14.8.2.13 :noweb

The :noweb header argument controls expansion of “noweb” syntax references (see Noweb reference syntax) when the code block is evaluated, tangled, or exported. The :noweb header argument can have one of the five values: no, yes, tangle, or no-export strip-export.

• no The default. “Noweb” syntax references in the body of the code block will not be expanded before the code block is evaluated, tangled or exported.
• yes “Noweb” syntax references in the body of the code block will be expanded before the code block is evaluated, tangled or exported.
• tangle “Noweb” syntax references in the body of the code block will be expanded before the code block is tangled. However, “noweb” syntax references will not be expanded when the code block is evaluated or exported.
• no-export “Noweb” syntax references in the body of the code block will be expanded before the block is evaluated or tangled. However, “noweb” syntax references will not be expanded when the code block is exported.
• strip-export “Noweb” syntax references in the body of the code block will be expanded before the block is evaluated or tangled. However, “noweb” syntax references will be removed when the code block is exported.
• eval “Noweb” syntax references in the body of the code block will only be expanded before the block is evaluated.

Noweb prefix lines

Noweb insertions are now placed behind the line prefix of the <<reference>>. This behavior is illustrated in the following example. Because the <<example>> noweb reference appears behind the SQL comment syntax, each line of the expanded noweb reference will be commented.

This code block:

-- <<example>>

expands to:

-- this is the
-- multi-line body of example

Note that noweb replacement text that does not contain any newlines will not be affected by this change, so it is still possible to use inline noweb references.