PROPERTY LIST FUNCTIONS

GET THE VALUE OF A SYMBOL'S PROPERTY

Use SETF with GET to add or change properties.

• <sym> the symbol
• <prop> the property name
• <dflt> value to return if property not found, default is NIL
• returns the property value or <dflt> if property doesn't exist.

Use SETF with GETF to add or change properties. (NOTE--when used with SETF, <place> must be a valid place form. It gets executed twice, contrary to Common Lisp standard.)

• <place> where the property list is stored
• <prop> the property name
• <dflt> value to return if property not found, default is NIL
• returns the property value or <dflt> if property doesn't exist.

Modern practice is to use (SETF (GET...)...) rather than PUTPROP.

• <sym> the symbol
• <val> the property value
• <prop> the property name
• returns the property value

Defined as a macro in COMMON.LSP

• <place> where the property list is stored
• <prop> the property name
• returns T if property existed, else NIL

• <sym> the symbol
• <prop> the property name
• returns NIL