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<link rel="Appendix" title="mlb-formal.pdf" href="http://mlton.org/pages/MLBasis/attachments/mlb-formal.pdf">
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The ML Basis system extends Standard ML to support programming-in-the-very-large, namespace management at the module level, separate delivery of library sources, and more.  While Standard ML modules are a sophisticated language for programming-in-the-large, it is difficult, if not impossible, to accomplish a number of routine namespace management operations when a program draws upon multiple libraries provided by different vendors.   <p>
The ML Basis system is a simple, yet powerful, approach that builds upon the programmer's intuitive notion (and the <a href="DefinitionOfStandardML"> Definition of Standard ML's</a> formal notion) of the top-level environment (a <em>basis</em>).  The system is designed as a natural extension of <a href="StandardML"> Standard ML</a>; the formal specification of the ML Basis system (<a href="http://mlton.org/pages/MLBasis/attachments/mlb-formal.pdf"><img src="moin-www.png" alt="[WWW]" height="11" width="11">pdf</a>) is given in the style of the Definition. 
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Here are some of the key features of the ML Basis system: 
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Explicit file order: The order of files (and, hence, the order of  evaluation) in the program is explicit.  The ML Basis system's  semantics are structured in such a way that for any well-formed  project, there will be exactly one possible interpretation of the  project's syntax, static semantics, and dynamic semantics. 
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Implicit dependencies: A source file (corresponding to a SML  top-level declaration) is elaborated in the environment described by  preceding declarations.  It is not necessary to explicitly list the  dependencies of a file. 
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Scoping and renaming: The ML Basis system provides mechanisms for  limiting the scope of (i.e, hiding) and renaming identifiers. 
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No naming convention for finding the file that defines a module.  To import a module, its defining file must appear in some ML Basis  file. 
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<h2 id="head-11fc14203dd0f4441645a9c34d5dd022905f56e4">Next steps</h2>

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 <a href="MLBasisSyntaxAndSemantics">MLBasisSyntaxAndSemantics</a> 
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 <a href="MLBasisExamples">MLBasisExamples</a> 
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 <a href="MLBasisPathMap">MLBasisPathMap</a> 
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 <a href="MLBasisAnnotations">MLBasisAnnotations</a> 
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 <a href="MLBasisAvailableLibraries">MLBasisAvailableLibraries</a> 
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Last edited on 2005-12-01 20:09:32 by <span title="ppp-71-139-183-221.dsl.snfc21.pacbell.net"><a href="StephenWeeks">StephenWeeks</a></span>.
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