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Diffstat (limited to 'lib/syntax_suggest/capture_code_context.rb')
| -rw-r--r-- | lib/syntax_suggest/capture_code_context.rb | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/lib/syntax_suggest/capture_code_context.rb b/lib/syntax_suggest/capture_code_context.rb new file mode 100644 index 0000000000..c74a366a25 --- /dev/null +++ b/lib/syntax_suggest/capture_code_context.rb @@ -0,0 +1,233 @@ +# frozen_string_literal: true + +module SyntaxSuggest + # Turns a "invalid block(s)" into useful context + # + # There are three main phases in the algorithm: + # + # 1. Sanitize/format input source + # 2. Search for invalid blocks + # 3. Format invalid blocks into something meaninful + # + # This class handles the third part. + # + # The algorithm is very good at capturing all of a syntax + # error in a single block in number 2, however the results + # can contain ambiguities. Humans are good at pattern matching + # and filtering and can mentally remove extraneous data, but + # they can't add extra data that's not present. + # + # In the case of known ambiguious cases, this class adds context + # back to the ambiguitiy so the programmer has full information. + # + # Beyond handling these ambiguities, it also captures surrounding + # code context information: + # + # puts block.to_s # => "def bark" + # + # context = CaptureCodeContext.new( + # blocks: block, + # code_lines: code_lines + # ) + # + # lines = context.call.map(&:original) + # puts lines.join + # # => + # class Dog + # def bark + # end + # + class CaptureCodeContext + attr_reader :code_lines + + def initialize(blocks:, code_lines:) + @blocks = Array(blocks) + @code_lines = code_lines + @visible_lines = @blocks.map(&:visible_lines).flatten + @lines_to_output = @visible_lines.dup + end + + def call + @blocks.each do |block| + capture_first_kw_end_same_indent(block) + capture_last_end_same_indent(block) + capture_before_after_kws(block) + capture_falling_indent(block) + end + + @lines_to_output.select!(&:not_empty?) + @lines_to_output.uniq! + @lines_to_output.sort! + + @lines_to_output + end + + # Shows the context around code provided by "falling" indentation + # + # Converts: + # + # it "foo" do + # + # into: + # + # class OH + # def hello + # it "foo" do + # end + # end + # + # + def capture_falling_indent(block) + AroundBlockScan.new( + block: block, + code_lines: @code_lines + ).on_falling_indent do |line| + @lines_to_output << line + end + end + + # Shows surrounding kw/end pairs + # + # The purpose of showing these extra pairs is due to cases + # of ambiguity when only one visible line is matched. + # + # For example: + # + # 1 class Dog + # 2 def bark + # 4 def eat + # 5 end + # 6 end + # + # In this case either line 2 could be missing an `end` or + # line 4 was an extra line added by mistake (it happens). + # + # When we detect the above problem it shows the issue + # as only being on line 2 + # + # 2 def bark + # + # Showing "neighbor" keyword pairs gives extra context: + # + # 2 def bark + # 4 def eat + # 5 end + # + def capture_before_after_kws(block) + return unless block.visible_lines.count == 1 + + around_lines = AroundBlockScan.new(code_lines: @code_lines, block: block) + .start_at_next_line + .capture_neighbor_context + + around_lines -= block.lines + + @lines_to_output.concat(around_lines) + end + + # When there is an invalid block with a keyword + # missing an end right before another end, + # it is unclear where which keyword is missing the + # end + # + # Take this example: + # + # class Dog # 1 + # def bark # 2 + # puts "woof" # 3 + # end # 4 + # + # However due to https://github.com/zombocom/syntax_suggest/issues/32 + # the problem line will be identified as: + # + # ❯ class Dog # 1 + # + # Because lines 2, 3, and 4 are technically valid code and are expanded + # first, deemed valid, and hidden. We need to un-hide the matching end + # line 4. Also work backwards and if there's a mis-matched keyword, show it + # too + def capture_last_end_same_indent(block) + return if block.visible_lines.length != 1 + return unless block.visible_lines.first.is_kw? + + visible_line = block.visible_lines.first + lines = @code_lines[visible_line.index..block.lines.last.index] + + # Find first end with same indent + # (this would return line 4) + # + # end # 4 + matching_end = lines.detect { |line| line.indent == block.current_indent && line.is_end? } + return unless matching_end + + @lines_to_output << matching_end + + # Work backwards from the end to + # see if there are mis-matched + # keyword/end pairs + # + # Return the first mis-matched keyword + # this would find line 2 + # + # def bark # 2 + # puts "woof" # 3 + # end # 4 + end_count = 0 + kw_count = 0 + kw_line = @code_lines[visible_line.index..matching_end.index].reverse.detect do |line| + end_count += 1 if line.is_end? + kw_count += 1 if line.is_kw? + + !kw_count.zero? && kw_count >= end_count + end + return unless kw_line + @lines_to_output << kw_line + end + + # The logical inverse of `capture_last_end_same_indent` + # + # When there is an invalid block with an `end` + # missing a keyword right after another `end`, + # it is unclear where which end is missing the + # keyword. + # + # Take this example: + # + # class Dog # 1 + # puts "woof" # 2 + # end # 3 + # end # 4 + # + # the problem line will be identified as: + # + # ❯ end # 4 + # + # This happens because lines 1, 2, and 3 are technically valid code and are expanded + # first, deemed valid, and hidden. We need to un-hide the matching keyword on + # line 1. Also work backwards and if there's a mis-matched end, show it + # too + def capture_first_kw_end_same_indent(block) + return if block.visible_lines.length != 1 + return unless block.visible_lines.first.is_end? + + visible_line = block.visible_lines.first + lines = @code_lines[block.lines.first.index..visible_line.index] + matching_kw = lines.reverse.detect { |line| line.indent == block.current_indent && line.is_kw? } + return unless matching_kw + + @lines_to_output << matching_kw + + kw_count = 0 + end_count = 0 + orphan_end = @code_lines[matching_kw.index..visible_line.index].detect do |line| + kw_count += 1 if line.is_kw? + end_count += 1 if line.is_end? + + end_count >= kw_count + end + + return unless orphan_end + @lines_to_output << orphan_end + end + end +end |