AutoLoad

Arguments

Returns

The _auto_load_alist_, which is a list of all currently stored AutoLoad rules. Each rule is itself formatted as a list. This is the _auto_load_alist_ syntax:

    ((pattern action_func action_arg ...) ...)

The members of each rule list are as follows:

For example, the AutoLoad rules in AutoLoadLib.g (at the time of this writing) would be returned as follows:

    (("P[Tthg]*" DllLoad "libgammaph.so") ("gl[A-Z]*" DllLoad "libgammagl.so")
     ("GLUT_*" DllLoad "libgammagl.so") ("GLU_*" DllLoad "libgammagl.so")
     ("GL_*" DllLoad "libgammagl.so") ("ASCII_*" DllLoad "libgammamgl.so")
     ("KB_*" DllLoad "libgammamgl.so") ("GM_*" DllLoad "libgammamgl.so")
     ("EVT_*" DllLoad "libgammamgl.so") ("[mM][gG][lL]*" DllLoad "libgammamgl.so")
     ("[gG]tk*" DllLoad "gammagtk.so"))

Description

This function gives Gamma a way to look up symbols during run-time. If Gamma comes across an undefined symbol while executing a program, and if the symbol matches the pattern, then Gamma executes the action. Normally the action is either a direct definition of the symbol, or an attempt to load a DLL that defines the symbol, using DllLoad, for example.

The available patterns are as follows:

• * matches any number of characters, including zero.

• [c] matches a single character which is a member of the set contained within the square brackets.

• [^c] matches any single character which is not a member of the set contained within the square brackets.

• ? matches a single character.

• {xx,yy} matches either of the simple strings contained within the braces.

• \c (a backslash followed by a character) - matches that character.

This function is not part of the base Gamma executable. It is provided by a Gamma library AutoLoadLib.g which can be accessed using the Gamma require function like this: require ("/usr/cogent/require/AutoLoadLib.g");

Example

In this example, we use the ClearAutoLoad function to clear the AutoLoad list just to make the steps easier to follow. Once a library is loaded or a symbol is defined, Gamma no longer sends a "Looking for symbol" message. Notice how although NoAutoLoad and ClearAutoLoad remove a pattern from future consideration, any symbols defined or any libraries loaded before they were called remain valid.

    Gamma> require ("/usr/cogent/require/AutoLoadLib.g");
    t
    Gamma> ClearAutoLoad();
    nil
    Gamma> AutoLoad ("[gG]tk*", `DllLoad ("gammagtk.so"));
    (("[gG]tk*" DllLoad "gammagtk.so"))
    Gamma> gtk_arg_new;
    Looking for gtk_arg_new
    (defun gtk_arg_new (arg_type) ...)
    Gamma> gtk_main;
    (defun gtk_main () ...)
    Gamma> testvar;
    Looking for testvar
    Symbol is undefined: testvar
    debug 1> (Ctrl - D)
    Gamma> AutoLoad("testvar", `testvar = 5);
    (("testvar" setq testvar 5) ("[gG]tk*" DllLoad "gammagtk.so"))
    Gamma> testvar;
    Looking for testvar
    5
    Gamma> NoAutoLoad("testvar");
    (("[gG]tk*" DllLoad "gammagtk.so"))
    Gamma> testvar;
    5
    Gamma> ClearAutoLoad();
    nil
    Gamma> gtk_main;
    (defun gtk_main () ...)
    Gamma> gtk_false;
    (defun gtk_false () ...)
    Gamma>  
    	

See Also

ClearAutoLoad, NoAutoLoad, DllLoad