What generic template processor should I use?

Question

This is a potentially dangerous question because interdisciplinary questions and answers will be biased, but I'll have a stab at it anyway. All in good spirit!

So, here we go. I'm writing a major editing mode for Emacs for the language that it has almost no support for yet. And I'm at the point, where I have to decide on a way to generate project files. Below is the syllabus of the task ahead:

• The templates have to represent project directory tree, not only single files.

• The resulting files are of various formats, potentially including SGML-like languages, but not limited to this variety. They also have to generate C-like source code and, eLisp source code and plain text files, like README, for example.

• The templates must be processed in a batch upon user-initiated action (as in user wants to create a project - several files must be created in the user-appointed directory). It may be beneficial to have an ability to supervise the creation, but this is less important then the ability to run the process entirely automatically.

Bonus features:

• The template language has already a user base (with a potential of reuse of existing templates).

• The templates can be used for code snippets (contain blanks which are filled interactively once the user invokes code-generating routine while editing the file).

• Obvious things like cross-platform-ness, ease of use both through graphical interface and command line.

I made a research, but I won't share my results (yet) so I won't bias the answers. The problem with answering this question is not that the answer is hard to find, but that it is hard to chose one from many.

Answer 1

Another option is Generator, which offers “language-agnostic project bootstrapping with an emphasis on simplicity”. Installation requires Node.js and npm.

Generator’s emphasis on simplicity means it is very easy to learn how to make a template. Generator also saves you from having to reference templates by file paths – it looks for templates in ~/.generator.

However, there is no way to write README or LICENSE files for the template itself without those files being copied to the generated project. Also, post-generation commands written in the Makefile will be copied to the generated Makefile, even after they are no longer of use. Finally, the ad-hoc templating language doesn’t provide a way to escape its __lowercasevariables__ – though I can’t think of a language where that limitation would be a problem.

Answer 2

I'm developing a system based on Mustache for exactly the use case that you've described. The template language itself is a very simple extension of Mustache called Groome.

I also released a command-line tool called Molt that renders Groome templates. I'd be curious to know if it does everything that you need. I'm still adding features to the tool and haven't yet announced it. Thanks.

Answer 3

I went to solve a similar problem several years aback, where I wanted to use Emacs to generate code out of a UML diagram (cogre), and also generate Makefiles from project specifications. I first tried to use Tempo, but when I tried to get the templates to nest, I ran into problems. I also looked into skeleton, but that didn't quite fit the plan either.

I ended up using Google Templates for a little bit, and liked the syntax, and developed SRecode instead, and just borrowed the good bits from Google templates. SRecode was written specifically for machine-generated code. The interaction for template insertion (aka - what tempo was written for) isn't first class in SRecode. For generating code from a data structure, however, it is very robust, and has a lot of features, and automatically filled variables. It works closely with your major mode, and allows many nested templates, with control over the nested dictionary values. There is a subsystem that will use Semantic tags and generate code from them for a couple languages. That means you can parse code in one language with Semantic, and generate code in another language with SReocde using those tags. Nifty! Many parts of CEDET Reference manuals were built that way.

The templates themselves allow looping, if statements, and include statements. There are a couple examples in SRecode for making an 'application', such as the comment writer, and EDE uses it to create Makefiles, which is almost exactly what you are trying to do.