* Documented nix-instantiate --xml, --strict.

* Added an example to the nix-build section.
This commit is contained in:
Eelco Dolstra 2006-10-05 20:41:57 +00:00
parent 8396b59286
commit 99ef620c8c
4 changed files with 104 additions and 6 deletions

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@ -117,4 +117,20 @@ except for <option>--arg</option> and <option>--attr</option> /
</refsection>
<refsection><title>Examples</title>
<screen>
$ nix-build pkgs/top-level/all-packages.nix -A firefox
store derivation is /nix/store/qybprl8sz2lc...-firefox-1.5.0.7.drv
/nix/store/d18hyl92g30l...-firefox-1.5.0.7
$ ls -l result
lrwxrwxrwx <replaceable>...</replaceable> result -> /nix/store/d18hyl92g30l...-firefox-1.5.0.7
$ ls ./result/bin/
firefox firefox-config</screen>
</refsection>
</refentry>

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@ -20,10 +20,16 @@
</arg>
<arg><option>--add-root</option> <replaceable>path</replaceable></arg>
<arg><option>--indirect</option></arg>
<group choice='opt'>
<arg choice='plain'><option>--parse-only</option></arg>
<arg choice='plain'><option>--eval-only</option></arg>
</group>
<arg>
<group choice='req'>
<arg choice='plain'><option>--parse-only</option></arg>
<arg choice='plain'>
<option>--eval-only</option>
<arg><option>--strict</option></arg>
</arg>
</group>
<arg><option>--xml</option></arg>
</arg>
<arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
@ -85,6 +91,31 @@ common options.</para>
</varlistentry>
<varlistentry><term><option>--xml</option></term>
<listitem><para>When used with <option>--parse-only</option> and
<option>--eval-only</option>, print the resulting expression as an
XML representation of the abstract syntax tree rather than as an
ATerm. The schema is the same as that used by the <link
linkend="builtin-toXML"><function>toXML</function>
built-in</link>.</para></listitem>
</varlistentry>
<varlistentry><term><option>--strict</option></term>
<listitem><para>When used with <option>--eval-only</option>,
recursively evaluate list elements and attributes. Normally, such
sub-expressions are left unevaluated (since the Nix expression
language is lazy).</para>
<warning><para>This option can cause non-termination, because lazy
data structures can be infinitely large.</para></warning>
</listitem>
</varlistentry>
</variablelist>
</refsection>
@ -92,6 +123,9 @@ common options.</para>
<refsection><title>Examples</title>
<para>Instantiating store derivations from a Nix expression, and
building them using <command>nix-store</command>:
<screen>
$ nix-instantiate test.nix <lineannotation>(instantiate)</lineannotation>
/nix/store/cigxbmvy6dzix98dxxh9b6shg7ar5bvs-perl-BerkeleyDB-0.26.drv
@ -104,6 +138,54 @@ $ ls -l /nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26
dr-xr-xr-x 2 eelco users 4096 1970-01-01 01:00 lib
...</screen>
</para>
<para>Parsing and evaluating Nix expressions:
<screen>
$ echo '"foo" + "bar"' | nix-instantiate --parse-only -
OpPlus(Str("foo"),Str("bar"))
$ echo '"foo" + "bar"' | nix-instantiate --eval-only -
Str("foobar")
$ echo '"foo" + "bar"' | nix-instantiate --eval-only --xml -
<![CDATA[<?xml version='1.0' encoding='utf-8'?>
<expr>
<string value="foobar" />
</expr>]]></screen>
</para>
<para>The difference between non-strict and strict evaluation:
<screen>
$ echo 'rec { x = "foo"; y = x; }' | nix-instantiate --eval-only --xml -
<replaceable>...</replaceable><![CDATA[
<attr name="x">
<string value="foo" />
</attr>
<attr name="y">
<unevaluated />
</attr>]]>
<replaceable>...</replaceable></screen>
Note that <varname>y</varname> is left unevaluated (the XML
representation doesnt attempt to show non-normal forms).
<screen>
$ echo 'rec { x = "foo"; y = x; }' | nix-instantiate --eval-only --xml --strict -
<replaceable>...</replaceable><![CDATA[
<attr name="x">
<string value="foo" />
</attr>
<attr name="y">
<string value="foo" />
</attr>]]>
<replaceable>...</replaceable></screen>
</para>
</refsection>

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@ -286,4 +286,4 @@
</variablelist>
</section>
</section>

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@ -1769,7 +1769,7 @@ in foo</programlisting>
</varlistentry>
<varlistentry><term><function>builtins.toXML</function> <replaceable>e</replaceable></term>
<varlistentry xml:id='builtin-toXML'><term><function>builtins.toXML</function> <replaceable>e</replaceable></term>
<listitem><para>Return a string containing an XML representation
of <replaceable>e</replaceable>. The main application for