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author | Mx Kookie <kookie@spacekookie.de> | 2020-10-31 19:35:09 +0100 |
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committer | Mx Kookie <kookie@spacekookie.de> | 2020-10-31 19:35:09 +0100 |
commit | c4625b175f8200f643fd6e11010932ea44c78433 (patch) | |
tree | bce3f89888c8ac3991fa5569a878a9eab6801ccc /infra/libkookie/nixpkgs/doc/functions/generators.xml | |
parent | 49f735974dd103039ddc4cb576bb76555164a9e7 (diff) | |
parent | d661aa56a8843e991261510c1bb28fdc2f6975ae (diff) |
Add 'infra/libkookie/' from commit 'd661aa56a8843e991261510c1bb28fdc2f6975ae'
git-subtree-dir: infra/libkookie
git-subtree-mainline: 49f735974dd103039ddc4cb576bb76555164a9e7
git-subtree-split: d661aa56a8843e991261510c1bb28fdc2f6975ae
Diffstat (limited to 'infra/libkookie/nixpkgs/doc/functions/generators.xml')
-rw-r--r-- | infra/libkookie/nixpkgs/doc/functions/generators.xml | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/infra/libkookie/nixpkgs/doc/functions/generators.xml b/infra/libkookie/nixpkgs/doc/functions/generators.xml new file mode 100644 index 000000000000..9ce1f85eb173 --- /dev/null +++ b/infra/libkookie/nixpkgs/doc/functions/generators.xml @@ -0,0 +1,74 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + xml:id="sec-generators"> + <title>Generators</title> + + <para> + Generators are functions that create file formats from nix data structures, e. g. for configuration files. There are generators available for: <literal>INI</literal>, <literal>JSON</literal> and <literal>YAML</literal> + </para> + + <para> + All generators follow a similar call interface: <code>generatorName configFunctions data</code>, where <literal>configFunctions</literal> is an attrset of user-defined functions that format nested parts of the content. They each have common defaults, so often they do not need to be set manually. An example is <code>mkSectionName ? (name: libStr.escape [ "[" "]" ] name)</code> from the <literal>INI</literal> generator. It receives the name of a section and sanitizes it. The default <literal>mkSectionName</literal> escapes <literal>[</literal> and <literal>]</literal> with a backslash. + </para> + + <para> + Generators can be fine-tuned to produce exactly the file format required by your application/service. One example is an INI-file format which uses <literal>: </literal> as separator, the strings <literal>"yes"</literal>/<literal>"no"</literal> as boolean values and requires all string values to be quoted: + </para> + +<programlisting> +with lib; +let + customToINI = generators.toINI { + # specifies how to format a key/value pair + mkKeyValue = generators.mkKeyValueDefault { + # specifies the generated string for a subset of nix values + mkValueString = v: + if v == true then ''"yes"'' + else if v == false then ''"no"'' + else if isString v then ''"${v}"'' + # and delegats all other values to the default generator + else generators.mkValueStringDefault {} v; + } ":"; + }; + +# the INI file can now be given as plain old nix values +in customToINI { + main = { + pushinfo = true; + autopush = false; + host = "localhost"; + port = 42; + }; + mergetool = { + merge = "diff3"; + }; +} +</programlisting> + + <para> + This will produce the following INI file as nix string: + </para> + +<programlisting> +[main] +autopush:"no" +host:"localhost" +port:42 +pushinfo:"yes" +str\:ange:"very::strange" + +[mergetool] +merge:"diff3" +</programlisting> + + <note> + <para> + Nix store paths can be converted to strings by enclosing a derivation attribute like so: <code>"${drv}"</code>. + </para> + </note> + + <para> + Detailed documentation for each generator can be found in <literal>lib/generators.nix</literal>. + </para> +</section> |