Passing options to Haml on the command line

Question

I'm using Haml from the command-line to do a basic transform of one .haml file to .html, like this:

> haml input.haml output.html

Thing is, this produces single-quotes around attributes in the resulting HTML. So how to I pass in the :attr_wrapper => '"' option from the command-line?

Alternatively, can I just globally set :attr_wrapper to a double-quote?

Answer 1

I don't know a way to specify that option to the standard command-line client. You can globally patch the default by changing haml/engine.rb line 73 (in Haml 2.2.2) to read

:attr_wrapper => '"',

That's for Haml 2.2.2. It's different in earlier versions. If you're still using one of those, you can just to a text search for ":attr_wrapper =>" and it will find the correct line.

Answer 2

I don't know of a way to pass it as an argument, but HAML is easy to use programmatically:

require 'haml'

template = ARGV.length > 0 ? File.read(ARGV.shift) : STDIN.read
haml_engine = Haml::Engine.new(template, :attr_wrapper => '"')
file = ARGV.length > 0 ? File.open(ARGV.shift, 'w') : STDOUT
file.write(haml_engine.render)
file.close

Nothing pretty, but it'll open the first argument given (or STDIN if no arguments are given), and pass rendered output to the second argument (or STDOUT of not given).

Answer 3

What I've ended up doing is adding the following to haml/exec.rb at ~line 302

    opts.on('-q', '--double-quote-attribs',
            'Set attribute wrapper to double-quotes (default is single).') do
      @options[:for_engine][:attr_wrapper] = '"'
    end

This adds a dedicated option to do what I need.

I'm not quite sure what the rationale for using single-quotes by default is; double-quotes would make a more sensible default, I would have thought. Having said that, they are perfectly valid.

I submitted this update as a patch and it'll be included in version 2.4