39 lines
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39 lines
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<title>Conclusion - Boost.Outcome documentation</title>
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<div class="titlepage"><div><div><h1 style="clear: both">Conclusion</h1></div></div></div>
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<p>This worked example was in fact excessively complex: a quicker route
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to achieving the same thing would be to add explicit converting constructors
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to <code>app::error_code</code> for each of the third party library <code>E</code> types.
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One then could have saved oneself with having to bother injecting
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custom converters into the <code>BOOST_OUTCOME_V2_NAMESPACE::convert</code> namespace.
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If you control your application’s <code>E</code> type, then that is probably a
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better, and certainly simpler, approach.</p>
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<p>However there are occasions when you don’t have control over the
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implementation of the destination <code>E</code> type e.g. in callbacks. Outcome’s <code>ValueOrError</code>
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infrastructure lets you inject custom interop code for any pair
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of incommensurate third party <code>E</code> types, without needing to modify either’s
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source code.</p>
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<p>This is without doubt a “power users” feature, but
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one which will prove useful as <code>T|E</code> based C++ code proliferates.</p>
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</div><p><small>Last revised: February 11, 2019 at 13:38:04 UTC</small></p>
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