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Understanding MivaScript Functions#

Defining and Using Merchant Functions#

Merchant functions let you package reusable logic into named routines. They follow the same tag syntax but introduce their own attributes.

Declaring a Function#

<MvFUNCTION NAME="MyFunction" PARAMETERS="var.input1, input2" STANDARDOUTPUTLEVEL="">
  ...function body...
</MvFUNCTION>
  • NAME sets the function’s identifier.
  • PARAMETERS lists comma‑separated inputs. Prefix with var to pass by reference. Inside the body, each parameter is available as l.parameterName.
  • STANDARDOUTPUTLEVEL (optional) controls output visibility based on debug settings.

Returning Values#

Inside a function, compute intermediate values with <MvASSIGN>, then use <MvFUNCTIONRETURN> to send back your result:

<MvFUNCTION NAME="AddNumbers" PARAMETERS="a, b">
  <MvASSIGN NAME="l.sum" VALUE="{ l.a + l.b }">
  <MvFUNCTIONRETURN VALUE="{ l.sum }">
</MvFUNCTION>

Invoking Functions#

Once defined, call your function in several ways:

  • Inline output via <MvEVAL>:

<MvEVAL EXPR="{ MyFunction(5, 3) }">
* Conditional checks in <MvIF> or <MvWHILE>:

<MvIF EXPR="{ IsUserVIP(customerId) }">…</MvIF>
* Variable assignment with <MvASSIGN>:

<MvASSIGN NAME="l.result" VALUE="{ ComputeOrderValue(var.cart, 0.08) }">