ERB nodes currently lack access to Ruby AST semantics

[kozy4324]

Problem

Currently, ERB-related nodes in Herb are not associated with the corresponding Ruby AST nodes.

Limitation

Because of this, some analyses have to rely on inspecting Ruby source code as plain text:

herb/lib/herb/engine/debug_visitor.rb

Lines 316 to 345 in 5c92c3e

	# TODO: Rewrite using Prism Nodes once available
	def complex_rails_helper?(code)
	cleaned_code = code.strip.gsub(/\s+/, " ")
	return true if cleaned_code.match?(/\bturbo_frame_tag\s*[(\s]/)
	return true if cleaned_code.match?(/\blink_to\s.*\s+do\s*$/) ||
	cleaned_code.match?(/\blink_to\s.*\{\s*$/) ||
	cleaned_code.match?(/\blink_to\s.*\s+do\s*\|/) ||
	cleaned_code.match?(/\blink_to\s.*\{\s*\|/)
	return true if cleaned_code.match?(/\brender[\s(]/)
	return true if cleaned_code.match?(/\bform_with\s.*\s+do\s*[|$]/) ||
	cleaned_code.match?(/\bform_with\s.*\{\s*[|$]/)
	return true if cleaned_code.match?(/\bcontent_for\s.*\s+do\s*$/) ||
	cleaned_code.match?(/\bcontent_for\s.*\{\s*$/)
	return true if cleaned_code.match?(/\bcontent_tag\s.*\s+do\s*$/) ||
	cleaned_code.match?(/\bcontent_tag\s.*\{\s*$/)
	return true if cleaned_code.match?(/\bcontent_tag\(.*\s+do\s*$/) ||
	cleaned_code.match?(/\bcontent_tag\(.*\{\s*$/)
	return true if cleaned_code.match?(/\btag\.\w+\s.*do\s*$/) ||
	cleaned_code.match?(/\btag\.\w+\s.*\{\s*$/)
	false
	end

Proposal (proof of concept)

I explored a proof of concept where ERB nodes are associated with Ruby AST nodes using extract_ruby.

The idea is:

• Extract Ruby code from the ERB template via extract_ruby
• Parse it as a single Ruby program with Prism
• For each ERB node, find the Prism node whose source range falls within the ERB node’s range
• Attach that Prism node to the ERB node for downstream visitors

I implemented this in Ruby as a small prototype ( PrismAstVisitor ) to validate the direction.
I’m aware that a real implementation would likely belong in the C layer; this experiment is purely to confirm feasibility and design direction.

https://gist.github.com/kozy4324/fd7f6542d77c273960ef8b96848cce32

Question

Does this direction align with your thinking?
If you already have a plan for this problem space, I’d love to hear it.
I’d also be happy to contribute if there’s something I can help with.