Module: Oselvar::Var::Core::Scanner

Defined in:
lib/oselvar/var/core/scanner.rb

Overview

Markdown block scanner. Port of scanner.ts. All offsets count UTF-16 code units; split_lines advances by utf16_len(line) + 1 per newline, and code-point indices from String#index are converted to UTF-16 before use.

Defined Under Namespace

Classes: RawLine

Constant Summary collapse

THEMATIC_RE =

Regexes — verbatim ports of the TS constants (# escaped as \# so Ruby does not read #{...} as interpolation).

/^\s*([-*_])(\s*\1){2,}\s*$/
UL_RE = 
/^(\s*)([-*+])\s+(.*)$/
OL_RE = 
/^(\s*)(\d+)([.)])\s+(.*)$/
BQ_RE = 
/^>\s?(.*)$/
FENCE_RE = 
/^(`{3,})\s*(\S*)\s*$/
ROW_RE = 
/^\|(.+)\|\s*$/
DELIM_RE = 
/^\|\s*:?-+:?\s*(\|\s*:?-+:?\s*)*\|\s*$/
HEADING_RE = 
/^(\#{1,6})\s+(.*?)(?:\s+\#+)?\s*$/
PARA_HEADING_RE = 
/^\#{1,6}\s+/

Class Method Summary collapse

Class Method Details

.consume_paragraph(source, lines, start_idx, plugins) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 227

def consume_paragraph(source, lines, start_idx, plugins)
  raise 'invariant: start_idx out of range' if start_idx >= lines.length

  first = lines[start_idx]
  end_idx = start_idx
  while end_idx + 1 < lines.length
    candidate_idx = end_idx + 1
    candidate = lines[candidate_idx]
    break if candidate.text.strip.empty?
    break if PARA_HEADING_RE.match?(candidate.text)
    break if UL_RE.match?(candidate.text)
    break if OL_RE.match?(candidate.text)
    break if BQ_RE.match?(candidate.text)
    break if FENCE_RE.match?(candidate.text)
    break if ROW_RE.match?(candidate.text)
    break if THEMATIC_RE.match?(candidate.text)
    break if run_plugins(source, lines, candidate_idx, plugins)

    end_idx += 1
  end

  last = lines[end_idx]
  start_offset = first.start_offset
  end_offset = last.end_offset
  [
    Paragraph.new(
      text: Offsets.utf16_slice(source, start_offset, end_offset),
      span: Offsets.span_from_offsets(source, start_offset, end_offset),
      segment_map: [SegmentOffset.new(text_offset: 0, source_offset: start_offset)]
    ),
    end_idx + 1
  ]
end

.run_plugins(source, lines, start_idx, plugins) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 100

def run_plugins(source, lines, start_idx, plugins)
  plugins.each do |p|
    r = p.try_scan(source: source, lines: lines, start_idx: start_idx)
    return r if r
  end
  nil
end

.scan(source, plugins = []) ⇒ Object

Scan source into an immutable Array of Block nodes.



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# File 'lib/oselvar/var/core/scanner.rb', line 31

def scan(source, plugins = [])
  blocks = []
  lines = split_lines(source)

  i = 0
  while i < lines.length
    line = lines[i]
    if line.text.strip.empty?
      i += 1
      next
    end

    matched = run_plugins(source, lines, i, plugins)
    if matched
      blocks << matched[0]
      i = matched[1]
      next
    end

    fence_result = try_fence(source, lines, i)
    if fence_result
      blocks << fence_result[0]
      i = fence_result[1]
      next
    end

    table_result = try_table(source, lines, i)
    if table_result
      blocks << table_result[0]
      i = table_result[1]
      next
    end

    thematic = try_thematic(source, line)
    if thematic
      blocks << thematic
      i += 1
      next
    end

    bq_result = try_blockquote(source, lines, i)
    if bq_result
      blocks << bq_result[0]
      i = bq_result[1]
      next
    end

    heading = try_heading(source, line)
    if heading
      blocks << heading
      i += 1
      next
    end

    list_item = try_list_item(source, line)
    if list_item
      blocks << list_item
      i += 1
      next
    end

    paragraph, next_i = consume_paragraph(source, lines, i, plugins)
    blocks << paragraph
    i = next_i
  end

  blocks
end

.split_lines(source) ⇒ Object

Split source into RawLines with UTF-16 start/end offsets.



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# File 'lib/oselvar/var/core/scanner.rb', line 109

def split_lines(source)
  out = []
  start_u16 = 0
  current_u16 = 0
  start_cp = 0

  source.each_char.with_index do |ch, cp_i|
    if ch == "\n"
      out << RawLine.new(text: source[start_cp...cp_i], start_offset: start_u16, end_offset: current_u16)
      start_u16 = current_u16 + 1 # '\n' is BMP → 1 UTF-16 unit
      start_cp = cp_i + 1
    end
    current_u16 += ch.ord > 0xFFFF ? 2 : 1
  end

  out << RawLine.new(text: source[start_cp..] || '', start_offset: start_u16, end_offset: current_u16)
  out
end

.try_blockquote(source, lines, start_idx) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 179

def try_blockquote(source, lines, start_idx)
  return nil if start_idx >= lines.length

  first = lines[start_idx]
  m = BQ_RE.match(first.text)
  return nil unless m

  first_segment = m[1] || ''
  cp_idx = first.text.index(first_segment)
  segments = [first_segment]
  segment_map = [
    SegmentOffset.new(
      text_offset: 0,
      source_offset: first.start_offset + Offsets.to_utf16_offset(first.text, cp_idx)
    )
  ]
  joined_text_offset = Offsets.utf16_len(first_segment)

  i = start_idx + 1
  end_offset = first.end_offset
  while i < lines.length
    ln = lines[i]
    next_m = BQ_RE.match(ln.text)
    break unless next_m

    segment = next_m[1] || ''
    cp_idx2 = ln.text.index(segment)
    joined_text_offset += 1 # newline separator
    segment_map << SegmentOffset.new(
      text_offset: joined_text_offset,
      source_offset: ln.start_offset + Offsets.to_utf16_offset(ln.text, cp_idx2)
    )
    segments << segment
    joined_text_offset += Offsets.utf16_len(segment)
    end_offset = ln.end_offset
    i += 1
  end

  [
    Blockquote.new(
      text: segments.join("\n"),
      span: Offsets.span_from_offsets(source, first.start_offset, end_offset),
      segment_map: segment_map
    ),
    i
  ]
end

.try_fence(source, lines, start_idx) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 261

def try_fence(source, lines, start_idx)
  return nil if start_idx >= lines.length

  start = lines[start_idx]
  open_m = FENCE_RE.match(start.text)
  return nil unless open_m

  fence_marker = open_m[1] || ''
  info = (open_m[2] || '').strip

  i = start_idx + 1
  body_start = nil
  body_end = nil
  end_offset = start.end_offset

  while i < lines.length
    ln = lines[i]
    close_m = FENCE_RE.match(ln.text)
    if close_m && (close_m[1] || '').length >= fence_marker.length
      end_offset = ln.end_offset
      break
    end
    body_start = ln.start_offset if body_start.nil?
    body_end = ln.end_offset + 1 # +1 to include the '\n' after this line
    i += 1
  end

  body = body_start.nil? || body_end.nil? ? '' : Offsets.utf16_slice(source, body_start, body_end)

  fallback = start.end_offset
  body_span = Offsets.span_from_offsets(source, body_start || fallback, body_end || fallback)
  [
    Fence.new(
      info: info,
      body: body,
      body_span: body_span,
      span: Offsets.span_from_offsets(source, start.start_offset, end_offset)
    ),
    i + 1
  ]
end

.try_heading(source, line) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 134

def try_heading(source, line)
  m = HEADING_RE.match(line.text)
  return nil unless m

  Heading.new(
    level: m[1].length,
    text: (m[2] || '').strip,
    span: Offsets.span_from_offsets(source, line.start_offset, line.end_offset)
  )
end

.try_list_item(source, line) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 145

def try_list_item(source, line)
  if (ul = UL_RE.match(line.text))
    text = ul[3] || ''
    marker_start = line.start_offset + Offsets.utf16_len(ul[1] || '')
    marker_end = marker_start + Offsets.utf16_len(ul[2] || '')
    cp_idx = line.text.index(text)
    text_start = line.start_offset + Offsets.to_utf16_offset(line.text, cp_idx)
    return ListItem.new(
      text: text,
      span: Offsets.span_from_offsets(source, line.start_offset, line.end_offset),
      segment_map: [SegmentOffset.new(text_offset: 0, source_offset: text_start)],
      ordered: false,
      marker_span: Offsets.span_from_offsets(source, marker_start, marker_end)
    )
  end

  if (ol = OL_RE.match(line.text))
    text = ol[4] || ''
    marker_start = line.start_offset + Offsets.utf16_len(ol[1] || '')
    marker_end = marker_start + Offsets.utf16_len(ol[2] || '') + Offsets.utf16_len(ol[3] || '')
    cp_idx = line.text.index(text)
    text_start = line.start_offset + Offsets.to_utf16_offset(line.text, cp_idx)
    return ListItem.new(
      text: text,
      span: Offsets.span_from_offsets(source, line.start_offset, line.end_offset),
      segment_map: [SegmentOffset.new(text_offset: 0, source_offset: text_start)],
      ordered: true,
      marker_span: Offsets.span_from_offsets(source, marker_start, marker_end)
    )
  end

  nil
end

.try_table(source, lines, start_idx) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 303

def try_table(source, lines, start_idx)
  return nil if start_idx + 1 >= lines.length

  header_line = lines[start_idx]
  delim_line = lines[start_idx + 1]
  return nil unless ROW_RE.match?(header_line.text)
  return nil unless DELIM_RE.match?(delim_line.text)

  header_cells, header_cell_spans = TableCells.parse_row_cells(header_line.text, header_line.start_offset,
                                                               source)
  header = Row.new(
    cells: header_cells,
    cell_spans: header_cell_spans,
    span: Offsets.span_from_offsets(source, header_line.start_offset, header_line.end_offset)
  )

  rows = []
  i = start_idx + 2
  while i < lines.length
    ln = lines[i]
    break unless ROW_RE.match?(ln.text)

    cells, cell_spans = TableCells.parse_row_cells(ln.text, ln.start_offset, source)
    rows << Row.new(
      cells: cells,
      cell_spans: cell_spans,
      span: Offsets.span_from_offsets(source, ln.start_offset, ln.end_offset)
    )
    i += 1
  end

  last_row = rows.last
  end_offset = last_row ? last_row.span.end_offset : delim_line.end_offset
  [
    Table.new(
      span: Offsets.span_from_offsets(source, header_line.start_offset, end_offset),
      header: header,
      rows: rows
    ),
    i
  ]
end

.try_thematic(source, line) ⇒ Object 



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# File 'lib/oselvar/var/core/scanner.rb', line 128

def try_thematic(source, line)
  return nil unless THEMATIC_RE.match?(line.text)

  ThematicBreak.new(span: Offsets.span_from_offsets(source, line.start_offset, line.end_offset))
end