Info Catalog elisp: Customization elisp: Top elisp: Byte Compilation

elisp: Loading

 
 15 Loading
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 Loading a file of Lisp code means bringing its contents into the Lisp
 environment in the form of Lisp objects.  Emacs finds and opens the
 file, reads the text, evaluates each form, and then closes the file.
 Such a file is also called a “Lisp library”.
 
    The load functions evaluate all the expressions in a file just as the
 ‘eval-buffer’ function evaluates all the expressions in a buffer.  The
 difference is that the load functions read and evaluate the text in the
 file as found on disk, not the text in an Emacs buffer.
 
    The loaded file must contain Lisp expressions, either as source code
 or as byte-compiled code.  Each form in the file is called a “top-level
 form”.  There is no special format for the forms in a loadable file; any
 form in a file may equally well be typed directly into a buffer and
 evaluated there.  (Indeed, most code is tested this way.)  Most often,
 the forms are function definitions and variable definitions.
 
    Emacs can also load compiled dynamic modules: shared libraries that
 provide additional functionality for use in Emacs Lisp programs, just
 like a package written in Emacs Lisp would.  When a dynamic module is
 loaded, Emacs calls a specially-named initialization function which the
 module needs to implement, and which exposes the additional functions
 and variables to Emacs Lisp programs.
 
    For on-demand loading of external libraries which are known in
 advance to be required by certain Emacs primitives, Dynamic
 Libraries.
 

Menu

 
· How Programs Do Loading The ‘load’ function and others.
· Load Suffixes           Details about the suffixes that ‘load’ tries.
· Library Search          Finding a library to load.
· Loading Non-ASCII       Non-ASCII characters in Emacs Lisp files.
· Autoload                Setting up a function to autoload.
· Repeated Loading        Precautions about loading a file twice.
· Named Features          Loading a library if it isn’t already loaded.
· Where Defined           Finding which file defined a certain symbol.
· Unloading               How to unload a library that was loaded.
· Hooks for Loading       Providing code to be run when
                               particular libraries are loaded.
· Dynamic Modules         Modules provide additional Lisp primitives.
 

Info Catalog elisp: Customization elisp: Top elisp: Byte Compilation