Attribute References Substitutions

Attribute references are replaced with their values when they’re processed by the attributes substitution step.

Default attributes substitution

Table 1 lists the specific blocks and inline elements the attributes substitution step applies to automatically.

Table 1. Blocks and inline elements subject to the attributes substitution
Blocks and elements	Substitution step applied by default
Attribute entry values	Yes
Comments	No
Examples	Yes
Headers	Yes
Literal, listings, and source	No
Macros	Yes (except passthrough macros)
Open	Yes
Paragraphs	Yes
Passthrough blocks	No
Quotes and verses	Yes
Sidebars	Yes
Tables	Varies
Titles	Yes

attributes substitution value

The attributes substitution step can be modified on blocks and inline elements. For blocks, the step’s name, attributes, can be assigned to the subs attribute. For inline elements, the built-in values a or attributes can be applied to inline text to add the attributes substitution step.