Accessible AST-Based Programming for Visually-Impaired Programmers

Emmanuel Schanzer, Sina Bahram, Shriram Krishnamurthi

ACM Technical Symposium on Computer Science Education, 2019


Most programmers rely on visual tools (block-based editors, auto-indentation, bracket matching, syntax highlighting, etc.), which are inaccessible to visually-impaired programmers. While prior language-specific, downloadable tools have demonstrated benefits for the visually-impaired, we lack language-independent, cloud-based tools, both of which are critically needed.

We present a new toolkit for building fully-accessible, browser-based programming environments for multiple languages. Given a parser that meets certain specifications, this toolkit will generate a block editor familiar to sighted users that also communicates the structure of a program using spoken descriptions, and allows for navigation using standard (accessible) keyboard shortcuts.

This paper presents the toolkit and a first evaluation of it. While the toolkit allows for full editing of code, we chose to focus strictly on navigation for this evaluation, using the navigation-only study design of Baker, Milne and Ladner. Visually-impaired programmers completed several tasks with and without our tool, and we compared their results and experience. Users had improved accuracy when completing tasks, were significantly better able to orient when reading code, and felt better about completing the tasks when using the tool. Moreover, these improvements came with no significant change in task completion time over plain text, even for experienced programmers who navigate text using screen readers set to high words-per-minutes.



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