[Formatting] Syntax issues with block capturing

[rdimartino]

There are several related examples of this (kind of weird) pattern using capture to extract part of a template as a string to be passed into another template:

1. capture with do ... end for block and curly braces for template variable

   Rails renders the template, but stree format raises a syntax error

   ERB-snippet

   <%= render 'shared/template', { greeting: capture do %>
       <p>This block is captured as a string object and is available to the template as `greeting`</p>
       <p>The date and time is <%= Time.now %></p>
   <% end } do %>
       <p>This content is displayed where the template `yield`s</p>
   <% end %>

   Actual formatting

   Error: syntax error, unexpected end-of-input, expecting '}'
   > 1 | <%= render 'shared/template', { greeting: capture do %>
       |                                              ^
     2 |     <p>This block is captured as a string object and is available to the template as `greeting`</p>
     3 |     <p>The date and time is <%= Time.now %></p>
     4 | <% end } do %>

2. capture with { ... } for block and curly braces for template variable

   Rails renders the template, but stree format raises a syntax error

   ERB-snippet

   <%= render 'shared/template', { greeting: capture { %>
       <p>This block is captured as a string object and is available to the template as `greeting`</p>
       <p>The date and time is <%= Time.now %></p>
   <% } } do %>
       <p>This content is displayed where the template `yield`s</p>
   <% end %>

   Actual formatting

   Syntax error, even though Rails renders

   Error: syntax error, unexpected end-of-input
   > 1 | <%= render 'shared/template', { greeting: capture { %>
       |                                                ^
     2 |     <p>This block is captured as a string object and is available to the template as `greeting`</p>
     3 |     <p>The date and time is <%= Time.now %></p>
     4 | <% } } do %>

3. capture with { ... } for block and no braces for template variable

   Rails renders the template, but stree format raises a syntax error

   ERB-snippet

   <%= render 'shared/template', greeting: capture { %>
       <p>This block is captured as a string object and is available to the template as `greeting`</p>
       <p>The date and time is <%= Time.now %></p>
   <% } do %>
       <p>This content is displayed where the template `yield`s</p>
   <% end %>

   Actual formatting

   Syntax error, even though Rails renders

   Error: syntax error, unexpected end-of-input
   > 1 | <%= render 'shared/template', greeting: capture { %>
       |                                              ^
     2 |     <p>This block is captured as a string object and is available to the template as `greeting`</p>
     3 |     <p>The date and time is <%= Time.now %></p>
     4 | <% } do %>

4. capture with do ... end for block and no braces for template variable

   The opposite issue. Rails raises a syntax error, but stree format formats successfully

   ERB-snippet

   <%= render 'shared/template', greeting: capture do %>
       <p>This block is captured as a string object and is available to the template as `greeting`</p>
       <p>The date and time is <%= Time.now %></p>
   <% end do %>
       <p>This content is displayed where the template `yield`s</p>
   <% end %>

   the Rails error is

   SyntaxError: /<path>/app/views/capture.html.erb:4: syntax error, unexpected `do', expecting `end'
   '.freeze; end do 
                 ^~
   /<path>/app/views/capture.html.erb:8: syntax error, unexpected `end', expecting end-of-input
             end
             ^~~

   Actual formatting

   "Successful" output of bundle exec stree format --plugins=erb app/views/capture.html.erb.

   <%= render "shared/template", greeting: capture do %>
     <p>This block is captured as a string object and is available to the template as `greeting`</p>
     <p>The date and time is <%= Time.now %></p>
   <% end do %>
   <p>This content is displayed where the template `yield`s</p>
   <% end %>

Expected formatting

Not 100% sure what the expected format should be, but I sort of like this:

<%= render 'shared/template', {
        greeting: capture do %>
            <p>This block is captured as a string object and is available to the template as `greeting`</p>
            <p>The date and time is <%= Time.now %></p>
        <% end
    } do %>
    <p>This content is displayed where the template `yield`s</p>
<% end %>

Comment

Had a couple examples of this in some legacy code I maintain. Also worth noting that this was hard to find at first because the syntax doesn't usually point to the correct location. It often (in my case) would point to line 3 even if the offending code was nowhere near there (e.g. around line 100+)

Versions

syntax_tree: 0.10.5
syntax_tree-erb: 6.1.1

[davidwessman]

Ah, have not added any handling for capture. Will investigate 🙂

Yeah, the error reference is hard - will see if I can make that better too.

Thanks for clear error reports 😊