*** empty log message ***

libraries/iTasks/InternaliTasksCommon.dcl

+definition module InternaliTasksCommon
+
+// *********************************************************************************************************************************
+// internally used types and utility function
+// *********************************************************************************************************************************
+// iTask & iData Concept and Implementation: (c) 2006,2007,2008 - Rinus Plasmeijer
+// *********************************************************************************************************************************
+//
+import iDataHandler, iDataFormData
+import iTasksHandler
+
+:: *TSt 		=	{ tasknr 		:: !TaskNr									// for generating unique form-id's
+					, activated		:: !Bool   									// if true activate task, if set as result task completed	
+					, userId		:: !Int										// id of user to which task is assigned
+					, workflowLink	:: !WorkflowLink							// process table entry information
+					, staticInfo	:: !StaticInfo								// info which does not change during a run
+					, html			:: !HtmlTree								// accumulator for html code
+					, options		:: !Options									// iData lifespan and storage format
+					, trace			:: !Maybe [Trace]							// for displaying task trace
+					, hst			:: !HSt										// iData state
+					}
+:: TaskNr			:== [Int]													// task nr i.j is adminstrated as [j,i]
+:: WorkflowLink		:== !(Entry,ProcessIds)										// entry in table together with unique id which is used for checking whether the reference is still valid
+:: Entry			:== !Int
+:: ProcessIds		:== !(!UserId,!ProcessNr,!WorkflowLabel)					// user id, process id and name given to a workflow process; is used as unique identifier in process table
+:: UserId			:== !Int													// a user id of an iTask user must be a unique integer value
+:: ProcessNr		:== !Int
+:: WorkflowLabel	:== !String
+:: StaticInfo	=	{ currentUserId	:: UserId									// id of application user 
+					, threadTableLoc:: !Lifespan								// where to store the server thread table, default is Session
+					}
+:: HtmlTree		=	BT HtmlCode													// simple code
+				|	(@@:) infix  0 TaskName HtmlTree							// code with id of user attached to it
+				|	(-@:) infix  0 UserId 	HtmlTree							// skip code with this id if it is the id of the user 
+				|	(+-+) infixl 1 HtmlTree HtmlTree							// code to be placed next to each other				
+				|	(+|+) infixl 1 HtmlTree HtmlTree							// code to be placed below each other				
+				|	DivCode String HtmlTree										// code that should be labeled with a div, used for Ajax and Client technology
+:: Options		=	{ tasklife		:: !Lifespan								// default: Session		
+					, taskstorage	:: !StorageFormat							// default: PlainString
+					, taskmode		:: !Mode									// default: Edit
+					, gc			:: !GarbageCollect							// default: Collect
+					}
+:: Trace		=	Trace !TraceInfo ![Trace]									// traceinfo with possibly subprocess
+:: TraceInfo	:== Maybe !(!Bool,!(!UserId,!TaskNr,!Options,!String,!String))	// Task finished? who did it, task nr, task name (for tracing) value produced
+:: TaskName		:== !(!UserId,!ProcessNr,!WorkflowLabel,!TaskLabel)				// id of user, workflow process name, task name
+
+// Here follow some commonly used internal functions
+
+/* Support for user defined combinators
+mkTask			:: for making a user defined combinator, name will appear intrace 
+*/
+
+incNr :: !TaskNr -> TaskNr
+mkTask 			:: !String !(Task a) 						-> Task a 		| iCreateAndPrint a
+mkParSubTask 	:: !String !Int (Task a) -> (Task a)  | iCreateAndPrint a					// two shifts are needed
+
+showTaskNr 			:: !TaskNr -> String
+printTrace2 		:: !(Maybe ![Trace]) -> BodyTag
+iTaskId 			:: !Int !TaskNr !String -> String
+deleteAllSubTasks 	:: ![TaskNr] TSt -> TSt
+
+cFormId 			:: !Options !String !a -> FormId a
+sessionFormId 		:: !Options !String !a -> FormId a
+pageFormId 			:: !Options !String !a -> FormId a
+storageFormId 		:: !Options !String !a -> FormId a
+
+
+

libraries/iTasks/InternaliTasksCommon.icl

+implementation module InternaliTasksCommon
+
+// *********************************************************************************************************************************
+// iTask & iData Concept and Implementation: (c) 2006,2007,2008 - Rinus Plasmeijer
+// *********************************************************************************************************************************
+//
+import StdList, StdArray, StdFunc
+import iDataHandler, iDataFormData, iDataTrivial
+import iTasksSettings
+import iTasksHandler, InternaliTasksThreadHandling
+
+
+showTaskNr :: !TaskNr -> String
+showTaskNr [] 		= ""
+showTaskNr [i] 		= toString i
+showTaskNr [i:is] 	= showTaskNr is <+++ "." <+++ toString i 
+
+iTaskId :: !Int !TaskNr !String -> String
+iTaskId userid tasknr postfix 
+# postfix	=	{ c \\ c <-: postfix | not (isMember c ['\\\"/:*?<>|"']) }			// throw away characters not allowed in a file name
+| postfix == ""
+	| userid < 0	= "iLog_"  <+++ (showTaskNr tasknr) 
+	| otherwise		= "iTask_" <+++ (showTaskNr tasknr) 
+| userid < 0		= "iLog_"  <+++ (showTaskNr tasknr) <+++ "-" <+++ postfix
+| otherwise			= "iTask_" <+++ (showTaskNr tasknr) <+++ "-" <+++ postfix //  MJP:info removed to allow dynamic realloc of users:    <+++ "+"  <+++ userid
+
+deleteAllSubTasks :: ![TaskNr] TSt -> TSt
+deleteAllSubTasks [] tst = tst
+deleteAllSubTasks [tx:txs] tst=:{hst,userId} 
+# hst	= deleteIData  (iTaskId userId (tl tx) "") hst
+= deleteAllSubTasks txs {tst & hst = hst}
+
+
+// ******************************************************************************************************
+// Task creation and printing
+// ******************************************************************************************************
+
+incTaskNr tst 		= {tst & tasknr = incNr tst.tasknr}
+
+incNr :: !TaskNr -> TaskNr
+incNr [] = [0]
+incNr [i:is] = [i+1:is]
+
+// mkTask is an important wrapper function which should be wrapped around any task
+// It takes care of
+//		- deciding whether the task should be called (activated) or not
+//		- adding of trace information
+//		- generating task numbers in a systematic way
+// It is very important that the numbering of the tasks is done systematically
+// Every task should have a unique number
+// Every sequential task should increase the task number
+// If a task j is a subtask of task i, than it will get number i.j in reverse order
+
+mkTask :: !String !(Task a) -> (Task a) | iCreateAndPrint a
+mkTask taskname mytask = mkTaskNoInc taskname mytask o incTaskNr
+
+mkTaskNoInc :: !String !(Task a) -> (Task a) | iCreateAndPrint a			// common second part of task wrappers
+mkTaskNoInc taskname mytask = mkTaskNoInc`
+where
+	mkTaskNoInc` tst=:{activated,tasknr,userId,options}		
+	| not activated							= (createDefault,tst)	// not active, don't call task, return default value
+	# (val,tst=:{activated,trace})			= mytask tst			// active, so perform task and get its result
+	# tst	= {tst & tasknr = tasknr, options = options, userId = userId}
+	| isNothing trace || taskname == ""		= (val,tst)				// no trace, just return value
+	= (val,{tst & trace = Just (InsertTrace activated tasknr userId options taskname (printToString val%(0,30)) (fromJust trace))}) // adjust trace, don't print to long values
+
+mkParSubTask :: !String !Int (Task a) -> (Task a)  | iCreateAndPrint a					// two shifts are needed
+mkParSubTask name i task = mkParSubTask`
+where
+	mkParSubTask` tst=:{tasknr, options}
+	# (v,tst) = mkTaskNoInc (name <+++ "." <+++ i) mysubtask {tst & tasknr = [i:tasknr],activated = True} // shift task
+	= (v,{tst & tasknr = tasknr, options = options})
+	where
+		mysubtask tst=:{tasknr} = task {tst & tasknr = [-1:tasknr], activated = True}	// shift once again!
+
+
+// ******************************************************************************************************
+// Trace Printing...
+// ******************************************************************************************************
+
+
+
+InsertTrace :: !Bool !TaskNr !Int !Options String !String ![Trace] -> [Trace]
+InsertTrace finished idx who options taskname val trace = InsertTrace` ridx who val trace
+where
+	InsertTrace` :: !TaskNr !Int !String ![Trace] -> [Trace]
+	InsertTrace` [i] 	who str traces
+	| i < 0					= abort ("negative task numbers:" <+++ showTaskNr idx <+++ "," <+++ who <+++ "," <+++ taskname)
+	# (Trace _ itraces)		= select i traces
+	= updateAt` i (Trace (Just (finished,(who,show,options,taskname,str))) itraces)  traces
+	InsertTrace` [i:is] who str traces
+	| i < 0					= abort ("negative task numbers:" <+++ showTaskNr idx <+++ "," <+++ who <+++ "," <+++ taskname)
+	# (Trace ni itraces)	= select i traces
+	# nistraces				= InsertTrace` is who str itraces
+	= updateAt` i (Trace ni nistraces) traces
+
+	select :: !Int ![Trace] -> Trace
+	select i list
+	| i < length list = list!!i 
+	=  Trace Nothing []
+
+	show 	= idx //showTaskNr idx
+	ridx	= reverse idx
+
+	updateAt`:: !Int !Trace ![Trace] -> [Trace]
+	updateAt` n x list
+	| n < 0		= abort "negative numbers not allowed"
+	= updateAt` n x list
+	where
+		updateAt`:: !Int !Trace ![Trace] -> [Trace]
+		updateAt` 0 x []		= [x]
+		updateAt` 0 x [y:ys]	= [x:ys]
+		updateAt` n x []		= [Trace Nothing []	: updateAt` (n-1) x []]
+		updateAt` n x [y:ys]	= [y      			: updateAt` (n-1) x ys]
+
+printTrace2 		:: !(Maybe ![Trace]) -> BodyTag
+printTrace2 Nothing 	= EmptyBody
+printTrace2 (Just a)  	= BodyTag [showLabel "Task Tree Forest:", Br, STable emptyBackground (print False a),Hr []]
+where
+	print _ []		= []
+	print b trace	= [pr b x ++ [STable emptyBackground (print (isDone x||b) xs)]\\ (Trace x xs) <- trace] 
+
+	pr _ Nothing 			= []
+	pr dprev (Just (dtask,(w,i,op,tn,s)))	
+	| dprev && (not dtask)					= pr False Nothing	// subtask not important anymore (assume no milestone tasks)
+	| not dtask	&& tn%(0,4) == "Ajax "		= showTask cellattr1b White Navy Aqua  Silver  (w,i,op,tn,s)
+	| not dtask	&& tn%(0,6) == "Server "	= showTask cellattr1b White Navy Aqua  Silver  (w,i,op,tn,s)
+	| not dtask	&& tn%(0,6) == "Client "	= showTask cellattr1b White Navy Aqua  Silver  (w,i,op,tn,s)
+	| not dtask								= showTask cellattr1b White Navy Maroon Silver (w,i,op,tn,s)
+	= showTask cellattr1a White Yellow Red White (w,i,op,tn,s)
+	
+	showTask2 attr1 c1 c2 c3 c4 (w,i,op,tn,s)
+	= [Table doneBackground 	[ Tr [] [Td attr1 [font c1 (toString (last (reverse i)))],	Td cellattr2 [font c2 tn]]
+								, Tr [] [Td attr1 [font c3 (toString w)], 					Td cellattr2 [font c4 s]]
+								]
+	  ,Br]
+
+	showTask att c1 c2 c3 c4 (w,i,op,tn,s)
+	= [STable doneBackground 	
+		[ [font c1 (toString w),font c2 ("T" <+++ showTaskNr i)]
+		, [showStorage op.tasklife, font c3 tn]
+		, [EmptyBody, font c4 s]
+		]
+		]
+	isDone Nothing = False
+	isDone (Just (b,(w,i,op,tn,s))) = b
+
+	showStorage Temp		= font Silver "Tmp"
+	showStorage Client		= font Aqua "Cli"
+	showStorage Page		= font Navy "Pag"
+	showStorage Session		= font Navy "Ssn"
+	showStorage TxtFileRO	= font Red   "TxF0"
+	showStorage TxtFile		= font Red   "TxF"
+	showStorage DataFile	= font Red   "DaF"
+	showStorage Database	= font Red   "DaB"
+
+	doneBackground = 	[ Tbl_CellPadding (Pixels 1), Tbl_CellSpacing (Pixels 0), cellwidth
+						, Tbl_Rules Rul_None, Tbl_Frame Frm_Border 
+						]
+	doneBackground2 = 	[ Tbl_CellPadding (Pixels 0), Tbl_CellSpacing (Pixels 0), cellwidth
+						]
+	emptyBackground = 	[Tbl_CellPadding (Pixels 0), Tbl_CellSpacing (Pixels 0)]
+	cellattr1a		=	[Td_Bgcolor (`Colorname Green),  Td_Width (Pixels 10), Td_VAlign Alo_Absmiddle]
+	cellattr1b		=	[Td_Bgcolor (`Colorname Silver), Td_Width (Pixels 10), Td_VAlign Alo_Absmiddle]
+	cellattr2		=	[Td_VAlign Alo_Top]
+	cellwidth		= 	Tbl_Width (Pixels 130)
+
+	font color message
+	= Font [Fnt_Color (`Colorname color), Fnt_Size -1] [B [] message]
+
+// ******************************************************************************************************
+// iTask Storage Utilities
+// ******************************************************************************************************
+
+cFormId :: !Options !String !a -> FormId a
+cFormId  {tasklife,taskstorage,taskmode} s d = {sFormId  s d & lifespan = tasklife, storage = taskstorage, mode = taskmode} 
+
+sessionFormId :: !Options !String !a -> FormId a
+sessionFormId options s d = cFormId options s d <@ if (options.tasklife == Client) Client Session
+
+pageFormId :: !Options !String !a -> FormId a
+pageFormId options s d = cFormId options s d <@ if (options.tasklife == Client) Client Page
+
+storageFormId :: !Options !String !a -> FormId a
+storageFormId  options s d = cFormId options s d <@ NoForm
+
+

libraries/iTasks/InternaliTasksThreadHandling.dcl

+definition module InternaliTasksThreadHandling
+
+// *********************************************************************************************************************************
+// internally used function for Ajax and Client thread handling
+// *********************************************************************************************************************************
+// iTask & iData Concept and Implementation: (c) 2006,2007,2008 - Rinus Plasmeijer
+// *********************************************************************************************************************************
+//
+import InternaliTasksCommon
+
+:: ThreadTable	:== [TaskThread]						// thread table is used for Ajax and OnClient options
+:: TaskThread	=	{ thrTaskNr			:: !TaskNr		// task number to recover
+					, thrUserId			:: !UserId		// which user has to perform the task
+					, thrWorkflowLink	:: !WorkflowLink// what was the name of workflow process it was part off
+					, thrOptions		:: !Options		// options of the task
+					, thrCallback		:: !String		// serialized callback function for the server
+					, thrCallbackClient	:: !String		// serialized callback function for the client (optional, empty if not applicable)
+					, thrKind			:: !ThreadKind 	// kind of thread
+					, thrVersionNr		:: !Int			// version number of application when thread was created
+					}
+:: ThreadKind	=	ServerThread						// Thread which can only be executed on Server
+				|	ClientServerThread					// Thread preferably to be executed on Client, but also runs on Server
+				|	ClientThread						// Thread which can only be executed on the Client 
+				|	ExceptionHandler					// Exception handler only works on server
+				|	AnyThread							// Used for garbage collection
+:: GlobalInfo	=	{ versionNr			:: !Int			// latest querie number of a user
+					, newThread			:: !Bool		// is a new thread assigned to this user (used for Ajax)?
+					, deletedThreads	:: ![TaskNr]	// are there threads deleted (used for Ajax)?
+					}
+
+instance == ThreadKind
+
+showThreadNr :: !TaskNr -> String
+showThreadTable :: *TSt -> (HtmlCode,*TSt)	// watch it: the actual threadnumber stored is one level deaper, so [-1:nr] instead of nr !!
+
+setPUser :: !Int !(GlobalInfo -> GlobalInfo) !*HSt -> (!GlobalInfo,!*HSt) 
+setPUserNr :: !Int !(Int -> Int) !*HSt -> (!GlobalInfo,!*HSt) 
+clearIncPUser :: !Int !(Int -> Int) !*HSt -> (!GlobalInfo,!*HSt) 
+
+administrateNewThread :: UserId *TSt -> *TSt
+mkTaskThread 				:: !SubPage !(Task a) -> Task a 	| iData a										
+mkTaskThread2 				:: !ThreadKind !(Task a) -> Task a 										// execute a thread
+evalTaskThread 				:: !TaskThread -> Task a 												// execute the thread !!!!
+ThreadTableStorage 			:: !(ThreadTable -> ThreadTable) -> (Task ThreadTable)					// used to store Tasknr of callbackfunctions / threads
+ServerThreadTableStorage	:: !(ThreadTable -> ThreadTable) -> (Task ThreadTable)					// used to store Tasknr of callbackfunctions / threads
+ClientThreadTableStorage	:: !(ThreadTable -> ThreadTable) -> (Task ThreadTable)					// used to store Tasknr of callbackfunctions / threads
+ThreadTableStorageGen 		:: !String !Lifespan !(ThreadTable -> ThreadTable) -> (Task ThreadTable)// used to store Tasknr of callbackfunctions / threads
+copyThreadTableToClient 	::  !*TSt -> !*TSt														// copies all threads for this user from server to client thread table
+splitServerThreadsByUser 	:: !*TSt -> !(!(!ThreadTable,!ThreadTable),!*TSt)						// get all threads from a given user from the server thread table
+copyThreadTableFromClient 	:: !GlobalInfo !*TSt -> !*TSt											// copies all threads for this user from client to server thread table
+findThreadInTable 			:: !ThreadKind !TaskNr *TSt -> *(Maybe (!Int,!TaskThread),*TSt)			// find thread that belongs to given tasknr
+insertNewThread 			:: !TaskThread *TSt -> *TSt												// insert new thread in table
+deleteThreads 				:: !TaskNr !*TSt -> *TSt
+findParentThread 			::  !TaskNr !*TSt -> *([TaskThread],*TSt)								// finds parent thread closest to given set of task numbers
+
+serializeThread 			:: !.(Task .a) -> .String
+deserializeThread 			:: .String -> .(Task .a)
+serializeThreadClient 		:: !(Task a) -> String
+deserializeThreadClient 	:: .String -> .(Task .a)
+
+
+deleteSubTasksAndThreads 	:: !TaskNr TSt -> TSt
+deleteAllSubTasksAndThreads :: ![TaskNr] TSt -> TSt
+

libraries/iTasks/StdiTasks.dcl

 definition module StdiTasks
 
+// *********************************************************************************************************************************
 // Main iTask pass thru module exporting all End User iTask modules 
-
-// (c) iTask & iData Concept and Implementation by Rinus Plasmeijer, 2006-2008 - MJP
+// *********************************************************************************************************************************
+// iTask & iData Concept and Implementation: (c) 2006,2007,2008 - Rinus Plasmeijer
+// *********************************************************************************************************************************
+//
 
 import
 
 // iTask End User modules:
 
-			iTasks				// iTask main module and core engine
-		,	iTasks2				// commonly used iTask combinators
-		,	iTasksDB			// iTask simple DB access
-		,	iTasksSettings		// font settings
+			iTasksHandler				// iTask main module and core engine
+		,	iTasksProcessHandling		// creation of iTask Workflow Processes
+
+		,	iTasksEditors				// basic html editors for any type
+		,	iTasksHtmlSupport			// html prompting
+		
+		,	iTasksBasicCombinators		// basic iTask combinators
+		,	iTasksCombinators			// handy set of additional iTask combinators
+		,	iTasksTimeAndDateHandling	// iTasks triggered by time and date 
+		,	iTasksExceptionHandling		// for handling exceptional situations
+		,	iTasksLiftingCombinators	// lifting other domains (e.g. iData) to the iTask domain
+
+		,	iTasksDB					// iTask simple DB access
+		,	iTasksSettings				// font settings
 

libraries/iTasks/iTasksBasicCombinators.dcl

+definition module iTasksBasicCombinators
+
+// *********************************************************************************************************************************
+// This module contains the basic iTasks combinators
+// *********************************************************************************************************************************
+// iTask & iData Concept and Implementation: (c) 2006,2007,2008 - Rinus Plasmeijer
+// *********************************************************************************************************************************
+//
+import iTasksHandler
+
+:: TCl a 			= 	TCl !.(Task a)									// task closure, container for a task used for higher order tasks (task which deliver a task)			
+:: ChoiceUpdate		:== !Bool [Bool] -> [Bool]							// changed checkbox + current settings -> new settings
+
+derive gForm 	TCl						
+derive gUpd 	TCl
+derive gPrint 	TCl
+derive gParse 	TCl
+derive read 	TCl
+derive write 	TCl
+
+
+/*
+Standard monadic combinators on iTasks:
+(=>>)			:: for sequencing: bind
+return_V		:: lift a value to the iTask domain and return it
+*/
+(=>>) infixl 1 	:: !(Task a) !(a -> Task b) 				-> Task b		| iCreateAndPrint b
+return_V 		:: !a 										-> Task a 		| iCreateAndPrint a
+
+/*
+Assign tasks to user with indicated id:
+assignTaskTo 	:: assign task to indicated user, True for verbose reporting
+*/
+assignTaskTo 	:: !Bool !UserId !(LabeledTask a) 			-> Task a		| iData a	
+
+/*
+Repetition and loops:
+foreverTask		:: infinitely repeating Task
+(<!)			:: repeat task (as a loop)   as long as predicate does not hold; also works for tasks that don't require any user interactions (e.g. database access)
+*/
+foreverTask		:: !(Task a) 								-> Task a 		| iData a
+(<!)  infixl 6 	:: !(Task a)  !(a -> .Bool) 				-> Task a 		| iCreateAndPrint a
+
+/*
+Sequencing Tasks:
+seqTasks		:: do all iTasks one after another, task completed when all done
+*/
+seqTasks		:: ![LabeledTask a] 						-> Task [a]		| iCreateAndPrint a
+
+/*
+Choose the tasks you want to do one forehand:
+chooseTask_btn	:: choose ONE task by pressing a button, True for horizontal buttons, else vertical
+chooseTask_pdm	:: as chooseTask_btn, depending on pulldownmenu item selected, Int for initial value
+chooseTask_radio:: as chooseTask_btn, depending on radio item selected, Int for initial value, htmlcode for option explanation 
+
+chooseTask_cb	:: choice N tasks out of N, order of chosen task depending on first arg
+				   (initial setting, effect for all when set, explanation) for each option
+*/
+
+chooseTask_btn 	:: !HtmlCode !Bool![LabeledTask a] 			-> Task a	 	| iCreateAndPrint a
+chooseTask_pdm 	:: !HtmlCode !Int ![LabeledTask a] 			-> Task a	 	| iCreateAndPrint a
+chooseTask_radio:: !HtmlCode !Int ![(HtmlCode,LabeledTask a)]
+
+															-> Task a		| iCreateAndPrint a
+chooseTask_cbox	:: !([LabeledTask a] -> Task [a])
+				   !HtmlCode ![((!Bool,!ChoiceUpdate,!HtmlCode),LabeledTask a)] 
+															-> Task [a] 	| iData a
+
+/*
+Do m Tasks parallel / interleaved and FINISH as soon as SOME Task completes:
+orTask2			:: do both iTasks in any order, combined task completed as any subtask is done
+andTask2		:: do both iTasks in any order (interleaved), task completed when both done
+andTasksCond	:: do tasks in any order until pred holds for finished tasks, string used for naming group of task navigation buttons
+*/
+orTask2			:: !(Task a,Task b) 						-> Task (EITHER a b) 	
+																			| iCreateAndPrint a & iCreateAndPrint b
+andTask2		:: !(Task a,Task b) 						-> Task (a,b) 	| iCreateAndPrint a & iCreateAndPrint b
+andTasksCond	:: !String !([a] -> Bool) ![LabeledTask a] -> (Task [a]) 	| iData a 
+
+/* Support for user defined combinators
+newTask			:: same, but optimized: after completion only result will remembered
+Once			:: task will be done only once, the value of the task will be remembered, important for side effecting functions lifted to iData domain
+*/
+newTask 		:: !String !(Task a) 						-> Task a		| iData a 
+Once 			:: !String !(Task a) 						-> Task a 		| iData a
+
+/* Operations on Task state
+taskId			:: give id of user assigned to task
+userId			:: give id of application user
+*/
+//taskId			:: TSt 				-> (Int,TSt)
+//userId 			:: TSt 				-> (Int,TSt)
+
+/* Experimental department:
+
+   May not work when the tasks are garbage collected !!
+
+-!>				:: a task, either finished or interrupted (by completion of the first task) is returned in the closure
+				   if interrupted, the work done so far is returned (!) which can be continued somewhere else
+channel			:: splits a task in respectively a sender task closure and receiver taskclosure; 
+				   when the sender is evaluated, the original task is evaluated as usual;
+				   when the receiver task is evaluated, it will wait upon completeion of the sender and then get's its result;
+				   Important: Notice that a receiver will never finish if you don't activate the corresponding receiver somewhere.
+*/
+
+(-!>) infix 4 	:: (Task stop) (Task a) 					-> Task (Maybe stop,TCl a) 	| iCreateAndPrint stop & iCreateAndPrint a
+channel  		:: String (Task a) 							-> Task (TCl a,TCl a) 		| iCreateAndPrint a
+

libraries/iTasks/iTasksCombinators.dcl

+definition module iTasksCombinators
+
+// *********************************************************************************************************************************
+// This module contains a collection of handy iTasks combinators defined in terms of the basic iTask combinators
+// with Thanks to Erik Zuurbier for suggesting some of the advanced combinators
+// *********************************************************************************************************************************
+// iTask & iData Concept and Implementation: (c) 2006,2007,2008 - Rinus Plasmeijer
+// *********************************************************************************************************************************
+//
+import iTasksBasicCombinators				 
+
+/* standard monadic combinators on iTasks:
+(#>>)			:: for sequencing: bind, but no argument passed
+return_D		:: return the value and show it in iData display format
+return_VF		:: return the value and show the Html code specified
+*/
+(#>>) infixl 1 	:: !(Task a) !(Task b) 						-> Task b			| iCreateAndPrint b
+return_D		:: !a 										-> Task a			| gForm {|*|}, iCreateAndPrint a
+return_VF 		:: !HtmlCode !a 		  					-> Task a			| iCreateAndPrint a
+
+/* Assign tasks to user with indicated id:
+(@:)			:: will prompt who is waiting for task with give name
+(@::)			:: as @:, a default task name is chosen as label
+(@:>)			:: as @:, no prompting
+(@::>)			:: as @::, no prompting
+*/
+(@:)   infix 3 	:: !UserId !(LabeledTask a)					-> Task a		| iData a
+(@::)  infix 3 	:: !UserId !(Task a)		    			-> Task a		| iData a
+(@:>)  infix 3 	:: !UserId !(LabeledTask a)					-> Task a		| iData a
+(@::>) infix 3 	:: !UserId !(Task a)		    			-> Task a		| iData a
+
+/* Handling recursion and loops:
+repeatTask		:: repeat Task until predicate is valid
+(<|)			:: repeat task (recursively) as long as predicate does not hold, and give error message otherwise
+*/
+repeatTask		:: !(a -> Task a) !(a -> Bool) a 			-> Task a		| iData a
+(<|)  infixl 6 	:: !(Task a)  !(a -> (Bool, HtmlCode)) 		-> Task a 		| iData a
+
+/* Choose out the tasks you want to do one forehand, labels are used to make the choice:
+button 			:: return value when button pressed
+buttonTask		:: do the iTask when button pressed
+chooseTask		:: Choose ONE iTask from list, depending on button pressed, button horizontal displayed
+chooseTaskV		:: as chooseTask, buttons vertical displayed
+
+mchoiceTask		:: Checked tasks will be done SEQUENTIALLY
+mchoiceTask2	:: as mchoiceTask, boolean used for initial setting of the checks
+mchoiceTask3	:: as mchoiceTask2, function can be used to (re)set the checkboxes
+
+mchoiceTask		:: Checked tasks can be done in INTERLEAVED
+mchoiceTask2	:: as mchoiceTask, boolean used for initial setting of the checks
+mchoiceTask3	:: as mchoiceTask2, function can be used to (re)set the checkboxes
+
+*/
+button 			:: !String 	!a 								-> Task a 		| iCreateAndPrint a
+buttonTask		:: !String   !(Task a)						-> Task a 		| iCreateAndPrint a
+chooseTask		:: !HtmlCode ![LabeledTask a] 				-> Task a 		| iCreateAndPrint a
+chooseTaskV 	:: !HtmlCode ![LabeledTask a] 				-> Task a 		| iCreateAndPrint a
+
+mchoiceTasks 	:: !HtmlCode ![LabeledTask a] 				-> Task [a] 	| iData a
+mchoiceTasks2 	:: !HtmlCode ![(!Bool,LabeledTask a)] 		-> Task [a] 	| iData a
+mchoiceTasks3 	:: !HtmlCode ![((!Bool,!ChoiceUpdate,!HtmlCode),LabeledTask a)] 
+															-> Task [a] 	| iData a
+
+mchoiceAndTasks :: !HtmlCode ![LabeledTask a] 				-> Task [a]		| iData a
+mchoiceAndTasks2:: !HtmlCode ![(!Bool,LabeledTask a)] 		-> Task [a] 	| iData a
+mchoiceAndTasks3 :: !HtmlCode ![((!Bool,!ChoiceUpdate,!HtmlCode),LabeledTask a)] 
+															-> Task [a] 	| iData a
+/* Do m Tasks parallel / interleaved and FINISH as soon as SOME Task completes:
+(-||-)			:: do both iTasks in any order, combined task completed as soon as any subtask is done
+(-&&-)			:: do both iTasks in any order (interleaved), task completed when both done
+orTasks			:: do all  iTasks in any order (interleaved), task completed as soon as any subtask is done
+andTasks		:: do all  iTasks in any order (interleaved), task completed when all  done
+andTasks_mu		:: assign task to indicated users, task completed when all done
+*/
+(-||-) infixr 3 :: !(Task a) !(Task a) 						-> Task a 		| iData a
+(-&&-) infixr 4 :: !(Task a) !(Task b) 						-> Task (a,b) 	| iData a & iData b
+orTasks 		:: ![LabeledTask a] 						-> (Task a) 	| iData a
+