When comparing Slim vs Haml, the Slant community recommends Slim for most people. In the question“What are the best HTML preprocessors?” Slim is ranked 2nd while Haml is ranked 4th. The most important reason people chose Slim is:
Slim's documentation is well organized and detailed, every concept is thoroughly explained and it is very helpful for both advanced users and beginners.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Well organized and thorough documentation
Slim's documentation is well organized and detailed, every concept is thoroughly explained and it is very helpful for both advanced users and beginners.
Pro A good starting point
Slim is minimal and that is a good thing if you want to start from there. It can be easily extended and even supports popular packages that are used in Laravel (like Illuminate\Database (eloquent)) for example.
Pro REST based
REST fans will love the REST based architecture.
Pro Supports tie-ins for Rack-like middleware
Rack is an interface used in Ruby frameworks used to group and order modules, which most of the time are Ruby classes, and specify between them.
Slim uses a simple concept for it's middleware. By wrapping HTTP requests and responses it unifies the middleware into a single method call.
Pro Useful classes
Contains classes for managing requests, responses, cookies, logging, views, HTTP caching, and more.
Pro Flexible
Slim doesn't demand that you stick to a fixed folder structure. As long as you load Slim the right way you can do anything from there the way you like it.
Pro Extremely lightweight
Paired with swoole it's a micro service powerhouse.
Pro Open source
The Slim Framework is open source and is released under the MIT public license
Pro Extremely customizable
You can add any dependency, package or class that you want to use as a contained dependency.
Pro Supports Php 5.3 and PHP 7
Pro Makes it easy to understand the way some abstract functions and classes are built
In Django most things are abstracted, you just call some function or class without knowing how they were built, but with Slim, you end up understanding the way some abstract functions and classes are built.
Pro Hooks for executing code at different points in its life-cycle
Slim supports code hooks for executing functions at different points in time during the application's lifecycle.
Pro Easy to learn
There are plenty of learning resources available for those who want to learn Haml. The documentation is detailed and well organized, and Haml is easy to pick up.
Pro Efficient
By using indentation rather than closing tags and eliminating curly braces, Haml is fast to code.
For example
This:
<div id ="lower">
<div class="right column">
<div id="currentDate"><%= print_date %></div>
</div>
</div>
Can be written as:
%div#lower
%div.right.column
%div#currentDate= print_date
Pro Clean syntax
Haml's syntax is very clean and pleasant to look at. It doesn't use HTML tags and it's not verbose at all. The templates are easily readable.
Cons
Con Very little consistency among different versions
There have been quite some changes that break the compatibility between Slim 2 and Slim 3. Even if you learned how to work with the Slim 2, you will find that Slim 3 requires re-training.
Con Dependency injection is too weak
It is not really dependency injection, but just a configurable container.
Con Needs strong bases to create dependencies
The dependency container schema of Slim is one of the biggest PROS and CONS of the framework. It is true that this schema brings so much flexibility to add anything, but another thing that is true is that you need to have strong bases of patterns, and an extensive knowledge of your libraries to convert it into a Slim dependency.
Con Too minimal
While it's true that Slim is a microframework, it's still too minimal. When used for throwaway projects or simple prototypes, it's perfect. But in the long run, it becomes less and less useful and you end up in implementing a full custom framework in trying to tackle all the missing features.
Con Bad Performance
The rendering time with haml is slower than its competitors.
Con Whitespace sensitivity can be problematic
Haml uses indentation to define structure, rather than closing tags. Though this, in most cases, makes code more efficient to write, it can also cause problems.
Being off by one space can cause an error or change the structure of the code.
