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<title>LanguageChanges - MLton Standard ML Compiler (SML Compiler)</title>
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We are sometimes asked to modify MLton to change the language it compiles.  In short, we are very conservative about making such changes.  There are a number of reasons for this. 
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<p>
 The <a href="DefinitionOfStandardML">Definition of Standard ML</a> is an  extremely high standard of specification.  The value of the  Definition would be significantly diluted by changes that are not  specified at an equally high level, and the dilution increases with  the complexity of the language change and its interaction with other  language features.  
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 The SML community is small and there are a    <a href="StandardMLImplementations">number of SML implementations</a>.  Without  an agreed-upon standard, it becomes very difficult to port programs  between compilers, and the community would be balkanized. 
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 Our main goal is to enable programmers to be as effective as   possible with MLton/SML.  There are a number of improvements other  than language changes that we could spend our time on that would  provide more benefit to programmers. 
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 The more the language that MLton compiles changes over time, the  more difficult it is to use MLton as a stable platform for serious  program development. 
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Despite these drawbacks, we have extended SML in a couple of cases. 
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 <a href="ForeignFunctionInterface"> Foreign function interface</a> 
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 <a href="MLBasis"> ML Basis system</a> 
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We allow these language extensions because they provide functionality that is impossible to achieve without them.  The Definition does not define a foreign function interface.  So, we must either extend the language or greatly restrict the class of programs that can be written.  Similarly, the Definition does not provide a mechanism for namespace control at the module level, making it impossible to deliver packaged libraries and have a hope of users using them without name clashes.  The <a href="MLBasis"> ML Basis system</a> addresses this problem.  We have also provided a formal specification of the ML Basis system at the level of the Definition. 
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<h2 id="head-a4bc8bf5caf54b18cea9f58e83dd4acb488deb17">Also see</h2>

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 <a class="external" href="http://mlton.org/pipermail/mlton/2004-August/016165.html"><img src="moin-www.png" alt="[WWW]" height="11" width="11">http://mlton.org/pipermail/mlton/2004-August/016165.html</a> 
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 <a class="external" href="http://mlton.org/pipermail/mlton-user/2004-December/000320.html"><img src="moin-www.png" alt="[WWW]" height="11" width="11">http://mlton.org/pipermail/mlton-user/2004-December/000320.html</a> 
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Last edited on 2005-09-06 23:28:57 by <span title="cfs34.cs.cornell.edu"><a href="MatthewFluet">MatthewFluet</a></span>.
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