This page is for data modellers and application designers who need to reuse segments of scripts or expressions in multiple places.

Overview

Sometimes we might want to write our own expressions that can be used time and again. To do this:

In the PhixFlow repository, add a new Macro item and name it.
Add minimum and maximum parameters.
Copy in the expression you want to reuse.
To make an expression reusable in different contexts, change all references to named items to arguments, such as , $args[1]
To use the macro in an expression, specify: macro_name(argument_name).

Sections on this page

For example, we want to reuse an expression:

if( out.AppleHarvestDate < 1, 1, 0)

Create a macro called isGreaterThanOne that contains the expression:

if($args[1] > 1, 1, 0)

To use the macro, replacing $arg[1] with the pipe and attribute name _out.AppleHarvestDate:

isGreaterThanOne(_out.AppleHarvestDate)

Macro Properties

For information about the properties toolbar, and about the sections Parent Details, Analysis Models, Description and Audit Summary, see Common Properties. For a full list of all the PhixFlow property tabs and windows, see Property Tabs.

Basic Settings

Field	Description
Name	The name of the macro. This name is also how the macro will be invoked (called) from elsewhere in PhixFlow
Minimum Parameters	The minumum number of parameters that must be passed to the macro when it is invoked.
Maximum Parameters	The maximum number of parameters that may be passed to the macro when it is invoked.

Expression

Field	Description
Expression	Enter the expression that evaluates to a value based on the input parameters.

Example

Thie following macro is called padCost. It takes 1 parameter - a numeric value. It checks to see if the numeric value is missing a 0 before a decimal point. If so, it adds the 0 and returns the string. It can be called anywhere in PhixFlow that an expression can be entered. For example, by entering padCost(".977")

do(
  $val = $args[1],
  if( startsWith($val, "."),
    // if the cost is positive, add a zero onto the beginning
    "0" + $val,
    // ELSE
    if( startsWith($val, "-."),
      //if the cost is negative, replace the -. with a -0.
      "-0." + substring($val,3),
      //ELSE
      $val
    )
  )
)

PhixFlow 8.3 Help

Macro

Overview

Macro Properties

Basic Settings

Expression

Example

See also: