From 87bf541f23723f6a8c7f05c89984c5df0c450ec2 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Thu, 8 Apr 2004 15:51:26 +0000
Subject: * Documented the primops.

---
 doc/manual/nix-lang-ref.xml | 100 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 97 insertions(+), 3 deletions(-)

(limited to 'doc/manual/nix-lang-ref.xml')

diff --git a/doc/manual/nix-lang-ref.xml b/doc/manual/nix-lang-ref.xml
index 19917144e..5d53063ce 100644
--- a/doc/manual/nix-lang-ref.xml
+++ b/doc/manual/nix-lang-ref.xml
@@ -4,9 +4,6 @@
   <sect1>
     <title>Grammar</title>
 
-    <para>
-    </para>
-
     <productionset>
       <title>Expressions</title>
       
@@ -97,6 +94,8 @@
           <nonterminal def="#nix.path" /> |
           <nonterminal def="#nix.uri" />
           <sbr />|
+          'true' | 'false' | 'null'
+          <sbr />|
           '(' <nonterminal def="#nix.expr" /> ')'
           <sbr />|
           '{' <nonterminal def="#nix.bind" />* '}'
@@ -180,4 +179,99 @@
     
   </sect1>
   
+
+
+  <sect1>
+    <title>Semantics</title>
+
+
+    
+    <sect2>
+      <title>Built-in functions</title>
+
+      <para>
+        The Nix language provides the following built-in function
+        (<quote>primops</quote>):
+      </para>
+
+      <variablelist>
+
+        <varlistentry>
+          <term><function>import</function>
+          <replaceable>e</replaceable></term>
+          <listitem>
+            <para>
+              Evaluates the expression <replaceable>e</replaceable>,
+              which must yield a path value.  The Nix expression
+              stored at this path in the file system is then read,
+              parsed, and evaluated.  Returns the result of the
+              evaluation of the Nix expression just read.
+            </para>
+
+            <para>
+              Example: <literal>import ./foo.nix</literal> evaluates
+              the expression stored in <filename>foo.nix</filename>
+              (in the directory containing the expression in which the
+              <function>import</function> occurs).
+            </para>
+          </listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><function>derivation</function>
+          <replaceable>e</replaceable></term>
+          <listitem>
+            <para>
+              Evaluates the expression <replaceable>e</replaceable>,
+              which must yield an attribute set.  [...]
+            </para>
+          </listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><function>baseNameOf</function>
+          <replaceable>e</replaceable></term>
+          <listitem>
+            <para>
+              Evaluates the expression <replaceable>e</replaceable>,
+              which must yield a string value, and returns a string
+              representing its <emphasis>base name</emphasis>.  This
+              is the substring following the last path separator
+              (<literal>/</literal>).
+            </para>
+
+            <para>
+              Example: <literal>baseNameOf "/foo/bar"</literal>
+              returns <literal>"bar"</literal>, and
+              <literal>baseNameOf "/foo/bar/"</literal> returns
+              <literal>""</literal>.
+            </para>
+          </listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><function>toString</function>
+          <replaceable>e</replaceable></term>
+          <listitem>
+            <para>
+              Evaluates the expression <replaceable>e</replaceable>
+              and coerces it into a string, if possible.  Only
+              strings, paths, and URIs can be so coerced.
+            </para>
+
+            <para>
+              Example: <literal>toString
+              http://www.cs.uu.nl/</literal> returns
+              <literal>"http://www.cs.uu.nl/"</literal>.
+            </para>
+          </listitem>
+        </varlistentry>
+            
+      </variablelist>
+
+    </sect2>
+
+  </sect1>
+  
+
 </chapter>
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