StringScanner adds line number information for current scan position and a
start_line_number override for nested StringScanners.
The start line number. Used for nested StringScanners that scan a sub-string of the source document. The kramdown parser uses this, e.g., for span level parsers.
Takes the start line number as optional second argument.
Note: The original second argument is no longer used so this should be safe.
# File lib/kramdown/utils/string_scanner.rb, line 25 def initialize(string, start_line_number = 1) super(string) @start_line_number = start_line_number || 1 @previous_pos = 0 @previous_line_number = @start_line_number end
Returns the line number for current charpos.
NOTE: Requires that all line endings are normalized to 'n'
NOTE: Normally we'd have to add one to the count of newlines to get the correct line number. However we add the one indirectly by using a one-based start_line_number.
# File lib/kramdown/utils/string_scanner.rb, line 66 def current_line_number # Not using string[@previous_pos..best_pos].count('\n') because it is slower strscan = ::StringScanner.new(string) strscan.pos = @previous_pos old_pos = pos + 1 @previous_line_number += 1 while strscan.skip_until(/\n/) && strscan.pos <= old_pos @previous_pos = (eos? ? pos : pos + 1) @previous_line_number end
Sets the byte position of the scan pointer.
Note: This also resets some internal variables, so always use pos= when setting the position and don't use any other method for that!
# File lib/kramdown/utils/string_scanner.rb, line 36 def pos=(pos) if self.pos > pos @previous_line_number = @start_line_number @previous_pos = 0 end super end
Revert the position to one saved by
# File lib/kramdown/utils/string_scanner.rb, line 55 def revert_pos(data) self.pos = data @previous_pos, @previous_line_number = data, data end
Return information needed to revert the byte position of the string scanner in a performant way.
The returned data can be fed to
revert_pos to revert the position to the saved one.
Note: Just saving pos won't be enough.
# File lib/kramdown/utils/string_scanner.rb, line 50 def save_pos [pos, @previous_pos, @previous_line_number] end