✎ struct_type [Dinamica EGO]

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====== Struct Type ======

A struct is a container that bundles multiple named values, possibly of different types, into a single value. Each item is retrieved from a struct by name using the matching **Extract Struct** functor for its type.

A struct's main use is as the output of [[Calculate Python Expression]] and [[Calculate R Expression]]. An external Python or R script can produce more than one result in a single run, so both functors collect everything the script assigns to ''dinamica.outputs'' into one struct, returned through a single ''result'' output port. Each named value is then unpacked downstream with the extractor matching its type: [[Extract Struct Number]] for a [[Real Value Type|Real Value]], [[Extract Struct String]] for a [[String Type|String]], [[Extract Struct Table]] for a [[Table Type|Table]], [[Extract Struct Tuple]] for a [[Tuple Type|Tuple]], and [[Extract Struct Lookup Table]] for a [[Lookup Table Type|Lookup Table]]. Each takes the struct and the item's name, and fails if the struct has no item under that name with that type.

===== GUI Editor =====

A struct cannot be edited. As with [[Map Type|Map]] and [[Categorical Map Type|Categorical Map]], its carrier functor's own input is non-editable — a struct can only be produced by connecting the output of another functor, never typed in directly.

===== EGO Script =====

Since a struct can't be edited, it also can't be written as a literal in a script. It's always obtained by calling a functor that produces one, and reused by referencing the variable bound to its output:

<code>
result := CalculatePythonExpression code;
total := ExtractStructNumber result "total";
label := ExtractStructString result "label";
</code>

===== Automatic Conversions =====

Structs can't be converted to or from any other type.

See [[type_system|Type System]] for the complete conversion reference across all types.