class Kramdown::Utils::StringScanner
This patched StringScanner
adds line number information for current scan position and a start_line_number
override for nested StringScanners.
Attributes
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.
Public Class Methods
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 26 def initialize(string, start_line_number = 1) 27 super(string) 28 @start_line_number = start_line_number || 1 29 @previous_pos = 0 30 @previous_line_number = @start_line_number 31 end
Public Instance Methods
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 67 def current_line_number 68 # Not using string[@previous_pos..best_pos].count('\n') because it is slower 69 strscan = ::StringScanner.new(string) 70 strscan.pos = @previous_pos 71 old_pos = pos + 1 72 @previous_line_number += 1 while strscan.skip_until(/\n/) && strscan.pos <= old_pos 73 74 @previous_pos = (eos? ? pos : pos + 1) 75 @previous_line_number 76 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 37 def pos=(pos) 38 if self.pos > pos 39 @previous_line_number = @start_line_number 40 @previous_pos = 0 41 end 42 super 43 end
Revert the position to one saved by save_pos
.
# File lib/kramdown/utils/string_scanner.rb 56 def revert_pos(data) 57 self.pos = data[0] 58 @previous_pos, @previous_line_number = data[1], data[2] 59 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 51 def save_pos 52 [pos, @previous_pos, @previous_line_number] 53 end