Alph Simple Selectors: Overview

Draft J86

The Alph Project: <>
This document indexed at: <>
©2019 Adam C. Moore (LÆMEUR) <>

In Alph we use some simple numeric fragment selectors for addressing, linking, and transclusion of "flat" media — text, images, audio, and video streams. A great mess of heterogeneous fragment selectors/schemes already exist for a variety of media types – have a look through Section 4 of the Web Annotation Data Model for a taste of them: <> – but rather than try to implement an ugly handful of nominal "standards", we designed the Alph Simple Selectors to be terse, easy to parse, and to provide a baseline addressing capability for common media types.

There are three fragment types: POINT, RANGE, and and AREA; and each fragment type has three selectors: INTEGER, FLOAT, and NORMAL. Here's the whole list, with examples of what they look like:

POINT Selectors

Form: #index

RANGE Selectors

Form: #origin-extent

AREA Selectors

Form: #originX,originY[,originZ][...]-extentX,extentY[,extentZ][...]

These fragment selectors can all be easily identified by a regular expression match. The testing regexp is provided in the detailed descriptions.

The units represented by the numbers vary, according to media type. For example, an intRange fragment of #0-100 would refer to the first one-hundred FRAMES of a video stream or the first one-hundred CODEPOINTS of a plain-text file. The units for each media type are given in the detailed descriptions of each selector.