Hi Marcel,

On Mon, May 18, 2020 at 7:05 AM Marcel Taeumel <marcel.taeumel at hpi.de>
wrote:

> Hi, there!
>
> In the #fields method of a new ExternalStructure, how can I express a
> pointer to another external structure?
>
> First, non-pointer works as expected:
> ^ #( (other MyStruct) )
>
> Second, this just treats it as a void*, which returns a generic
> ExternalData:
> ^ #( (other 'MyStruct*') )
>
> Third, this gives me a debugger:
> ^ #( (other MyStruct *) )
>
> :-)
>

ExternalStructure class>>#compileFields:withAccessors: implies it is some
variation on (filedName 'StructType *). See

fieldName := spec first.
fieldType := spec second.
isPointerField := fieldType last = $*.
fieldType := (fieldType findTokens: '*') first withBlanksTrimmed.
externalType := ExternalType atomicTypeNamed: fieldType.
selfRefering := isPointerField and: [externalType isNil and: [fieldType =
self asString]].
selfRefering ifTrue: [
externalType := ExternalType void asPointerType
] ifFalse:[
externalType == nil ifTrue: ["non-atomic"
Symbol
hasInterned: fieldType
ifTrue: [:sym | externalType := ExternalType structTypeNamed: sym].
].
externalType == nil ifTrue:[
Transcript show: '(' , fieldType , ' is void)'.
externalType := ExternalType void.
].

So ...isPointerField should be true.
ExternalType atomicTypeNamed: 'MyStruct*' should answer nil.
ExternalType structTypeNamed: sym should receive MyStruct.
If MyStruct doesn't answer anything (externalType is nil) then an error
should appear in the transcript.

HTH
_,,,^..^,,,_
best, Eliot
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