Programming Guide - Actian

How Procedure Handles Work (ProcHandle Objects)Restrictions to Using the Call MethodThere are some restrictions to using the Call method. This method can beinvoked only in the following places:• In a statement by itself• As the right side of an assignmentThe Call method can never be invoked inside an expression.If a procedure handle represents a local procedure that was defined in a frameor global procedure component, there are two additional restrictions on whenthe Call method can be invoked on the procedure handle:• The Call method cannot be invoked after the frame or global procedure inwhich it was defined (and which contains the scope on which theGetProcHandle was issued) has terminated.• The Call method cannot be invoked from a “thread” other than the one inwhich the GetProcHandle was issued.For example, a frame can create a procedure handle on one of its localprocedures and pass it as a callback routine to a called frame, but not toan opened frame (because the openframe statement creates a newthread).These restrictions do not apply to a procedure handle that represents a globalprocedure or a local procedure defined in a user class script.Global Procedures Available in the Core LibraryThe following global procedures are available in the core library:_StringParseKeywordReturns the values of the specified keyword_StringSubSubstitutes values for %parameters in a string_StringTokenSubSubstitutes a value for a single token in a string. Only the first occurrenceof the token is replaced.The following sections describe these procedures.Writing Scripts and Procedures 89