Module: Coradoc::AsciiDoc::Parser::BlockHeader

Included in:
Base
Defined in:
lib/coradoc/asciidoc/parser/block_header.rb

Overview

Single Responsibility: parse the optional header that precedes a structural element (block or section).

Encapsulates the canonical AsciiDoc header grammar in one place (DRY, MECE, single source of truth). Two flavours live here because blocks and sections have different header grammars:

block_header   = block_title? >> element_id? >> attribute_blocks?
section_header =                    element_id? >> attribute_blocks?

Asciidoctor does NOT permit .Title to apply to a section — sections accept [role] attribute lists and [[id]] anchors but not block titles. The section's heading IS its title. Mixing the two shapes into one rule caused section_block to admit .Foo lines that collided with section_title's :title capture, triggering Parslet's "Duplicate subtrees while merging result … (keys: [:title])" warning and silently dropping the block title.

Before this module existed, every block-like rule inlined its own header rule with subtly different slot orderings — and several captured the same Parslet key more than once in a single sequence, which triggered Parslet's "Duplicate subtrees" warning and silently discarded one of the captured values.

attribute_blocks accepts one or more consecutive [...] attribute lists, captured as a Parslet sequence under the :attribute_list key. Real-world AsciiDoc often stacks attribute lists before a block:

[role=quote] [source, ruby]

code

Capturing the sequence (rather than one slot per [...]) preserves every attribute and lets the transformer merge them into a single Coradoc::AsciiDoc::Model::AttributeList downstream.

Instance Method Summary collapse

Instance Method Details

#attribute_blocks ⇒ Parslet::Atoms::Base

One or more consecutive attribute_list + newline sequences, captured as a Parslet sequence under :attribute_list. When multiple [...] blocks precede a delimiter, all of them reach the transformer; when only one appears, the sequence has a single element and the existing transformer rule handles it the same way as before.

Returns:

  • (Parslet::Atoms::Base) 


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# File 'lib/coradoc/asciidoc/parser/block_header.rb', line 72

def attribute_blocks
  (attribute_list >> newline).repeat(1).as(:attribute_list)
end

#block_header ⇒ Parslet::Atoms::Base

Canonical block header rule. Includes the block title — every real block (delimited block, table, paragraph, image) accepts an optional .Title line before its body. Single canonical order; each of title, id, and attribute_blocks is optional and matched at most once.

Returns:

  • (Parslet::Atoms::Base) 


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# File 'lib/coradoc/asciidoc/parser/block_header.rb', line 50

def block_header
  block_title.maybe >>
    element_id.maybe >>
    attribute_blocks.maybe
end

#section_header ⇒ Parslet::Atoms::Base

Section header rule. Asciidoctor does not permit .Title on sections — the section heading itself is the title. Sections still accept the same element_id and attribute_blocks slots that blocks do ([[anchor]], [appendix], [role=x], etc.).

Returns:

  • (Parslet::Atoms::Base) 


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# File 'lib/coradoc/asciidoc/parser/block_header.rb', line 61

def section_header
  element_id.maybe >>
    attribute_blocks.maybe
end