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Uri Guttman > Template-Simple-0.06 > TODO


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Even though this template system is simple, that doesn't mean it can't be extended in many ways. Here are some features and designs that would be good extensions which add useful functionality without adding too much complexity.

Closure call tree

The internal format can be a nested set of closures. Each closure would contain private data such as fixed text parts of the original template, lists of other closures to run, etc. It is trivial to write a basic closure generator which will make build this tree a simple task.

Code ref call tree

This format is a Perl data tree where the nodes have a code reference and its args (which can be nested instances of the same nodes). Instead of executing this directly, you will need a small interpreter to execute all the code refs as it runs through the tree.

This would make for a challenging project to any intermediate Perl hacker. It just involves knowing recursion, data trees and code refs. Contact me if you are interested in doing this.

Cased Hash Lookups

One possible option is to allow hash renderings to always use upper or lower cased keys in their lookups.

Render tokens before includes and chunks

Currently tokens are rendered after includes and chunks. If tokens were rendered in a pass before the others, the include and chunk names could be dynamically set. This would make it harder to precompile templates as too much would be dynamic, i.e. you won't know what the fixed text to parse out is since anything can be included at render time. But the extra flexibility of changing the include and chunk names would be interesting. It could be done easily and enabled by an option.


There are two different potential areas in Template::Simple that could use plugins. The first is with the rendering of chunkas and dispatching based on the data type. This dispatch table can easily be replaced by loaded modules which offer a different way to render. These include the precompiled renderers mentioned above. The other area is with code references as the data type. By defining a closure (or a closure making) API you can create different code refs for the rendering data. The range of plugins is endless some of the major template modules have noticed. One idea is to make a closure which contains a different Template::Simple object than the current one. This will allow rendering of a nested chunk with different rules than the current chunk being rendered.

Data Escaping

Some templaters have options to properly escape data for some types of text files such as html. this can be done with some variant of the _render_hash routine which also does the scalar rendering (which is where data is rendered). The rendering scalars code could be factored out into a set of subs one of which is used based on any escaping needs.

Data Tree is an Object

This is a concept I don't like but it was requested so it goes into the TODO file. Currently render can only be passed a regular (unblessed) ref (or a scalar) for its data tree. Passing in an object would break encapsulation and force the object layout to be a hash tree that matches the layout of the template. I doubt that most objects will want to be organized to match a template. I have two ideas, one is that you add a method to that object that builds up a proper (unblessed) data tree to pass to render. The other is by subclassing Template::Simple and overriding render with a sub that does take an object hash and it can unbless it or build a proper data tree and then call render in SUPER::. A quick solution is to use reftype (from Scalar::Utils) instead of ref to allow object hashes to be passed in.

Includes and Closure Synergy

By pairing up an include template along with code that can generate the appropriate data tree for its rendering, you can create a higher level template framework (the synergy). Additional code can be associated with them that will handle input processing and verification for the templates (e.g. web forms) that need it. A key to this will be making all the closures for the data tree. This can be greatly simplified by using a closure maker sub that can create all the required closures.

Metafields and UI Generation

Taking the synergy up to a much higher level is the concept of meta knowledge of fields which can generate templates, output processing (data tree generation), input processing, DB backing and more. If you want to discuss such grandiose wacky application schemes in a long rambling mind bending conversation, please contact me.

More Examples and Idioms

As I convert several scripts over to this module (they all used the hack version), I will add them to an examples section or possibly put them in another (pod only) module. Similarly the Idioms section needs rendering and could be also put into a pod module. One goal requested by an early alpha tester is to keep the primary docs as simple as the markup itself. This means moving all the extra stuff (and plenty of that) into other pod modules. All the pod modules would be in the same cpan tarball so you get all the docs and examples when you install this.


This method render the only INCLUDE markups of a template and it returns a list of the file paths that were found and loaded. It is meant to be used to build up a dependency list of included templates for a main template. Typically this can be called from a script (see TODO) that will do this for a set of main templates and will generate Makefile dependencies for them. Then you can regenerate rendered templates only when any of their included templates have changed. It takes a single argument of a template.

UNKNOWN: will this require a clearing of the cache or will it do the right thing on its own? or will it use the file path cache?

        my @dependencies =
                $tmpl->get_dependencies( '[%INCLUDE top_level%]' );

find templates and tests

deep nesting tests

greedy tests

methods pod

slurp dependency in

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