action_view.cr

A Crystal port of Rails ActionView 8.1.4 — ERB templates, layouts, partials, the form builder and view helpers. Namespace ActionView mirrors the original 1:1; templates keep ERB syntax and are compiled into render methods at build time (via a run() template processor, like the stdlib's ECR). <%= %> auto-escapes; a SafeString type marks safe HTML. Parity is verified against the real gem with oracle specs (151 examples, 0 failures).

⚠️ EXPERIMENTAL FRAMEWORK, DO NOT USE IN PRODUCTION YET.

Installation

dependencies:
  action_view_cr:
    github: OrelSokolov/action_view.cr

shards install

Requires Crystal >= 1.21.0; pairs with active_support.cr and action_pack.cr (routes/params).

Usage

Templates are Rails-compatible ERB (app/views/<controller>/<action>.html.erb):

<%# app/views/posts/show.html.erb %>
<h1><%= @post.title %></h1>
<%= link_to "Edit", edit_post_path(@post) %>

<%= form_with model: @post do |f| %>
  <%= f.label :title %>
  <%= f.text_field :title %>
  <%= f.submit %>
<% end %>

# The application declares partials and their local types at compile time:
compile_partials({
  "shared/post" => {post: Post},
})

Feature comparison vs actionview 8.1.4

Rendering

Feature	Original (actionview)	Port (action_view.cr)	Status
ERB action templates + layouts (`yield`, nested layouts)	✅	Compile-time render methods; Rails 8.1 newline semantics (trailing `\n` chomp on action templates)	✅
`content_for` / `provide` / `content_for?`, `capture`, `concat`	✅	Same	✅
`render partial: "shared/post", locals: {...}`, collection render (`render @posts` → `_post.erb`, `<name>_counter`, `<name>_iteration`)	✅	Locals are real typed arguments of the compiled method; counter is 0-based (Rails 7.1+ behavior, oracle-confirmed)	🔶
Controller instance variables visible in views	✅	Same	✅

Form helpers

Feature	Original	Port	Status
`form_with model: @post do \|f\|` (+ `url:`, `scope:`), `form_tag` + `*_tag` helpers	✅	Same, incl. CSRF authenticity token in non-GET forms (`authenticity_token: false` to disable)	✅
`FormBuilder`: `label, text_field, password_field, hidden_field, text_area, check_box, radio_button, file_field, select, collection_select, grouped_collection_select, submit, button, email_field, number_field, date_field, ...`, `field_id/field_name`	✅	Same; models implement the `ActionView::FormModel` interface (`form_scope`/`form_attributes`/`form_persisted?`)	✅
`fields_for` (view-level + `FormBuilder#fields_for`)	✅	Byte-identical nested names `user[posts_attributes][0][title]`, auto `hidden_field :id` after the block for persisted children, `child_index:`/`include_id:`	✅
Nested-attributes index naming (`post[comments_attributes][0][_destroy]`)	✅	Same	✅

Content, tags, text & numbers

Feature	Original	Port	Status
Output safety (`html_safe`, `raw`, `safe_join`, `escape_once`)	✅	SafeString marker type	✅
`content_tag`, `tag("br")`, `tag.br` dot form	✅	Dot form is a fixed list of ~110 HTML elements, macro-generated	🔶
URL helpers: `link_to` (options/block), `link_to_if/unless`, `button_to`, `current_page?`, `mail_to/phone_to/sms_to`	✅	Same	✅
`url_for(model)` polymorphic URLs	✅	Not ported	⬜
Text: `pluralize, truncate, excerpt, highlight, word_wrap, simple_format, cycle/...`	✅	Same	✅
Numbers: `number_to_currency/delimiter/precision/human_size/human/percentage/phone`	✅	Same (locale data)	✅
`debug`, `distance_of_time_in_words`, `time_ago_in_words`, `t/l` (I18n)	✅	Same	✅
Asset helpers: `stylesheet_link_tag, javascript_include_tag, javascript_tag, image_tag, video_tag, audio_tag, favicon_link_tag, csrf_meta_tags, csp_meta_tag`	✅	Same; fingerprint manifest `public/assets/manifest.json` + `compute_asset_path` (Sprockets/Propshaft are not ported)	🔶
`sanitize, strip_tags, strip_links`	✅	Needs an HTML parser (lexbor)	⬜
Fragment cache: `cache`/`cache_if`/`cache_unless`/`fragment_cache_key`	✅	Explicit string keys, `ActionView.perform_caching`/`cache_store` (NullStore by default)	🔶
Russian-doll cache keys (template digest, dependency tracker), array/object keys	✅	Not ported	⬜

Vite integration (beyond actionview — ports vite_rails 3.0.19 / vite_ruby 3.9.2)

Feature	Original (vite_rails)	Port	Status
`vite_javascript_tag` (ESM + modulepreload + CSS chunks), `vite_stylesheet_tag`, `vite_asset_path`, `vite_image_tag`	✅	Byte-identical output vs oracle; vite 5/6 manifest format	✅
Dev-server detection & dev tags (`vite_client_tag`, `vite_react_refresh_tag`)	✅	TCP probe (1 s cache), dev lookup without manifest; HTTP/ws proxy lives in railties	🔶
`config/vite.json`, custom tag options, `skip_proxy`/`auto_build`	✅	Not supported; `type:` is a String, not a Symbol	❌ (equivalent: class-level `ViteRuby::Manifest` properties + env vars)

Deviations & Crystal-specific notes

Locals are a Crystal literal: locals: {"post" => post} (a Ruby-style {post: post} is a NamedTuple in Crystal).
Partial local types are declared by the application in compile_partials (compile-time framework; Crystal does not allow Object in generics).
FormBuilder methods are a fixed set (in Rails they are also generated once by a CodeGenerator).
Templates are scanned and compiled at build time (CRAILS_VIEWS or app/views).

Testing

crystal spec

Oracle specs: oracle/cases.rb recorded against actionview 8.1.4 → oracle/expected.yml; the Vite layer is recorded against real vite_rails 3.0.19 / vite_ruby 3.9.2 (oracle/vite_cases.rb, oracle/vite_dev_cases.rb). Suite: 151 examples, 0 failures.

Repository

action_view.cr

Owner

OrelSokolov

Statistic

0
0
0
3
0
2 days ago
October 12, 2026

License

Links

Synced at

Mon, 12 Oct 2026 05:24:07 GMT

Languages

Crystal 78.79% Ruby 21.05% HTML 0.17%