1. help()
     Display loaded help entried as a tree structure. 
  2. help( keywords :string, run = 0 )
     Display the help entry for keywords.

     The keywords can contain single or multiple dot delimited keywords, which tells the 
     help system how to find the help file for these keywords. For example, with AA.BB.CC
     , the help system will first search a module file named help_AA_BB_CC.dao, if failed
     , it will search help_AA_BB.dao, and then help_AA.dao. If such file is found, it wil
     l be loaded as a normal module, and the content of the help will be extracted via th
     e callbacks for the verbatim strings. On successful loading, the help entries from t
     he module will be added to the tree in the help system.

     Then the help entry with id AA.BB.CC will be searched in the help system, and printe
     d to the standard output if found. If run in non-zero, all the embedded tests will b
     e executed and checked.

     Loading a help file as a normal module will guarantee that it is loaded only once, i
     f it hasn't been modified since the last loading, otherwise, it will be reloaded to 
     update the relevant help entries in the help system.

  3. help( object :any, keywords :string, run = 0 )
     Display the help entry for keywords that is associated with the type of object.

     This method adds a prefix that is built from the type name of object to the keywords
     ,  then hehave identically to help( keywords :string, run = 0 ). The prefix consts o
     f the non template-like part of the type name, with double colons being replaced by 
     single dots. An additional dot is appended to the end of the prefix.