Take equal portions of Mike Stok and Sean Russell; mix vigorously, and pour
into a tall, chilled glass. Serves 10,000.
# File lib/rexml/functions.rb, line 231
def Functions::substring( string, start, length=nil )
ruby_string = string(string)
ruby_length = if length.nil?
ruby_string.length.to_f
else
number(length)
end
ruby_start = number(start)
# Handle the special cases
return '' if (
ruby_length.nan? or
ruby_start.nan? or
ruby_start.infinite?
)
infinite_length = ruby_length.infinite? == 1
ruby_length = ruby_string.length if infinite_length
# Now, get the bounds. The XPath bounds are 1..length; the ruby bounds
# are 0..length. Therefore, we have to offset the bounds by one.
ruby_start = round(ruby_start) - 1
ruby_length = round(ruby_length)
if ruby_start < 0
ruby_length += ruby_start unless infinite_length
ruby_start = 0
end
return '' if ruby_length <= 0
ruby_string[ruby_start,ruby_length]
end