6.2 The Source File Recording Facility

6.2.1 About source file definitions

Defining an object is a way to name and describe an object. For example, you can define a named function and specify its behavior by using the Common Lisp macrodefun. The Source File Recording Facility records definitions of functions, macros, and structures. It can be extended to record definitions of objects of other types.

Redefining an object assigns a new definition to a previously defined object. Giving a named object the same definition that you originally specified is also considered a redefinition.

When source file recording is enabled, defining and redefining objects has the following effects:

When you redefine an object, the redefinition warning gives you the name of the source file containing the original definition.
When you load a file, redefinition warnings distinguish among multiple definitions, redefinitions, and reloading a file as follows:
- If an object has been defined in a previous loading of the same file, warnings are suppressed.
- If an object has been defined earlier in the same file, you are warned that the object has multiple definitions.
- If an object has been previously defined in another file, you are warned that the object is being redefined and are given the name of the source file containing the previous definition.

You can use the functionget-source-file to get the pathname of the source file that contains the definition of an object.

The Source File Recording Facility is enabled by default. To stop source file recording, set the variable *record-source-files* to nil. Stopping source file recording does not delete old information; if you want to remove source file information, use the function discard-source-file-info. You might want to remove source file information before you save an image to reduce the image size.

To restart source file recording, set the variable*record-source-files* to a non-nil value.

The Advanced User's Guide - 9 SEP 1996

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