haml2html

haml2html converts Haml templates to Rails ERB templates. It is built for Rails app migrations where rendered HTML equivalence matters more than preserving original source formatting.

Install

gem install haml2html

Or in a Gemfile:

gem "haml2html"

CLI

haml2html app/views/posts/show.html.haml app/views/posts/show.html.erb
haml2html --stdin < app/views/posts/show.html.haml

The CLI writes to stdout unless an output path is provided. Unsupported syntax is reported with file and line diagnostics and exits nonzero.

Ruby API

require "haml2html"

erb = Haml2html::Converter.new("%p= post.title\n", filename: "show.html.haml").render

Examples

Haml:

= form_with model: post do |form|
  = form.text_field :title

ERB:

<%= form_with model: post do |form| %>
  <%= form.text_field :title %>
<% end %>

Haml:

:ruby
  if published
    status = "Published"
  else
    status = "Draft"
  end
%p= status

ERB:

<%
if published
  status = "Published"
else
  status = "Draft"
end
%>
<p><%= status %></p>

Supported

  • Haml tags, nesting, static attributes, text, interpolation.
  • Ruby output and control flow: =, !=, - if, - each do, and similar blocks.
  • Public comments and silent comments.
  • :plain, :escaped, :javascript, :css, :erb, and :ruby filters.
  • Dynamic Haml attributes through Rails tag.attributes.

Limitations

This is a migration tool, not a full source-preserving formatter. Output whitespace and quote style may differ from Haml output, while rendered HTML should remain equivalent for supported constructs. Unsupported filters or nodes fail with diagnostics instead of emitting known-wrong ERB.

Object references such as %div[user] are not converted yet.