unbind_free_runtime_expression_string_variable_.htm
Navigation: Language Reference > 10 - Expressions > Runtime Expression Evaluation >====== UNBIND (free runtime expression string variable) ====== | |
UNBIND( [name] )
UNBIND | Frees variables from use in runtime expression strings. |
Name | A string constant that specifies the identifier used by the dynamic expression evaluator. If omitted, all bound variables are unbound. |
The UNBIND statement frees logical names previously bound by the BIND statement. The more variables that are bound at one time, the slower the EVALUATE procedure works. Therefore, UNBIND should be used to free all variables and user-defined procedures not currently available for use in runtime expression strings.
Example:
PROGRAM MAP AllCapsFunc(STRING),STRING !Clarion procedure END Header FILE,DRIVER('Clarion'),PRE(Hea) !Declare header file layout AcctKey KEY(Hea:AcctNumber) OrderKey KEY(Hea:OrderNumber) Record RECORD AcctNumber LONG OrderNumber LONG ShipToName STRING(20) ShipToAddr STRING(20) ShipToCity STRING(20) ShipToState STRING(20) ShipToZip STRING(20) END END Hea:CityStateZip STRING(60) !Make easy to use combined Hea:ZipPlus4 STRING(20) !fix to not have -0000 Detail FILE,DRIVER('Clarion'),PRE(Dtl),BINDABLE !Bindable RECORD structure OrderKey KEY(Dtl:OrderNumber) Record RECORD OrderNumber LONG Item LONG Quantity SHORT END END CODE ! PUSHBIND() good idea BIND('ShipName',Hea:ShipToName) BIND(Dtl:Record) !Make easy to use combined City State Zip with local variable: BIND('Hea:CityStateZip',Hea:CityStateZip) !Do not use the Zip from Header record for normal things: UNBIND('Hea:ShipToZip') BIND('Hea:ShipToZip',Hea:ZipPlus4) !Use Zip fixed for Zip Plus 4 BIND('Hea:ShipToZipRaw',Hea:ShipToZip) !Allow using Raw zip by this name BIND('SomeFunc',AllCapsFunc) !Each time record is loaded: Hea:CityStateZip = CLIP(Hea:ShipToCity)& CHOOSE(~Hea:ShipToState,'',', '&Hea:ZipToState) &' '& Hea:ShipToZip) Hea:ZipPlus4 = Hea:ShipToZip IF Hea:ZipPlus4[6:10]='-0000' THEN CLEAR(Hea:ZipPlus4[6:10]). !Remove -0000 UNBIND('ShipName') !UNBIND the variable UNBIND('SomeFunc') !UNBIND the Clarion language procedure UNBIND() !UNBIND all bound variables ! POPBIND() better alternative than UNBIND() AllCapsFunc PROCEDURE(PassedString) CODE RETURN(UPPER(PassedString))
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unbind_free_runtime_expression_string_variable_.htm.txt · Last modified: 2023/09/08 09:52 by carlbarnes