Expression Builder - Basic Mode

This working mode uses a natural-like conditional expression format based on logical and comparison operators and Composer variables.

The Basic working mode is available for conditional looping and flow control constructs, such as While, Do...While, and If.

To define a conditional expression using the Basic mode:

  1. Click into the Command String column and then click the button. The Expression Builder GUI appears as shown in Figure:Expression Builder - Basic Mode GUI:
  2. Figure:Expression Builder - Basic Mode GUI

  3. Define an expression as follows:
    1. Click into the Variable column and choose a variable from those defined in the previous test steps. Both simple and composite variables are shown.
    2. From the Relation column choose a comparison operator.
    3. From the Value column specify a value or an expression (possibly containing other Composer variables) to compare against.
    4. If the variable involved in the conditional expression is a list, you can use an aggregator from the Aggregation column to reduce it to a single value.
    5. The supported aggregators are the following:

      • Any: When applied to a list, any list member must meet the condition. For example, a condition such as all: var_list >11 yields true if any list member is greater that `11'.
      • All: When applied to a list, all list members must meet the condition. For example, a condition such as all: var_list >11 yields true if all list members are greater that `11'.
      • Last: Selects the last list member in order to evaluate the expression.
      • Min, Max, Med: Selects the minimum, maximum, or median value of all list elements in order to evaluate the expression. If the list contains an odd number of elements, after list sorting the middle element is selected. If the list contains an even number of elements, after performing a list sorting, the average of the middle two elements is selected.
      • Mean: Computes the mean value of list member values before evaluating the expression.
      • Count: Computes the number of list elements.
      • Sum: Computes the sum of list member values before evaluating the expression.
  4. If you want to create multiple sub-expressions joined by a logical operator – AND (default), OR – click the > Condition button and perform the steps sequence repeatedly.
  5. Eventually click the button to complete the operation.

After having defined an expression using the Basic mode you can convert it to a Tcl-enabled expression by clicking the Advanced radio button. A warning message appears indicating this is an operation that cannot be undone and the expression is converted to an advanced expression that contains Tcl functions and operators.