LassoScript Utility
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Tag Link [Null->Invoke] Category Tags
Type Member Source Available No
Support Preferred Version 7.0
Change Unchanged Data Source Any
Output Type Any Security None
Implementation Internal Sets Lasso 8.5, Lasso 8.0, Lasso 7.0


[Null->Invoke] is a member tag which can be used with any data type. The results of calling [Null->Invoke] differ depending on what type it is called on.

Tag - [Tag->Invoke] works just like calling the tag directly. The parameters to [Tag->Invoke] are passed to the tag. For example: [\Field->(Invoke: 'Field_Name')] is equivalent to [Field: 'Field_Name'] or [\Field->(Run: -Params=(Array: 'Field_Name'))].

Pair - If a pair has a tag as its first element and an array as its second element then calling [Pair->Invoke] on it will execute the tag and pass the second element to the tag as its parameter array. Any other parameters passed to [Tag->Invoke] are passed after the first parameters. For example [(Pair: \Field = (Array: 'First_Name'))->Invoke] will yield the same result as [Field: 'First_Name']. This type of pair is called a "closure" and enables a method of implementing callback tags.

Others - Most other types simply return their value when [Null->Invoke] is called on them. This is true for most built-in Lasso types such as integers, decimal values, strings, etc.

Custom Types - Custom types can override the [Type->Invoke] tag in order to provide custom behavior.


[\Tag Name->(Invoke: Parameters)]

[{Compound Expression}->(Invoke: Parameters)]

[(Pair: \Tag Name = Parameters Array->(Invoke: Additional Parameters)]

[(Pair: Compound Expression = Parameters Array->(Invoke: Additional Parameters)]

[Any Type->Invoke]


Optional Parameters
Parameters All parameters are passed to the base data type.


See the Lasso 8 Language Guide for examples of how to use this tag.