diff options
Diffstat (limited to 'doc/manual/writing-nix-expressions.xml')
| -rw-r--r-- | doc/manual/writing-nix-expressions.xml | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/doc/manual/writing-nix-expressions.xml b/doc/manual/writing-nix-expressions.xml index c5b355ea0469..71cd84b072b4 100644 --- a/doc/manual/writing-nix-expressions.xml +++ b/doc/manual/writing-nix-expressions.xml @@ -851,13 +851,26 @@ default value in an attribute selection using the will evaluate to <literal>"Xyzzy"</literal> because there is no <varname>c</varname> attribute in the set.</para> -<para>You can use arbitrary string constants as attribute names by -enclosing them in quotes: +<para>You can use arbitrary double-quoted strings as attribute +names: <programlisting> -{ "foo bar" = 123; "nix-1.0" = 456; }."foo bar" </programlisting> +{ "foo ${bar}" = 123; "nix-1.0" = 456; }."foo ${bar}" +</programlisting> + +This will evaluate to <literal>123</literal> (Assuming +<literal>bar</literal> is antiquotable). In the case where an +attribute name is just a single antiquotation, the quotes can be +dropped: + +<programlisting> +{ foo = 123; }.${bar} or 456 </programlisting> + +This will evaluate to <literal>123</literal> if +<literal>bar</literal> evaluates to <literal>"foo"</literal> when +coerced to a string and <literal>456</literal> otherwise (again +assuming <literal>bar</literal> is antiquotable).</para> -This will evaluate to <literal>123</literal>.</para> </simplesect> |