psych parses ":"-delimited time strings differently than syck

I'm not sure if this is a bug or changed behavior, perhaps I could get some clarification or resolution via this issue:

colon-delimited strings of integers are parsed by YAML into integer number of seconds. it appears that the psych engine treats the last unit as minutes, whereas syck treated it as seconds, ie.:

#1.9.3
ruby-1.9.3-p392>> require 'yaml'
=> true
ruby-1.9.3-p392>> YAML.load '1:00'
=> 3600
ruby-1.9.3-p392>> YAML::ENGINE.yamler = 'syck'
=> "syck"
ruby-1.9.3-p392>> YAML.load '1:00'
=> 60

#2.0.0
ruby-2.0.0-p195>> require 'yaml'
=> true
ruby-2.0.0-p195>> YAML.load '1:00'
=> 3600

if this change of behavior is documented somewhere, I'd appreciate if you could point me to it.

thanks!

Start by reproducing the YAML.load examples for psych and syck, focusing on how ":"-delimited integer strings are interpreted. Trace the Psych YAML.load entry point and existing parser tests to determine the intended unit semantics. Done means resolving or documenting the psych-versus-syck behavior and adding coverage for the reported examples.