Invalid Function 'document'

Hi all, our team want to create a validation on the fly to verify the size of a document that is uploaded. However, it's giving this error:

Error evaluating function 'document' : Expression evaluation error : Invalid function document.

Is there any way i can solve this?

Our idea is to create some validations (about the document) before the form is submitted. But, since the document ID doesn't exists before the form is submitted, we cant apply the document fucntion to retrieve some document properties.

Here is the sample code:

=a!formLayout(
label: "Lorem Ipsum",
instructions: "Lorem Ipsum",
firstColumnContents: {
a!fileUploadField(
label: "Upload resume",
instructions: "Any format is acceptable.",
target: ri!targetFolder,
value: ri!file,
saveInto:ri!file,
required: true,
validations:
if(isnull(ri!file), null, if(document(todocument(ri!file), "size") > 1000, "BIG", "SMALL"))


)
},
secondColumnContents: {},
buttons: a...

OriginalPostID-264348