Class: TableExtractor

Inherits:
Object show all
Defined in:
lib/table_extractor.rb

Overview

Extracts Markdown-style tables from text lines and returns metadata about each table

This class analyzes an array of text lines to identify tables formatted in Markdown style. It supports both multi-line tables (using | delimiters) and single-line tables (using ! delimiters). For each table found, it returns metadata including row count, column count, and position.

Examples:

lines = [
  '| Name | Age | City',
  '|------|-----|-----',
  '| John | 30  | NYC'
]
tables = TableExtractor.extract_tables(lines, regexp: /^[ \t]*\|? *(?::?-+:?) *( *\| *(?::?-+:?) *)*\|? *$/)
# Returns: [{ column_offset: 1, columns: 3, delimiter: '|', rows: 3, start_index: 0 }]

Class Method Summary collapse

Class Method Details

.extract_tables(lines, multi_line_delimiter: '|', regexp:, single_line_delimiter: '!') ⇒ Array<Hash>

Extract tables from an array of text lines formatted in Markdown style

Parameters:

  • lines (Array<String>) —

    The array of text lines to analyze

  • regexp (Regexp) —

    Regular expression to match table separator rows (e.g., |—|—|)

  • multi_line_delimiter (String) (defaults to: '|') —

    Delimiter character for multi-line tables (default: ‘|’)

  • single_line_delimiter (String) (defaults to: '!') —

    Delimiter character for single-line tables (default: ‘!’)

Returns:

  • (Array<Hash>) —

    Array of table metadata hashes with keys:

    • column_offset: Always 1 (for compatibility)

    • columns: Number of columns in the table

    • delimiter: The delimiter character used (‘|’ or ‘!’)

    • rows: Number of rows in the table

    • start_index: Index of the first line of the table in the input array



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# File 'lib/table_extractor.rb', line 30

def self.extract_tables(
  lines,
  multi_line_delimiter: '|',
  regexp:,
  single_line_delimiter: '!'
)
  current_column_count = 0
  current_row_count = 0
  extracted_tables = []
  inside_multi_line_table = false
  table_start_index = nil

  # Regex patterns for single-line table row parsing
  single_line_start_pattern = /^\s*#{single_line_delimiter}/
  single_line_content_pattern = /(?:^|(?<=#{single_line_delimiter}))\s*([^#{single_line_delimiter}]*)\s*(?=#{single_line_delimiter}|$)/

  # Helper method to add the current table to results and reset state
  add_current_table = lambda do |delimiter|
    extracted_tables << {
      column_offset: 1,
      columns: current_column_count,
      delimiter: delimiter,
      rows: current_row_count,
      start_index: table_start_index
    }
    current_column_count = 0
    current_row_count = 0
    inside_multi_line_table = false
    table_start_index = nil
  end

  lines.each_with_index do |line, line_index|
    # Detect single-line tables (e.g., !Name!Age!City!)
    if !inside_multi_line_table && line =~ single_line_start_pattern
      current_row_count = 1
      extracted_columns = line.scan(single_line_content_pattern).flatten
      table_start_index = line_index

      current_column_count = extracted_columns.count - 1
      add_current_table.call(single_line_delimiter)

    # Detect multi-line table separator rows (e.g., |---|---|)
    elsif line.strip.match?(regexp)
      if inside_multi_line_table
        # Add the current table before starting a new one
        add_current_table.call(multi_line_delimiter)
      end
      # Start a new multi-line table
      current_column_count = line.split(multi_line_delimiter).count - 1
      current_row_count = 2 # Account for header and separator rows
      inside_multi_line_table = true
      table_start_index = line_index - 1 if table_start_index.nil?

    # Continue multi-line table with data rows
    elsif inside_multi_line_table &&
          (line.strip.start_with?(multi_line_delimiter) ||
           line.include?(multi_line_delimiter))
      current_row_count += 1

    # End multi-line table when we encounter a non-table line
    elsif inside_multi_line_table
      add_current_table.call(multi_line_delimiter)
    end
  end

  # Handle table that ends at the last line
  if inside_multi_line_table
    add_current_table.call(multi_line_delimiter)
  end

  extracted_tables
end