GTX - Minimal Template Engine

GTX is a minimal template engine that transpiles to ERB before using it to generate the output.

As opposed to ERB, GTX is a code-first template engine - where Ruby code does not need to be enclosed in tags. Instead, the output of the template needs to be marked with a "Greater Than" sign (hence the name).

$ gem install gtx

GTX converts your template code to ERB before rendering its output.

> any text
> inline code: {{ "hello " * 3 }}
>          or: <%= "world " * 3 %>

3.times do |i|
  > loopy text {{ i + 1 }}
end

= user.welcome_message

any text
inline code: <%= "hello " * 3 %>
         or: <%= "world " * 3 %>

<%- 3.times do |i| -%>
loopy text <%= i + 1 %>
<%- end -%>

<%= user.welcome_message %>

The conversion is specifically kept at 1:1 line ratio, so that the correct line number can be referenced in case of an error.

Lines starting with > are treated as output. Any number of spaces before and one space after the > are ignored:

> this line will output as is

Using {{ ... }} in an output line executes inline ruby code, as if it is ERB's <%= ... %> syntax:

> any ruby code: {{ "hello " * 3 }}

Lines starting with = can be used to execute ruby code that returns a string that is expected to be a part of the output.

= user.welcome_message(:morning)
# which is a shortcut to:
> {{ user.welcome_message(:morning) }}

Any other line, will be treated as Ruby code and will be enclosed using ERB's <%- ... -%> syntax.

See the example template for additional nuances.

require 'gtx'

# Create an instance
path = "path/to/template_file"
template = File.read path
gtx = GTX.new template, filename: path

# Parse it with optional context
gtx.parse any_object

# ... or with local binding
gtx.parse binding

# Get the ERB source
gtx.erb_source

# ... or the ERB object
gtx.erb

require 'gtx'

# One-liner render template from file
GTX.render_file path

# ... with a context or Binding object
GTX.render_file path, context: any_object

# Get an instance, and parse later
gtx = GTX.load_file path
gtx.parse optional_context_object

# Render from string
GTX.render string, context: optional_object, filename: optional_filename

GTX was created to provide a code-first alternative to ERB, specifically for the code generation templates used by Bashly. Enclosing Ruby code inside ERB tags, and ensuring there are no excess empty lines in the ERB template yielded some hard-to-maintain templates.

If you experience any issue, have a question or a suggestion, or if you wish to contribute, feel free to open an issue.