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<a href="MLBasis">ML Basis</a> annotations control options that affect the elaboration of SML source files.  Conceptually, a basis file is elaborated in a default annotation environment (just as it is elaborated in an empty basis).  The declaration <tt>ann&nbsp;</tt><tt>"</tt><em>ann</em><tt>"</tt><tt>&nbsp;in&nbsp;</tt><em>basdec</em><tt>&nbsp;end</tt> merges the annotation <em>ann</em> with the "current" annotation environment for the elaboration of <em>basdec</em>. To allow for future expansion, <tt>"</tt><em>ann</em><tt>"</tt> is lexed as  a single SML string constant.  To conveniently specify multiple  annotations, the following derived form is provided: 
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<tt>ann&nbsp;</tt><tt>"</tt><em>ann</em><tt>"</tt><tt>&nbsp;</tt>(<tt>"</tt><em>ann</em><tt>"</tt>)+<tt>&nbsp;in&nbsp;</tt><em>basdec</em><tt>&nbsp;end</tt><tt>&nbsp;==&gt;&nbsp;</tt> <tt>ann&nbsp;</tt><tt>"</tt><em>ann</em><tt>"</tt><tt>&nbsp;in&nbsp;ann&nbsp;</tt>(<tt>"</tt><em>ann</em><tt>"</tt>)+<tt>&nbsp;in&nbsp;</tt><em>basdec</em><tt>&nbsp;end</tt><tt>&nbsp;end</tt></td>
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<p>
Here are the available annotations.  In the explanation below, for annotations that take an argument, the first value listed is the default. 
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 <tt>allowFFI&nbsp;{false|true}&nbsp;</tt>  <br>
If <tt>true</tt>, allow <tt>_address</tt>, <tt>_export</tt>, <tt>_import</tt>,  and <tt>_symbol</tt> expressions to appear in source files.  See   <a href="ForeignFunctionInterface">ForeignFunctionInterface</a>. 
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 <tt>forceUsed&nbsp;</tt>  <br>
Force all identifiers in the basis denoted by the body of the  <tt>ann</tt> to be considered used; use in conjunction with   <tt>warnUnused&nbsp;true</tt>. 
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 <tt>nonexhaustiveExnMatch&nbsp;{default|ignore}&nbsp;</tt>  <br>
If <tt>ignore</tt>, suppress errors and warnings about nonexhaustive  matches that arise solely from unmatched exceptions.  If  <tt>default</tt>, follow the behavior of <tt>nonexhaustiveMatch</tt>.  
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 <tt>nonexhaustiveMatch&nbsp;{warn|error|ignore}&nbsp;</tt>  <br>
If <tt>error</tt> or <tt>warn</tt>, report nonexhaustive matches.  An  error will abort a compile, while a warning will not. 
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 <tt>redundantMatch&nbsp;{warn|error|ignore}&nbsp;</tt>  <br>
If <tt>error</tt> or <tt>warn</tt>, report redundant matches.  An  error will abort a compile, while a warning will not. 
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 <tt>sequenceNonUnit&nbsp;{ignore|error|warn}&nbsp;</tt>  <br>
If <tt>error</tt> or <tt>warn</tt>, report when <tt>e1</tt> is not of type  <tt>unit</tt> in the sequence expression <tt>(e1;&nbsp;e2)</tt>.  This can be  helpful in detecting curried applications that are mistakenly not  hully applied.  To silence spurious messages, you can use   <tt>ignore&nbsp;e1</tt>. 
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 <tt>warnUnused&nbsp;{false|true}&nbsp;</tt>  <br>
Report unused identifiers. 
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<h2 id="head-3f170caead65df254d786032a409a6f6d204bca6">Next Steps</h2>

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<p>
 <a href="MLBasisAnnotationExamples">MLBasisAnnotationExamples</a> 
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Last edited on 2007-08-23 17:10:20 by <span title="fenrir.uchicago.edu"><a href="MatthewFluet">MatthewFluet</a></span>.
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