0000FF">structure</FONT></B> BinIO: MLTON_BIN_IO
<B><FONT COLOR="#0000FF">structure</FONT></B> CharArray: MLTON_MONO_ARRAY <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> CharArray.array
</FONT></B><B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> elem </FONT></B>=<B><FONT COLOR="#228B22"> CharArray.elem
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> CharVector: MLTON_MONO_VECTOR <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> CharVector.vector
</FONT></B><B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> elem </FONT></B>=<B><FONT COLOR="#228B22"> CharVector.elem
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Cont: MLTON_CONT
<B><FONT COLOR="#0000FF">structure</FONT></B> Exn: MLTON_EXN
<B><FONT COLOR="#0000FF">structure</FONT></B> Finalizable: MLTON_FINALIZABLE
<B><FONT COLOR="#0000FF">structure</FONT></B> GC: MLTON_GC
<B><FONT COLOR="#0000FF">structure</FONT></B> IntInf: MLTON_INT_INF
<B><FONT COLOR="#0000FF">structure</FONT></B> Itimer: MLTON_ITIMER
<B><FONT COLOR="#0000FF">structure</FONT></B> LargeReal: MLTON_REAL <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> LargeReal.real
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> LargeWord: MLTON_WORD <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> LargeWord.word
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Platform: MLTON_PLATFORM
<B><FONT COLOR="#0000FF">structure</FONT></B> Pointer: MLTON_POINTER
<B><FONT COLOR="#0000FF">structure</FONT></B> ProcEnv: MLTON_PROC_ENV
<B><FONT COLOR="#0000FF">structure</FONT></B> Process: MLTON_PROCESS
<B><FONT COLOR="#0000FF">structure</FONT></B> Profile: MLTON_PROFILE
<B><FONT COLOR="#0000FF">structure</FONT></B> Random: MLTON_RANDOM
<B><FONT COLOR="#0000FF">structure</FONT></B> Real: MLTON_REAL <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Real.real
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Real32: <B><FONT COLOR="#0000FF">sig</FONT></B>
<B><FONT COLOR="#0000FF">include</FONT></B> MLTON_REAL
<B><FONT COLOR="#A020F0">val</FONT></B> castFromWord: Word32.word -> t
<B><FONT COLOR="#A020F0">val</FONT></B> castToWord: t -> Word32.word
<B><FONT COLOR="#0000FF">end</FONT></B> <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Real32.real
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Real64: <B><FONT COLOR="#0000FF">sig</FONT></B>
<B><FONT COLOR="#0000FF">include</FONT></B> MLTON_REAL
<B><FONT COLOR="#A020F0">val</FONT></B> castFromWord: Word64.word -> t
<B><FONT COLOR="#A020F0">val</FONT></B> castToWord: t -> Word64.word
<B><FONT COLOR="#0000FF">end</FONT></B> <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Real64.real
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Rlimit: MLTON_RLIMIT
<B><FONT COLOR="#0000FF">structure</FONT></B> Rusage: MLTON_RUSAGE
<B><FONT COLOR="#0000FF">structure</FONT></B> Signal: MLTON_SIGNAL
<B><FONT COLOR="#0000FF">structure</FONT></B> Socket: MLTON_SOCKET
<B><FONT COLOR="#0000FF">structure</FONT></B> Syslog: MLTON_SYSLOG
<B><FONT COLOR="#0000FF">structure</FONT></B> TextIO: MLTON_TEXT_IO
<B><FONT COLOR="#0000FF">structure</FONT></B> Thread: MLTON_THREAD
<B><FONT COLOR="#0000FF">structure</FONT></B> Vector: MLTON_VECTOR
<B><FONT COLOR="#0000FF">structure</FONT></B> Weak: MLTON_WEAK
<B><FONT COLOR="#0000FF">structure</FONT></B> Word: MLTON_WORD <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word.word
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Word8: MLTON_WORD <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word8.word
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Word16: MLTON_WORD <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word16.word
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Word32: MLTON_WORD <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word32.word
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Word64: MLTON_WORD <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word64.word
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Word8Array: MLTON_MONO_ARRAY <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word8Array.array
</FONT></B><B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> elem </FONT></B>=<B><FONT COLOR="#228B22"> Word8Array.elem
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> Word8Vector: MLTON_MONO_VECTOR <B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> t </FONT></B>=<B><FONT COLOR="#228B22"> Word8Vector.vector
</FONT></B><B><FONT COLOR="#0000FF">where</FONT></B> <B><FONT COLOR="#0000FF">type</FONT></B><B><FONT COLOR="#228B22"> elem </FONT></B>=<B><FONT COLOR="#228B22"> Word8Vector.elem
</FONT></B><B><FONT COLOR="#0000FF">structure</FONT></B> World: MLTON_WORLD
<B><FONT COLOR="#0000FF">end</FONT></B>
</PRE>
<p>
</p>
<h2 id="head-58b7888b27adca6d197bc42df58e8c0c70fe97d0">Substructures</h2>
<ul>
<li>
<p>
<a href="MLtonArray">MLtonArray</a>
</p>
</li>
<li>
<p>
<a href="MLtonBinIO">MLtonBinIO</a>
</p>
</li>
<li>
<p>
<a href="MLtonCont">MLtonCont</a>
</p>
</li>
<li>
<p>
<a href="MLtonExn">MLtonExn</a>
</p>
</li>
<li>
<p>
<a href="MLtonFinalizable">MLtonFinalizable</a>
</p>
</li>
<li>
<p>
<a href="MLtonGC">MLtonGC</a>
</p>
</li>
<li>
<p>
<a href="MLtonIntInf">MLtonIntInf</a>
</p>
</li>
<li>
<p>
<a href="MLtonIO">MLtonIO</a>
</p>
</li>
<li>
<p>
<a href="MLtonItimer">MLtonItimer</a>
</p>
</li>
<li>
<p>
<a href="MLtonMonoArray">MLtonMonoArray</a>
</p>
</li>
<li>
<p>
<a href="MLtonMonoVector">MLtonMonoVector</a>
</p>
</li>
<li>
<p>
<a href="MLtonPlatform">MLtonPlatform</a>
</p>
</li>
<li>
<p>
<a href="MLtonPointer">MLtonPointer</a>
</p>
</li>
<li>
<p>
<a href="MLtonProcEnv">MLtonProcEnv</a>
</p>
</li>
<li>
<p>
<a href="MLtonProcess">MLtonProcess</a>
</p>
</li>
<li>
<p>
<a href="MLtonRandom">MLtonRandom</a>
</p>
</li>
<li>
<p>
<a href="MLtonReal">MLtonReal</a>
</p>
</li>
<li>
<p>
<a href="MLtonRlimit">MLtonRlimit</a>
</p>
</li>
<li>
<p>
<a href="MLtonRusage">MLtonRusage</a>
</p>
</li>
<li>
<p>
<a href="MLtonSignal">MLtonSignal</a>
</p>
</li>
<li>
<p>
<a href="MLtonSocket">MLtonSocket</a>
</p>
</li>
<li>
<p>
<a href="MLtonSyslog">MLtonSyslog</a>
</p>
</li>
<li>
<p>
<a href="MLtonTextIO">MLtonTextIO</a>
</p>
</li>
<li>
<p>
<a href="MLtonThread">MLtonThread</a>
</p>
</li>
<li>
<p>
<a href="MLtonVector">MLtonVector</a>
</p>
</li>
<li>
<p>
<a href="MLtonWeak">MLtonWeak</a>
</p>
</li>
<li>
<p>
<a href="MLtonWord">MLtonWord</a>
</p>
</li>
<li>
<p>
<a href="MLtonWorld">MLtonWorld</a>
</p>
</li>
</ul>
<h2 id="head-b1564f6b1512cbfa3cfcebc9a5badb6b239954f1">Values</h2>
<ul>
<li>
<p>
<tt>eq (x, y)</tt> <br>
returns true if <tt>x</tt> and <tt>y</tt> are equal as pointers. For simple types like <tt>char</tt>, <tt>int</tt>, and <tt>word</tt>, this is the same as equals. For arrays, datatypes, strings, tuples, and vectors, this is a simple pointer equality. The semantics is a bit murky.
</p>
</li>
<li class="gap">
<p>
<tt>equal (x, y)</tt> <br>
returns true if <tt>x</tt> and <tt>y</tt> are structurally equal. For equality types, this is the same as <a href="PolymorphicEquality">PolymorphicEquality</a>. For other types, it is a conservative approximation of equivalence.
</p>
</li>
<li class="gap">
<p>
<tt>hash x</tt> <br>
returns a structural hash of <tt>x</tt>. The hash function is consistent between execution of the same program, but may not be consistent between different programs.
</p>
</li>
<li class="gap">
<p>
<tt>isMLton</tt> <br>
is always true in a MLton implementation, and is always false in a stub implementation.
</p>
</li>
<li class="gap">
<p>
<tt>share x</tt> <br>
maximizes sharing in the heap for the object graph reachable from <tt>x</tt>.
</p>
</li>
<li class="gap">
<p>
<tt>shareAll ()</tt> <br>
maximizes sharing in the heap by sharing space for equivalent immutable objects. A call to <tt>shareAll</tt> performs a major garbage collection, and takes time proportional to the size of the heap.
</p>
</li>
<li class="gap">
<p>
<tt>size x</tt> <br>
returns the amount of heap space (in bytes) taken by the value of <tt>x</tt>, including all objects reachable from <tt>x</tt> by following pointers. It takes time proportional to the size of <tt>x</tt>. See below for an example.
</p>
</li>
</ul>
<h2 id="head-48c21e9f702d3a4e4ebc0ce38e1d6c7f6bf73f5b">Example of MLton.size</h2>
<a id="size"></a> <p>
This example, <tt>size.sml</tt>, demonstrates the application of <tt>MLton.size</tt> to many different kinds of objects.
</p>
<pre class=code>
<B><FONT COLOR="#A020F0">fun</FONT></B> <B><FONT COLOR="#228B22">'a</FONT></B> printSize (name: string, min: int, value: 'a): unit=
<B><FONT COLOR="#A020F0">if</FONT></B> MLton.size value >= min
<B><FONT COLOR="#A020F0">then</FONT></B>
(print <B><FONT COLOR="#BC8F8F">"The size of "</FONT></B>
; print name
; print <B><FONT COLOR="#BC8F8F">" is >= "</FONT></B>
; print (Int.toString min)
; print <B><FONT COLOR="#BC8F8F">" bytes.\n"</FONT></B>)
<B><FONT COLOR="#A020F0">else</FONT></B> ()
<B><FONT COLOR="#A020F0">val</FONT></B> l = [<B><FONT COLOR="#5F9EA0">1</FONT></B>, <B><FONT COLOR="#5F9EA0">2</FONT></B>, <B><FONT COLOR="#5F9EA0">3</FONT></B>, <B><FONT COLOR="#5F9EA0">4</FONT></B>]
<B><FONT COLOR="#A020F0">val</FONT></B> _ =
(
printSize (<B><FONT COLOR="#BC8F8F">"a char"</FONT></B>, <B><FONT COLOR="#5F9EA0">0</FONT></B>, #<B><FONT COLOR="#BC8F8F">"c"</FONT></B>)
; printSize (<B><FONT COLOR="#BC8F8F">"an int list of length 4"</FONT></B>, <B><FONT COLOR="#5F9EA0">48</FONT></B>, l)
; printSize (<B><FONT COLOR="#BC8F8F">"a string of length 10"</FONT></B>, <B><FONT COLOR="#5F9EA0">24</FONT></B>, <B><FONT COLOR="#BC8F8F">"0123456789"</FONT></B>)
; printSize (<B><FONT COLOR="#BC8F8F">"an int array of length 10"</FONT></B>, <B><FONT COLOR="#5F9EA0">52</FONT></B>, Array.tabulate (<B><FONT COLOR="#5F9EA0">10</FONT></B>, <B><FONT COLOR="#A020F0">fn</FONT></B> _ => <B><FONT COLOR="#5F9EA0">0</FONT></B>))
; printSize (<B><FONT COLOR="#BC8F8F">"a double array of length 10"</FONT></B>,
<B><FONT COLOR="#5F9EA0">92</FONT></B>, Array.tabulate (<B><FONT COLOR="#5F9EA0">10</FONT></B>, <B><FONT COLOR="#A020F0">fn</FONT></B> _ => <B><FONT COLOR="#5F9EA0">0.0</FONT></B>))
; printSize (<B><FONT COLOR="#BC8F8F">"an array of length 10 of 2-ples of ints"</FONT></B>,
<B><FONT COLOR="#5F9EA0">92</FONT></B>, Array.tabulate (<B><FONT COLOR="#5F9EA0">10</FONT></B>, <B><FONT COLOR="#A020F0">fn</FONT></B> i => (i, i + <B><FONT COLOR="#5F9EA0">1</FONT></B>)))
; printSize (<B><FONT COLOR="#BC8F8F">"a useless function"</FONT></B>, <B><FONT COLOR="#5F9EA0">0</FONT></B>, <B><FONT COLOR="#A020F0">fn</FONT></B> _ => <B><FONT COLOR="#5F9EA0">13</FONT></B>)
)
<I><FONT COLOR="#B22222">(* This is here so that the list is "useful".
* If it were removed, then the optimizer (remove-unused-constructors)
* would remove l entirely.
*)</FONT></I>
<B><FONT COLOR="#A020F0">val</FONT></B> _ = <B><FONT COLOR="#A020F0">if</FONT></B> <B><FONT COLOR="#5F9EA0">10</FONT></B> = foldl (<B><FONT COLOR="#A020F0">op</FONT></B> +) <B><FONT COLOR="#5F9EA0">0</FONT></B> l
<B><FONT COLOR="#A020F0">then</FONT></B> ()
<B><FONT COLOR="#A020F0">else</FONT></B> <B><FONT COLOR="#A020F0">raise</FONT></B> Fail <B><FONT COLOR="#BC8F8F">"bug"</FONT></B>
<B><FONT COLOR="#0000FF">local</FONT></B>
<B><FONT COLOR="#0000FF">open</FONT></B> MLton.Cont
<B><FONT COLOR="#0000FF">in</FONT></B>
<B><FONT COLOR="#A020F0">val</FONT></B> rc: int option t option ref = ref NONE
<B><FONT COLOR="#A020F0">val</FONT></B> _ =
<B><FONT COLOR="#A020F0">case</FONT></B> callcc (<B><FONT COLOR="#A020F0">fn</FONT></B> k: int option t => (rc := SOME k; throw (k, NONE))) <B><FONT COLOR="#A020F0">of</FONT></B>
NONE => ()
| SOME i => print (concat [Int.toString i, <B><FONT COLOR="#BC8F8F">"\n"</FONT></B>])
<B><FONT COLOR="#0000FF">end</FONT></B>
<B><FONT COLOR="#A020F0">val</FONT></B> _ =
(print <B><FONT COLOR="#BC8F8F">"The size of a continuation option ref is "</FONT></B>
; <B><FONT COLOR="#A020F0">if</FONT></B> MLton.size rc > <B><FONT COLOR="#5F9EA0">1000</FONT></B>
<B><FONT COLOR="#A020F0">then</FONT></B> print <B><FONT COLOR="#BC8F8F">"> 1000.\n"</FONT></B>
<B><FONT COLOR="#A020F0">else</FONT></B> print <B><FONT COLOR="#BC8F8F">"< 1000.\n"</FONT></B>)
<B><FONT COLOR="#A020F0">val</FONT></B> _ =
<B><FONT COLOR="#A020F0">case</FONT></B> !rc <B><FONT COLOR="#A020F0">of</FONT></B>
NONE => ()
| SOME k => (rc := NONE; MLton.Cont.throw (k, SOME <B><FONT COLOR="#5F9EA0">13</FONT></B>))
</PRE>
<p>
</p>
<p>
Compile and run as usual.
<pre>% mlton size.sml
% ./size
The size of a char is >= 0 bytes.
The size of an int list of length 4 is >= 48 bytes.
The size of a string of length 10 is >= 24 bytes.
The size of an int array of length 10 is >= 52 bytes.
The size of a double array of length 10 is >= 92 bytes.
The size of an array of length 10 of 2-ples of ints is >= 92 bytes.
The size of a useless function is >= 0 bytes.
The size of a continuation option ref is > 1000.
13
The size of a continuation option ref is < 1000.
</pre>
</p>
</div>
<p>
<hr>
Last edited on 2009-06-06 01:21:46 by <span title="c-67-165-143-160.hsd1.il.comcast.net"><a href="MatthewFluet">MatthewFluet</a></span>.
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