Display logic for EPUB accessibility summary

[jonaslil]

In the EPUB Techniques, 4.8.3 Instructions, the following instruction determines the display of the accessibility summary:

4. ELSE IF accessibility_summary is NOT empty:
   THEN display the content of accessibility_summary with language_accessibility_summary as language.

I see two problems here:

1. Skipped block due to ELSE IF

If the variable lang_attribute_accessibility_summary is not empty (i.e., the condition in step 2 is true), the algorithm skips over the entire block containing the ELSE IF. As a result, even if an accessibility summary is present, it won't be displayed.

Solution:
Change the ELSE IF in step 4 to a standalone IF, so the check for accessibility_summary is always performed regardless of the earlier conditions.

2. Misuse of accessibility_summary

The variable accessibility_summary is a Boolean that indicates whether an accessibility summary is present in the document. It does not contain the actual content of the summary. As written, the instruction attempts to display the Boolean value (true or false), which is not the intended behavior.

Solution:
Define a new variable that holds the text content of the accessibility summary. For example:

LET accessibility_summary_content be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilitySummary"]/text()

Then, step 4 should read:

IF accessibility_summary:
THEN display the content of accessibility_summary_content with language_accessibility_summary as language.

[clapierre]

You are correct, we will update the spec. Nice catch @jonaslil