Transform multi-line ERB Comment to multi-line Ruby comment when extracting Ruby code in herb_extract_ruby
#102
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enhancement
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marcoroth
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herb_extract_rubyherb_extract_ruby
marcoroth
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May 3, 2025
This pull request updates the `herb_extract_ruby` and
`herb_extract_ruby_to_buffer_with_semicolons` methods in `extract.c` to
not extract the content of ERB Comment Nodes (`<%#`) as Ruby code.
So a source file like this:
```html+erb
<%# This is a comment %>
<h1><%= title %></h1>
```
Was extracted to Ruby code as:
```ruby
# This is a comment
title
```
With the changes included in this pull request it's going to be:
```ruby
title
```
This is in order to resolve #91. It's valid to have multi-line ERB
Comments like:
```html+erb
<%#
This is
a comment
over multiple
lines
%>
```
Which before this pull request was extracted to Ruby as:
```ruby
#
This is
a comment
over multiple
lines
```
Which is not a valid Ruby comment anymore, but treated as actual Ruby
code from the second line on. If the comment itself included Ruby
keywords it would cause syntax errors.
For now, we don't extract the ERB Comments at all - which is the change
this pull request introduces.
In the future, we can implement #100 (and/or #102) and also make sure
that multi-line ERB Comments get extracted to multi-line Ruby Comments,
like:
```ruby
# This is
# a comment
# over multiple
# lines
```
or maybe even cleverer: replace the `<%` with a `=begin` and the `%>`
with a `=end`:
```ruby
=begin
This is
a comment
over multiple
lines
=end
```
Another case where it would break Ruby syntax is in this example:
```html+erb
<% if true %><%# Comment here %><% end %>
```
Which is going to comment out the `end` as well:
```ruby
if true # Comment here end
```
This use-case is also fixed with this pull request, since we just skip
over the ERB Comments content:
```ruby
if true end
```
This last example could be solved even more elegantly if Ruby shipped
the Inline Comments feature:
https://bugs.ruby-lang.org/issues/20405
This following example is still broken and this pull request does not
address that use-case. I opened #101 for this.
```html+erb
<% if true %><% # Comment here %><% end %>
```
Currently it does not address the case, where the comment is part of the
Ruby Code itself, so the comment is not seen as a "ERB Comment Node":
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In #98 we skipped the extract of ERB Comments when extracting Ruby code, but ideally we would also convert the ERB comment to Ruby comments in all cases.
Given this source:
We would want it to extract the following Ruby code:
and/or:
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