#### 6.5.7 Understanding how prefixes modify output formats

You do not have to define a different format for every possible combination of attribute values for which you specify format-name prefixes, unless you want an effect different from what you would get when content rendered using the base format is prefixed by any run-in heading(s) assigned to the prefix(es). Most often you will not have to define any prefixed formats at all; the presence of a candidate attribute effectively includes the assigned run-in heading in the output for an instance of a given element.

If you have not defined formats named for all the candidate attribute-value combinations for elements listed in [ElementAttrPrefixes] (see §6.5.1 Listing elements whose attributes can affect output formats), DITA2Go uses the base format name, and modifies the output by prefixing content with the run-in headings (if any) assigned to the candidate attribute values for that instance of the element (see §6.5.4 Assigning run-in headings to format-name prefixes). If the base format itself includes the runin property (see §7.6.2 Specifying default properties for character formats and §7.6.3 Specifying default properties for paragraph formats), its run-in heading follows the attribute run-in heading(s).

If a base format for the element is neither defined nor listed in [FormatAliases] (see §7.3.2 Mapping legacy names to defined formats), the output for that element will have only the default format properties for block or inline elements.

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Parent Topic: 6.5 Mapping element attributes to output formats

Sibling Topics:

6.5.1 Listing elements whose attributes can affect output formats

6.5.2 Listing attributes whose values can affect output formats

6.5.3 Assigning format-name prefixes to attribute values

6.5.4 Assigning run-in headings to format-name prefixes

6.5.5 Deciding which formats need a run-in heading property

6.5.6 Understanding the order of prefixes for multiple attributes

6.5.8 Understanding default attribute-based prefixes and headings