write-list - (linked-list)

Description

write-list adds a pair of key/value strings to the linked <list>, specified with <key> and <value> (in "key" and "value" clauses, collectively called an "element"). The key/value pair is added just prior to the list's current position, thus becoming a current element. If "append" clause is used without boolean variable <append>, or if <append> evaluates to true, then the element is added at the end of the list, and the list's current element becomes the newly added one.

Examples

Add a key/value pair to the end of the list: new-list mylist write-list mylist key "mykey" value "myvalue" append The following is a list that is process-scoped, i.e. it is a linked-list server, which can add, delete, read and position to various elements: %% /llsrv public // Create linked list just once for the life of the process do-once new-list 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 list // Make a copy of key,data so they are Golf-allocated write-list t key (key) value data append @Added [<<print-out key>>] value [<<print-out data>>] else-if op equal "delete" // Delete first data and obtain the value deleted position-list t first read-list t key (key) value val status st if-true st equal GG_ERR_EXIST @Not found else-if // If found, then delete key and value @Deleted key [<<print-out key>>], [<<print-out val>>] delete-list t end-if else-if op equal "next" // Position to next element position-list t next status st if-true st equal GG_OKAY @Okay else-if @Not found end-if else-if op equal "last" // Position to last element position-list t last status st if-true st equal GG_OKAY @Okay else-if @Not found end-if else-if op equal "previous" // Position to element position-list t previous status st if-true st equal GG_OKAY @Okay else-if @Not found end-if else-if op equal "first" // Get first element position-list t first status st if-true st equal GG_OKAY @Okay else-if @Not found end-if else-if op equal "query" // Get current element read-list t key (key) value val status st if-true st equal GG_ERR_EXIST @Not found else-if @Key [<<print-out key>>], value [<<print-out val>>] end-if else-if op equal "purge" // remove all, keep the list purge-list t end-if %% Create application: sudo mgrg -i -u $(whoami) linkserver Start the server: mgrg -w 1 linkserver Try it out: gg -r --req="/llsrv/op=add/key=1/data=1" --exec --service gg -r --req="/llsrv/op=add/key=2/data=2" --exec --service gg -r --req="/llsrv/op=query" --exec --service gg -r --req="/llsrv/op=previous" --exec --service gg -r --req="/llsrv/op=query" --exec --service