Use a different template engine

[breard-r]

Overview

This issue tracks the criteria the template engine used to render hooks should have and which are eligible. At time of writing, none is eligible, hence the current one is kept. Please submit other crates if they are worth investigating.

Features

Dynamic templates

The crate does not require to have the templates at compile time. Hooks are defined by the user, therefore their templates are not available when ACMEd is compiled.

Jinja2-like

I really like the Jinja2 style. Not all features are required, only the most basics (variables display, basic tests and loops).

Does not have many dependencies

See issue #1
Dependencies of dependencies are counted too.

Method to count dependencies:

• Create a new empty project using cargo new --bin test_<lib_name>
• Add the lib to the Cargo.toml file
• Run cargo build
• Run cargo tree | grep -v '*' | wc -l | sed 's/$/-2/' | bc

The minus 2 is intended to remove the project and the library itself from the count.

• ✔️ : n ≤ 5
• ✅ : 5 < n ≤ 10
• ⚠️ : 10 < n ≤ 30
• ❌ : 30 < n

Does not depends on pest

ACMEd already uses nom and should not depend on a second parser.

Comparison table

Crate	Dynamic templates	Jinja2-like	Dependencies	No pest	Comment
askama	❌	✔️	33 ❌	✔️	Impossible to use in ACMEd
tera	✔️	✔️	89 ❌	❌	Would use if fewer dependencies and pest wouldn't be one of them
liquid	✔️	✔️	115 ❌	❌	Would use if fewer dependencies and pest wouldn't be one of them
templar	✔️	✔️	43 ❌	❌	Current version (0.5) unusable because of debug print
tinytemplate	✔️	⚠️	10 ✔️	✔️	Quite simple and effective
ramhorns	✔️	❌	19 ⚠️	✔️	Would use if it was a Jinja2-like and had a little fewer dependencies
handlebars	✔️	❌	45 ❌	❌	Currently used

[breard-r]

Added templar and tinytemplate. The later seems promising, I'll do more testing on it since it may be the best choice.