···

       
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 </para>

     

       
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 <xi:include href="functions/library.xml" />

     

       
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 <xi:include href="functions/generators.xml" />

     

       
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 <xi:include href="functions/debug.xml" />

     

       
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 <xi:include href="functions/debug.section.xml" />

     

       
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 <xi:include href="functions/prefer-remote-fetch.xml" />

     

       
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 <xi:include href="functions/nix-gitignore.section.xml" />

     

       
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</chapter>

     

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# Debugging Nix Expressions {#sec-debug}

     

       
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Nix is a unityped, dynamic language, this means every value can potentially appear anywhere. Since it is also non-strict, evaluation order and what ultimately is evaluated might surprise you. Therefore it is important to be able to debug nix expressions.

     

       
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In the `lib/debug.nix` file you will find a number of functions that help (pretty-)printing values while evaluation is running. You can even specify how deep these values should be printed recursively, and transform them on the fly. Please consult the docstrings in `lib/debug.nix` for usage information.

     

···

       
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<section xmlns="http://docbook.org/ns/docbook"

     

       
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         xmlns:xlink="http://www.w3.org/1999/xlink"

     

       
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         xmlns:xi="http://www.w3.org/2001/XInclude"

     

       
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         xml:id="sec-debug">

     

       
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 <title>Debugging Nix Expressions</title>

     

       
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 <para>

     

       
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  Nix is a unityped, dynamic language, this means every value can potentially appear anywhere. Since it is also non-strict, evaluation order and what ultimately is evaluated might surprise you. Therefore it is important to be able to debug nix expressions.

     

       
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 </para>

     

       
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 <para>

     

       
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  In the <literal>lib/debug.nix</literal> file you will find a number of functions that help (pretty-)printing values while evaluation is runnnig. You can even specify how deep these values should be printed recursively, and transform them on the fly. Please consult the docstrings in <literal>lib/debug.nix</literal> for usage information.

     

       
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 </para>

     

       
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</section>