What is ‘the syntax’ and why does it matter?

Modified on Fri, 30 Aug at 2:32 PM

The word syntax is used to refer to the detailed structure of the Web URI. This is fundamental to the GS1 Digital Link standard and is very carefully designed. Keys and Key qualifiers – that is, things like GTINs and batch/lot numbers, and GLNs and GLN extensions, are separated by / characters and are ordered. They become more specific as your work from left to right.


This matches the way you probably organise files and folders on your own computer. You have folders and sub folders as you work from a higher level down to a lower level in your system. There is a path from the top level down.


Conversely, attributes like expiry dates, measured weights, GLN destinations and so on, have no natural order and these are provided in the query string as key=value pairs.


The standard includes a long chapter that defines this syntax. It’s written in a machine-readable language (called ABNF) so that software can be built – and has been – that tests whether or not the syntax has been used in a given Web URI. 

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