I am using YAML for configuration files, which can be hand edited or
modified by software. I would like the comments to survive across a
load/store. Something along these lines:

Conf file:
# Set to your liking
personal_salary: "too small"

# Default should be OK
others_salary: "too much"

# Change only if you know what you are doing(tm)
boss_salary: "insane"

Code example:
$conf, $com = YAML::load(File.open("/path/to/conf"))
-> $conf = { "personal_salary" => "too small", ... }
   $com = { "personal_salary" => "Set to your liking", ... }
$conf["personal_salary"] = "much better"
File.open("/path/to/conf", "w").puts($conf.to_yaml("comments" => $com))

Gives:
# Set to your liking
personal_salary: "much better"

# Default should be OK
others_salary: "too much"

# Change only if you know what you are doing(tm)
boss_salary: "insane"


Is that a doable/interesting feature? Can it be done with the existing
parser or should the syck C code be modified to?

Guillaume.