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Version: 3.1.X

Element <function>

The <function> element starts a declaration block for a reusable function in IsisScript. Functions are essential for modularizing complex scripts and avoiding code repetition.

A unique feature of IsisScript functions is their ability to automatically process parameters passed by the <call> element. The attributes action, tag, split, and from are used to receive and map these parameters into fields, following the same semantics defined for the <field> element.

Usage​

  • Parent element: <IsisScript> (Functions must be declared at the script's root level or within a <section>).
  • Allowed content: <call>, <cgitable>, <define>, <display>, <do>, <export>, <extract>, <field>, <file>, <flow>, <hl>, <label>, <list>, <parm>, <proc>, <return>, <trace>

Syntax​

<function name="FUNCTION_NAME" [action="..."] [tag="..."] [split="..."] [from="..."]>
</function>

Attributes​

AttributeMandatoryDescription
nameYesIdentifies the declared function.
actionNoDefines the operation to perform with the received parameter (e.g., replace, add).
tagNoSpecifies the numeric tag where the parameter will be stored.
splitNoControls how parameter values are split into occurrences.
fromNoDefines the source field number used to pass parameters.

Attribute Details​

name​

The name attribute identifies the declared function. This name is used by the <call> element to invoke the function explicitly.

Example:

<function name="Test" action="replace" tag="1">
  <display>Inside Test function</display>
</function>

action​

*See also: <field action=...>*

The action attribute defines how parameters passed to the function are handled. This attribute is functionally equivalent to the action attribute of the <field> element.

  • Common values: replace (overwrites the tag), add (adds a new occurrence).

Example:

<function name="Test" action="replace" tag="1">
  <display><pft>'Field 1 = ', v1</pft></display>
</function>

tag​

*See also: <field tag=...>*

The tag attribute specifies the field number (tag) used to receive the parameter passed to the function. This attribute is functionally equivalent to the tag attribute of the <field> element.

Example:

<function name="Test" action="replace" tag="1">
  <display>Parameter received: <pft>v1</pft></display>
</function>

split​

*See also: <field split=...>*

The split attribute controls how parameter values passed to the function are stored, specifically if they should be split into multiple occurrences. This attribute is functionally equivalent to the split attribute of the <field> element.

  • Common value: occ (splits the input string by lines into new occurrences).

Example:

<function name="Test" action="replace" tag="1" split="occ">
  <display>Processing multiple lines...</display>
  <display><pft>(v1/)</pft></display>
</function>

from​

*See also: <field from=...>*

The from attribute defines the source field number used to pass parameters to the function. This acts as a filter or specific selector equivalent to the from attribute of the <field> element.

Example:

<function name="Test" action="replace" tag="1" from="200">
</function>

Complete Example​

The following script demonstrates a function ParamTest that receives a parameter, splits it into occurrences, displays it, and then returns a value to the caller.

<IsisScript>

   <function name="ParamTest" action="replace" tag="1" split="occ">
      <display>
         Inside ParamTest function.<br>
         Received argument in v1:<br>
         <pft>(v1/)</pft>
      </display>
      
      <return action="replace" tag="9999" split="occ">
         <pft>'Processed: ', v1</pft>
      </return>
   </function>

   <section>
      <display>Calling Function...<br></display>
      
      <call name="ParamTest">
         <pft>'Line One'/'Line Two'</pft>
      </call>
      
      <display>
         <br>Back in Main Section.<br>
         Returned value in v9999: <pft>v9999</pft>
      </display>
   </section>

</IsisScript>