| GOLF(2gg) | Development | GOLF(2gg) |
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
| $VERSION | $DATE |