autotemplate

Autotemplates

This module implements a macro to automatically load templates from files based on Nim types. The way it works is fairly simple, you give it a folder and every file in that folder on the form Filename.extension will create a procedure proc toExtension(argument: Filename): string. So a simple example of:

.. code-block:: nim

import autotemplates

type Person = object name: string age: int

loadTemplates("templates") echo Person(name: "Peter", age: 29).toHtml

With a file like this in templates/Person.html:

.. code-block:: html

$name is $age years old!

Will simply output <p>Peter is 29 years old!</p>. Of course if the object has fields which themselves have templates defined for them these will be called automatically (including toExtension procs of the same signature but written by hand). The module also offers a proc to(x: auto, kind: string): string which will dynamically select the template to use based on the kind argument. This means that if you have for example a route in a web-server which can return either HTML or e.g. RSS you can simply pass "html" or "rss" into the to procedure and it will layout your object with the correct template.

For more complex types like inherited objects or case objects you need to use specially named folders. Take the example type:

.. code-block:: nim

type Person = object of RootObj name: string age: int Programmer = object of Person language: string

In order to lay out a Person object you create a file called for example Person.txt and in that file expand the $self keyword. This will look for matching types in a Person directory, so if we had Person/Programmer.txt it would use this template. Inheriting objects of course have access to the parent object fields as well as their own in the template.

To make use of case objects the system is similar, take a type like this:

.. code-block:: nim

type PersonKind = enum Programmer, NonProgrammer Person = object name: string age: int case kind: PersonKind of Programmer: programmingLanguage: string of NonProgrammer: naturalLanguage: string

To lay this out we again need a Person.txt file for example, in this file we can expand the $kind field. Normally this would simply output Programmer or NonProgrammer, but with a folder called Person.kind and files Person.kind/Programmer.txt and Person.kind/NonProgrammer.txt it will now use either of those templates to lay out the kind field.

An example of this behaviour can be found in the test in the tests folder.

The templating language used currently is onionhammer/nim-templates <https://github.com/onionhammer/nim-templates>_, but more options might be added in the future.

For a more in-depth example have a look at examples/server.nim or tests/test.nim.