NAME

       write-tree -  (tree)

PURPOSE

       Insert a key/value pair into a tree.

SYNTAX

           write-tree <tree> key <key> value <value> \
               [ status <status> ] \
               [ new-cursor <cursor> ]

DESCRIPTION

       write-tree inserts string <key> and associated string <value> into <tree> created by new-tree.

       If  <key>  already  exists  in  <tree>, <status> (in "status" clause) will be GG_ERR_EXIST and nothing is
       inserted into <tree>, otherwise it is GG_OKAY.

       If "new-cursor" clause is used, then a <cursor> will be positioned on a newly inserted tree node. You can
       use use-cursor to iterate to nodes with lesser and greater key values.

EXAMPLES

       Insert key "k" with value "d" into "mytree", and obtain status in "st":

           write-tree mytree key k value d status st

       The following is an example of a process-scoped tree. Such a tree keeps its data across the requests, for
       as long as the process is alive.

       In a new directory, create file treesrv.golf and copy to it:

           %% /treesrv public
               do-once
               new-tree t process-scope
               end-do-once

               // Get input parameters
               get-param op
               get-param key
               get-param data

               if-true op equal "add" // Add data to tree
                   write-tree t key (key) value data status st
                   if-true st equal GG_OKAY
                       @Added [<<print-out key>>]
                   else-if
                       @Key exists
                   end-if
               else-if op equal "delete" // Delete data and obtain the value deleted
                   delete-tree t key (key) value val status st
                   if-true st equal GG_ERR_EXIST
                       @Not found [<<print-out key>>]
                   else-if
                       // If found, then delete key and value
                       @Deleted [<<print-out val>>]
                       delete-string val
                   end-if
               else-if op equal "query" // Query tree based on key value
                   read-tree t equal (key) value val status st
                   if-true st equal GG_ERR_EXIST
                       @Not found, queried [<<print-out key>>]
                   else-if
                       @Value [<<print-out val>>]
                   end-if
               end-if
           %%

       Create new application ("pt" for "process tree"):

           sudo mgrg -i -u $(whoami) pt

       Build application:

           gg -q

       Run the tree service:

           mgrg -w 1 pt

       Try it out, add key/value pairs, query, delete, query again:

           # Add key=1 and data=d1
           $ gg -r --req="/treesrv/op=add/key=1/data=d1" --service --exec --silent-header
           Added [1]

           # Add key=2 and data=d2
           $ gg -r --req="/treesrv/op=add/key=2/data=d2" --service --exec --silent-header
           Added [2]

           # Query key=1
           $ gg -r --req="/treesrv/op=query/key=1" --service --exec --silent-header
           Value [d1]

           # Query key=2
           i$ gg -r --req="/treesrv/op=query/key=2" --service --exec --silent-header
           Value [d2]

           # Delete key=2
           $ gg -r --req="/treesrv/op=delete/key=2" --service --exec --silent-header
           Deleted [d2]

           # Query key=2
           $ gg -r --req="/treesrv/op=query/key=2" --service --exec --silent-header
           Not found, queried [2]

       See read-tree for more examples.

SEE ALSO

        Tree

       delete-tree get-tree new-tree purge-tree read-tree use-cursor write-tree See all documentation

$DATE                                               $VERSION                                           GOLF(2gg)