ddlCalc() - single CALC/SET/IF function

ddlCalc() - single CALC/SET/IF function

Prototype:

   void ddlCalc(
      CONTROL *ctl,
      char *OptnStr,
      char *ArgList);

Description:

The ddlCalc() API function encapsulates eleven CALC-related functions.

CALC, SET, IF, WHILE are analogues of the respective ddlCreateCalcObject() statements: CALC, SET, IF, WHILE,

In addition, number valued functions that can be used by CALC are described in the CALC document. String valued functions that can be used by SET are described in the SET document.

UNCALC, UNSET, VLIST, SUB, SUBSTITUTE, INC are extrapolations of the respective Thunderbolt RAD DCL commands: UNCALC, UNSET, VLIST, SUB or SUBSTITUTE, INC.

VALUEOF is a newly minted function that performs variable substitution in strings.

Summary of ddlCalc() sub-functions:

Function	Form of OptnStr	Form of ArgList
CALC	NA	%Var = <expression> CALC %Var = <expression>
SET	NA	SET %Var = <expression>
IF	NA	IF <expression>
WHILE	NA	WHILE <expression>
INC	NA	INC %Var
SUB or SUBSTITUTE	/A - all occurrences /U - ignore case	SUB %Var /v1Old/v1New/ /v2Old/v2New/ ...
UNCALC	/Z - also UNCALC super-globals	UNCALC [<var-list>]
UNSET	/Z - also UNSET super-globals	UNSET [<var-list>]
VALUEOF	NA	VALUEOF <command>
VLIST	NA	VLIST

In this context, the CALC/SET/IF <expression> may contain global variables (variables that begin with '%'), super global variables (variables that begin with '%%'), numeric constants and string constants. It may not contain local variables (variables that do not begin with '%') or field names.

<expression> may also contain special system variables. One class of system variables correspond to the values that were returned by the previous API function. For all API functions except ddlCalc(), when a function terminates, the relevant CONTROL structure members are captured to the API context. The ddlCalc() API function is excepted since it is used for capturing and testing these variables.

System Variables:

All system variables are string variables. In the case where a system variable corresponds to a numeric value, the system variable contains the ascii decimal encoded value.

The mapping for the CONTROL structure members is:

%Status	control.Status
%Warning	control.Warning
%Answer	control.Ans1str; or control.Ans1 if control.Ans1str is null
%Answer1	control.Ans1str; or control.Ans1 if control.Ans1str is null
%Answer2	control.Ans2str; or control.Ans2 if control.Ans2str is null
%Answer3	control.Ans3str; or control.Ans3 if control.Ans3str is null
%Answer1num	control.Ans1
%Answer2num	control.Ans2
%Answer3num	control.Ans3
%Answer1str	control.Ans1str
%Answer2str	control.Ans2str
%Answer3str	control.Ans3str
%Answer1L	control.Ans1L
%Answer2L	control.Ans2L
%Answer3L	control.Ans3L
%Answer4L	control.Ans4L
%Answer5L	control.Ans5L
%Answer6L	control.Ans6L

There are additional system variables that do not correspond to CONTROL structure members.

%LastCommand	the previous API command as <ddlXxx> [/<options>] [<command-string>]
%Level	Calc-Object only; hierarchical level of the current frame
%Null	always SQL null
%Timing	elapsed time for previous function; hh:mm:ss.tt
%USN	user ID for current data base