Hello,

I'm trying to access the primitive type of a data type that wraps it from an array of those Data's.

Made simple: Array of Datas that wrap a single primitive type.

My question is the following:

Why does the following work and the latter doesn't?

    Type columnType = typeof(wrappedColumn[0]).fields[0].type
    Type columnType = typeof(wrappedColumn).fields[0].type.fields[0].type

The second gets the type of the array, which should contain a single field holding the cell type (typeof(wrappedColumn).fields[0].type), and gets the primitive type (.fields[0].type) from the Data as in the previous line. However, this results with an index out of bounds exception.

I am unsure, whether, I'm doing something wrong or something else is taking place.

If you are struggling to recreate the error I could provide the complete code.

Many thanks,

Sava

Hi Sava :-)

I'm not 100% sure I understand your scenario; could you post a more complete example with the data types involved and maybe I can see something?

jess

Hello again, jess,

Apologies for the vague question. Here is the concrete example:

https://github.com/savakazakov/CSVUtilExtension/blob/07da6e213d95cd7384bf67cfc3e96e015c111780/CSVUtilExtension.dn#L40

Originally I had the following line:

  Type columnType = typeof(wrappedColumn[0]).fields[0].type

However, this runs into the problem of having the user supply an empty wrappedColumn, at which point this will throw an index out of bounds exception. Then I realised that one can get the type of the cells in the array like this:

 typeof(wrappedColumn).fields[0].type

And if we combine both, we get:

 Type columnType = typeof(wrappedColumn).fields[0].type.fields[0].type

Unfortunately, this somehow loses the information of the "lowest-level" type, i.e. columnType is empty. I might be missing something very obvious here, but I think these two variants should have the same semantics.

Many thanks,

Sava

Hi Sava :-)

I have tried to adapt your code to an example of the simplest, but hopefully equivalent, form. I think the below code is a faithful representation:

component provides App requires io.Output out, data.IntUtil iu {

	void takeData(Data d[]) {
		Type columnType = typeof(d).fields[0].type.fields[0].type

		if (columnType == null)
			out.println("no type!")
			else
			out.println("type-class: $(columnType.class); size: $(columnType.size)")
	}

	int App:main(AppParam params[]) {
		
		int8 val = 9

		Type cellType = new Type(Type.DATA, 0, 0, new Field(new Type(Type.INTEGER, 0, 8), "Integer"))
		Data d = new Data() from cellType

		Type arrayType = new Type(Type.ARRAY, 0, 0, new Field[](new Field(cellType, "WrappedInteger")))
		Data curArray[] = new Data[1] from arrayType

		Data curCell = new Data() from cellType

		curCell:.0 = val
		curArray[0] = curCell

		takeData(curArray)

		return 0
	}
	
}

...but this seems to print out the expected thing, so I think I still might be missing something here :-(

jess