<MvREFERENCE>

   Also See:   MvASSIGN MvREFERENCEARRAY  

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Creates a reference from one variable to another, such that changes to one will appear to be made to the other. It can be also used to refer to a variable named created with an expression, like the miva_variable_value() function.
Syntax 
<MvREFERENCE NAME = "string: {  expression } | literal"
             INDEX="numeric: {  expression } | literal" 
             MEMBER="string: {  expression } | literal" 
             VARIABLE = "{ expression } | variable name">
  • Empty Tag

Attributes

  • NAME: Required. Source Variable Name
  • * INDEX: Optional. Index to the variable in NAME
  • * MEMBER: Optional. Member to the variable in NAME
  • VARIABLE: Required. Target Variable Name or an expression that results in a variable name

NOTE: * INDEX and MEMBER refer to the variable in the NAME parameter, NOT the VARIABLE parameter.

Examples

In its simplest form on variable can be directly referenced by another name.

Example:

<MvREFERENCE NAME = "g.global" VARIABLE = "l.local">

In typical usage a sub member of a structure or array can be referenced simplifying programming syntax.

For this example assume an array of data like this.

l.products[1]:id = 27
l.products[1]:code = "polol042"
l.products[1]:name = "Polo Shirt"

A string expression creates a reference to an array record assign to item.

Example:

<MvASSIGN NAME="l.posn" VALUE="{ 1 }">
<MvREFERENCE NAME = "l.prod" VARIABLE = "{ 'l.products[' $ l.posn $ ']' }">

The variable l.prod now contains a reference to the array index such that l.prod:code is the same as l.products[1]:code. Using this in a loop results in clearer code.

Example:

<MvASSIGN NAME = "l.posn" VALUE = 1>
<MvASSIGN NAME = "l.last " VALUE = "{ miva_array_max(l.products)}">


<MvWHILE EXPR = "{ l.posn LE l.last }">
    <MvREFERENCE NAME = "l.prod" VARIABLE = "{ 'l.products[' $ l.posn $ ']' }">

    ID: <MvEVAL EXPR = "{ l.prod:id }"><br>
    Code: <MvEVAL EXPR = "{ l.prod:code }"><br>
    Name : <MvEVAL EXPR = "{ l.prod:name }"><br>

    <MvASSIGN NAME = "l.posn " VALUE = "{ l.posn + 1 }">
</MvWHILE>

 

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