Info Catalog elisp: Case Changes elisp: Text elisp: Substitution

elisp: Text Properties

 
 31.19 Text Properties
 =====================
 
 Each character position in a buffer or a string can have a “text
 property list”, much like the property list of a symbol (Property
 Lists).  The properties belong to a particular character at a
 particular place, such as, the letter ‘T’ at the beginning of this
 sentence or the first ‘o’ in ‘foo’—if the same character occurs in two
 different places, the two occurrences in general have different
 properties.
 
    Each property has a name and a value.  Both of these can be any Lisp
 object, but the name is normally a symbol.  Typically each property name
 symbol is used for a particular purpose; for instance, the text property
 ‘face’ specifies the faces for displaying the character (Special
 Properties).  The usual way to access the property list is to specify
 a name and ask what value corresponds to it.
 
    If a character has a ‘category’ property, we call it the “property
 category” of the character.  It should be a symbol.  The properties of
 the symbol serve as defaults for the properties of the character.
 
    Copying text between strings and buffers preserves the properties
 along with the characters; this includes such diverse functions as
 ‘substring’, ‘insert’, and ‘buffer-substring’.
 

Menu

 
· Examining Properties   Looking at the properties of one character.
· Changing Properties    Setting the properties of a range of text.
· Property Search        Searching for where a property changes value.
· Special Properties     Particular properties with special meanings.
· Format Properties      Properties for representing formatting of text.
· Sticky Properties      How inserted text gets properties from
                              neighboring text.
· Lazy Properties        Computing text properties in a lazy fashion
                              only when text is examined.
· Clickable Text         Using text properties to make regions of text
                              do something when you click on them.
· Fields                 The ‘field’ property defines
                              fields within the buffer.
· Not Intervals          Why text properties do not use
                              Lisp-visible text intervals.
 

Info Catalog elisp: Case Changes elisp: Text elisp: Substitution