diet-ng 1.2.1

Next generation Diet template compiler.

To use this package, put the following dependency into your project's dependencies section:



Diet is a generic compile-time template system based on an XML-like structure. The syntax is heavily influenced by pug (formerly "Jade") and outputting dynamic HTML is the primary goal. It supports pluggable transformation modules, as well as output modules, so that many other uses are possible.

See the preliminary Specification for a syntax overview.

This repository contains the designated successor implementation of the module of vibe.d. The current state is almost stable and feature complete and ready for pre-production testing.

DUB link Build Status


doctype html
- auto title = "Hello, <World>";
		title #{title} - example page
		h1= title
		h2 Index
			- foreach (i; 0 .. 3)
				li: a(href="##{i}") Point #{i}
		- foreach (i; 0 .. 3)
			h2(id=i) Point #{i}
				These are the #[em contents] of point #{i}. Multiple
				lines of text are contained in this paragraph.

Generated HTML output:

<!DOCTYPE html>
		<title>Hello, &lt;World&gt; - example page</title>
		<h1>Hello, &lt;World&gt;</h1>
		<ol class="pageindex">
			<li><a href="#0">Point 0</a></li>
			<li><a href="#1">Point 1</a></li>
			<li><a href="#2">Point 2</a></li>
		<h2 id="0">Point 0</h2>
		<p>These are the <em>contents</em> of point 0. Multiple
		lines of text are contained in this paragraph.</p>
		<h2 id="1">Point 1</h2>
		<p>These are the <em>contents</em> of point 1. Multiple
		lines of text are contained in this paragraph.</p>
		<h2 id="2">Point 2</h2>
		<p>These are the <em>contents</em> of point 2. Multiple
		lines of text are contained in this paragraph.</p>

Implementation goals

  • Be as fast as possible. This means moving as many operations from run time to compile time as possible.
  • Avoid any dynamic memory allocations (unless it happens in user code)
  • Let the generated code be fully @safe (unless embedded user code isn't)
  • Be customizable (filters, translation, DOM transformations, output generators), without resorting to global library state
  • Operate on ranges. HTML output is written to an output range, input ranges are supported within string interpolations and filters/translation support is supposed to be implementable using ranges (the latter part is not yet implemented).

Experimental HTML template caching

Since compiling complex Diet templates can slow down the overall compilation process, the library provides an option to cache and re-use results. It is enabled by defining the version constant DietUseCache ( "versions": ["DietUseCache"] in dub.json or versions "DietUseCache" in dub.sdl). It is not recommended to use this feature outside of the usual edit-compile-run development cycle, especially not for release builds.

Once enabled, the template compiler will look for _cached_*.d files in the "views/" folder, where the * consists of the file name of the Diet template and a unique hash value that identifies the contents of the template, as well as included/extended ones. If found, it will simply use the contents of that file instead of going through the whole compilation process.

At runtime, during initialization, the program will then output the contents of all newly compiled templates to the "views/" folder. For that reason it is currently important that the program is run with the current working directory set to the package directory! A drawback of this method is that outdated cached templates will not be deleted automatically. It is necessary to clear all _cached_* files by hand from time to time.

Note that hopefully this feature will be obsoleted soon by the [work of Stefan Koch on DMD's CTFE engine](

Authors: Sönke Ludwig

Dependencies: none

1.2.1 2017-Apr-18
1.2.0 2017-Mar-02
1.1.4 2017-Feb-23
1.1.3 2017-Feb-09
1.1.2 2017-Feb-06
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