Gecko [ beacons-mine.com ]

Name	Size	Permission	Date
capture	[ DIR ]	drwxr-xr-x	2026-02-18 15:11
api.rb	5.16 KB	-rw-r--r--	2025-08-20 20:06
around_block_scan.rb	6.9 KB	-rw-r--r--	2025-08-20 20:06
block_expand.rb	4.87 KB	-rw-r--r--	2025-08-20 20:06
capture_code_context.rb	6.67 KB	-rw-r--r--	2025-08-20 20:06
clean_document.rb	8.74 KB	-rw-r--r--	2025-08-20 20:06
cli.rb	3.12 KB	-rw-r--r--	2025-08-20 20:06
code_block.rb	2.13 KB	-rw-r--r--	2025-08-20 20:06
code_frontier.rb	5.62 KB	-rw-r--r--	2025-08-20 20:06
code_line.rb	6.46 KB	-rw-r--r--	2025-08-20 20:06
code_search.rb	3.82 KB	-rw-r--r--	2025-08-20 20:06
core_ext.rb	3 KB	-rw-r--r--	2025-08-20 20:06
display_code_with_line_numbers.rb	1.77 KB	-rw-r--r--	2025-08-20 20:06
display_invalid_blocks.rb	1.75 KB	-rw-r--r--	2025-08-20 20:06
explain_syntax.rb	2.41 KB	-rw-r--r--	2025-08-20 20:06
left_right_lex_count.rb	4.06 KB	-rw-r--r--	2025-08-20 20:06
lex_all.rb	1.12 KB	-rw-r--r--	2025-08-20 20:06
lex_value.rb	1.5 KB	-rw-r--r--	2025-08-20 20:06
parse_blocks_from_indent_line.rb	1.5 KB	-rw-r--r--	2025-08-20 20:06
pathname_from_message.rb	1.42 KB	-rw-r--r--	2025-08-20 20:06
priority_engulf_queue.rb	1.26 KB	-rw-r--r--	2025-08-20 20:06
priority_queue.rb	2 KB	-rw-r--r--	2025-08-20 20:06
ripper_errors.rb	837 B	-rw-r--r--	2025-08-20 20:06
scan_history.rb	2.92 KB	-rw-r--r--	2025-08-20 20:06
unvisited_lines.rb	705 B	-rw-r--r--	2025-08-20 20:06
version.rb	76 B	-rw-r--r--	2025-08-20 20:06

Rename

# frozen_string_literal: true

require_relative "left_right_lex_count"

module SyntaxSuggest
  # Explains syntax errors based on their source
  #
  # example:
  #
  #   source = "def foo; puts 'lol'" # Note missing end
  #   explain ExplainSyntax.new(
  #     code_lines: CodeLine.from_source(source)
  #   ).call
  #   explain.errors.first
  #   # => "Unmatched keyword, missing `end' ?"
  #
  # When the error cannot be determined by lexical counting
  # then ripper is run against the input and the raw ripper
  # errors returned.
  #
  # Example:
  #
  #   source = "1 * " # Note missing a second number
  #   explain ExplainSyntax.new(
  #     code_lines: CodeLine.from_source(source)
  #   ).call
  #   explain.errors.first
  #   # => "syntax error, unexpected end-of-input"
  class ExplainSyntax
    INVERSE = {
      "{" => "}",
      "}" => "{",
      "[" => "]",
      "]" => "[",
      "(" => ")",
      ")" => "(",
      "|" => "|"
    }.freeze

def initialize(code_lines:)
      @code_lines = code_lines
      @left_right = LeftRightLexCount.new
      @missing = nil
    end

def call
      @code_lines.each do |line|
        line.lex.each do |lex|
          @left_right.count_lex(lex)
        end
      end

self
    end

# Returns an array of missing elements
    #
    # For example this:
    #
    #   ExplainSyntax.new(code_lines: lines).missing
    #   # => ["}"]
    #
    # Would indicate that the source is missing
    # a `}` character in the source code
    def missing
      @missing ||= @left_right.missing
    end

# Converts a missing string to
    # an human understandable explanation.
    #
    # Example:
    #
    #   explain.why("}")
    #   # => "Unmatched `{', missing `}' ?"
    #
    def why(miss)
      case miss
      when "keyword"
        "Unmatched `end', missing keyword (`do', `def`, `if`, etc.) ?"
      when "end"
        "Unmatched keyword, missing `end' ?"
      else
        inverse = INVERSE.fetch(miss) {
          raise "Unknown explain syntax char or key: #{miss.inspect}"
        }
        "Unmatched `#{inverse}', missing `#{miss}' ?"
      end
    end

# Returns an array of syntax error messages
    #
    # If no missing pairs are found it falls back
    # on the original ripper error messages
    def errors
      if missing.empty?
        return RipperErrors.new(@code_lines.map(&:original).join).call.errors
      end

missing.map { |miss| why(miss) }
    end
  end
end