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New DTW EVAL Built-in Function

Here is the description of the function (this function is not yet in the Net.Data Reference manual).Available on V4R4 and subsequent releases. Ensure you have the latest Net.Data PTF.

DTW_EVAL

Purpose
Evaluate a mathematical expression.

Format
@DTW_EVAL(expression, result)
@DTW_rEVAL(expression)

Parameters
Table 1. DTW_EVAL Parameters

Data Type Parameter Use Description
string expression IN A variable or literal string representing a mathematical expression.
string result OUT A variable that contains the result of evaluating the mathematical expression.

Return Codes
Table 2. DTW_EVAL Return Codes

Return Code Explanation
-1001 The server could not process a Net.Data request to allocate memory.
1001 An input parameter contained a NULL value.
1003 The number of parameters passed on a function call either exceeded the maximum number allowed, or was less than the minimum number required by the function.
1005 A parameter passed on a function call, required to be a string variable,was of a different variable type.
1006 A literal string was passed on a function call for a parameter which was required to be an output parameter.
4003 The mathematical expression is not valid.
4004 An attempt was made to divide a number by zero.

Usage Notes

  1. Valid operators are plus (+), minus (-), multiply (*), divide (/), power (**), and modulus (%). Any other characters, except for numbers and whitespace, are not allowed.
  2. Standard precedence rules will be used. Precedence order can be changed by use of parentheses.
  3. The result of mathematical operations is undefined if integers exceed allowed limits for signed 32-bit integers or floating-point numbers.
  4. The operand that follows a modulus (%) or power (**) operator must be an integer.
  5. The plus (+) and minus (-) operators can be unary operators, as in -3 or +10.
  6. Floats can be expressed in scientific notation.

Examples 

  1. %define calcsum = "($(n) * ($(n) + 1)) / 2"

@DTW_ASSIGN(n, "100")
@DTW_EVAL(calcsum, sum)

  2. %define forumula1 = "(-$(b) + ($(b)**2 - 4*$(a)*$(c))) / (2*$(a))"
%define forumula2 = "(-$(b) - ($(b)**2 - 4*$(a)*$(c))) / (2*$(a))"

...

@DTW_ASSIGN(a, "1")
@DTW_ASSIGN(b, "2")
@DTW_ASSIGN(c, "1")

@DTW_EVAL(formula1, solution1)
@DTW_EVAL(formula2, solution2)