Stimulus: Feature Request: Nicer syntax for action descriptors

[thiagomajesk]

Hi guys! First of all, I'd like to know if this is on the roadmap or if it's up for debate.
If the latter, I'd like to suggest the syntax: click::hello.greet or click::hello@greet.
IMHO current syntax is a bit rough on the eyes (not to say ugly) 😁.

[luikore]

I think current syntax is better...

However, if you use slim, I have a monkey patch to clean the "data-*" attributes so the template will look like this:

/ hello.slim
div @controller="hello"
  input type="text" @target="hello.name"
  button @click="hello#greet" Greet
  span @target="hello.output"

The following patch to slim parser just matches HTML attributes starting with @ and do transforms:

# test.rb
require 'slim'

module Slim
  class Parser
    def parse_attributes(attributes)
      # Check to see if there is a delimiter right after the tag name
      delimiter = nil
      if @line =~ @attr_list_delims_re
        delimiter = @attr_list_delims[$1]
        @line = $'
      end

      if delimiter
        boolean_attr_re = /#{@attr_name}(?=(\s|#{Regexp.escape delimiter}|\Z))/
        end_re = /\A\s*#{Regexp.escape delimiter}/
      end

      while true
        case @line
        when @splat_attrs_regexp
          # Splat attribute
          @line = $'
          attributes << [:slim, :splat, parse_ruby_code(delimiter)]

        when /\A\s*@(\w+)\s*=\s*(["'])([\w\.\-\>\#]+)\2/
          attr_value = $3
          if attr_value['#']
            @line = $'
            attr_value = "#$1->#{attr_value}"
            attributes << [:html, :attr, 'data-action', [:slim, :interpolate, attr_value]]
          else
            case $1
            when 'controller'
              @line = $'
              attributes << [:html, :attr, 'data-controller', [:slim, :interpolate, attr_value]]
            when 'target'
              @line = $'
              attributes << [:html, :attr, 'data-target', [:slim, :interpolate, attr_value]]
            else
              syntax_error!('Must use "@controller=" or "@target=" or assign "controller#action"')
            end
          end

        when @quoted_attr_re
          # Value is quoted (static)
          @line = $'
          attributes << [:html, :attr, $1,
                         [:escape, $2.empty?, [:slim, :interpolate, parse_quoted_attribute($3)]]]
        when @code_attr_re
          # Value is ruby code
          @line = $'
          name = $1
          escape = $2.empty?
          value = parse_ruby_code(delimiter)
          syntax_error!('Invalid empty attribute') if value.empty?
          attributes << [:html, :attr, name, [:slim, :attrvalue, escape, value]]

        else
          break unless delimiter

          case @line
          when boolean_attr_re
            # Boolean attribute
            @line = $'
            attributes << [:html, :attr, $1, [:multi]]
          when end_re
            # Find ending delimiter
            @line = $'
            break
          else
            # Found something where an attribute should be
            @line.lstrip!
            syntax_error!('Expected attribute') unless @line.empty?

            # Attributes span multiple lines
            @stacks.last << [:newline]
            syntax_error!("Expected closing delimiter #{delimiter}") if @lines.empty?
            next_line
          end
        end
      end
    end
  end
end

puts Slim::Template.new('hello.slim').render binding

Then it generates:

<div data-controller="hello">
  <input data-target="hello.name" type="text" />
  <button data-action="click->hello#greet">Greet</button>
  <span data-target="hello.output"></span>
</div>

[thiagomajesk]

@luikore I'm not refering to the syntax for the data attributes per se. I'm talking about the "template" for defining event->controller#action. Maybe for people who use rails it's a little bit more natural (because of the route templates).

[savroff]

I think it's more about who likes what more. Changes will not affect functionality or a learning curve.
But will create more work to migrate to the next version.

[dhh]

No plans to change the syntax, beyond exploring places where you can use action and target naming without explicitly referring to the controlled scope, when that can be done unambiguously.