30 lines
		
	
	
	
		
			1.1 KiB
		
	
	
	
		
			XML
		
	
	
	
	
	
			
		
		
	
	
			30 lines
		
	
	
	
		
			1.1 KiB
		
	
	
	
		
			XML
		
	
	
	
	
	
<chapter 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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      version="5.0"
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      xml:id="ch-expression-language">
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<title>Nix Expression Language</title>
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<para>The Nix expression language is a pure, lazy, functional
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language.  Purity means that operations in the language don't have
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side-effects (for instance, there is no variable assignment).
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Laziness means that arguments to functions are evaluated only when
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they are needed.  Functional means that functions are
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<quote>normal</quote> values that can be passed around and manipulated
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in interesting ways.  The language is not a full-featured, general
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purpose language.  Its main job is to describe packages,
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compositions of packages, and the variability within
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packages.</para>
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<para>This section presents the various features of the
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language.</para>
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<xi:include href="language-values.xml" />
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<xi:include href="language-constructs.xml" />
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<xi:include href="language-operators.xml" />
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<xi:include href="derivations.xml" />
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<xi:include href="builtins.xml" />
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</chapter>
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