PoParser::Scanner

Returns true if the stream is at the beginning of a line and not at EOS.

Returns the value that #scan would return, without advancing the scan offset. The last match is still saved, however.

require "string_scanner"

s = StringScanner.new("this is a string")
s.offset = 5
s.check(/\w+/) # => "is"
s.check(/\w+/) # => "is"

Returns the character at the scan head, and errors if at the end. Does not move the scan head. This will properly decode the next character from the string, and may return a multi-byte character.

Returns the character at the scan head, or nil if at the end. Does not move the scan head. This will properly decode the next character from the string, and may return a multi-byte character.

Rewinds the scan head by len characters.

Raises IndexError if this would go off the beginning of the stream.

Advances the offset by len chars, and returns a string of that length.

NOTE: If there are less than the requested number of characters remaining in the string, this method will return nil and not advance the scan head. To obtain the entire rest of the input string, use #rest.

require "string_scanner"

s = StringScanner.new("あいうえお")
s.scan(3)   # => "あいう"
s.scan(100) # => nil
s.scan(2)   # => "えお"
s.scan(0)   # => ""

Tries to match with pattern at the current position. If there's a match, the scanner advances the scan offset, the last match is saved, and it returns the matched string. Otherwise, the scanner returns nil.

require "string_scanner"

s = StringScanner.new("test string")
s.scan(/\w+/)  # => "test"
s.scan(/\w+/)  # => nil
s.scan(/\s\w/) # => " s"
s.scan('t')    # => "t"
s.scan("ring") # => "ring"
s.scan(/.*/)   # => ""

Advances the offset by len chars.

Prefer this to scanner.offset += len, since that can cause a full scan of the string in the case of multibyte characters.

NOTE: If there are less than the requested number of characters remaining in the string, this method will return nil and not advance the scan head. To move the scan head to the very end, use #terminate.

Attempts to skip over the given pattern beginning with the scan offset.

If there's a match, the scanner advances the scan offset, the last match is saved, and it returns the size of the skipped match. Otherwise it returns nil and does not advance the offset.

This method is the same as #scan, but without returning the matched string.