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3.9.4 Package Sourcing and Autoloading

As mentioned above, packages are usually saved in files and then read into a CoCoA session using the command Source .

(I) Full path name, ordinary file sourcing.

package name: $mypackage
   file name: this/is/my/stuff.cpkg

Suppose the name of your package is $mypackage and is kept in the file with full pathname this/is/my/stuff.cpkg. Then the package can be loaded into the session as usual with the command:

Source "this/is/my/stuff.cpkg";

Functions can then be called from the package using the package name, $mypackage, as a prefix (or using aliases).

(II) The standard package path, $-shortcut.

package name: $mypackage
   file name: packages/mypackages/stuff.cpkg (relative to cocoa directory)

A package is in the standard package path if its file is kept in the packages directory inside the cocoa directory. Suppose your package has name $mypackage and is kept in the file with pathname (relative to the cocoa directory) packages/mypackages/stuff.pkg. Then the package can be read by passing this pathname to Source , as above, but there are the following shortcuts:

  Source "$mypackages/stuff";

In other words, the prefix $ is taking the place of packages/ and the suffix .cpkg is (and must be) left off. Functions can then be called as in the previous case.

(III) Autoloading.

package name: $mypackages/stuff
   file name: packages/mypackages/stuff.cpkg (relative to cocoa directory)

Now suppose that the package is in the standard package path, as above, in the file with pathname (relative to the cocoa directory) packages/mypackages/stuff.cpkg. However, now assume that the name of the package is $mypackages/stuff, i.e., that it matches the name of its file (without packages/ and .cpkg). Then, if any function from the package is called, say $mypackages/stuff.MyFunction, the package will automatically be loaded. Of course, one may also source the package using either method I or II, from above.

* Initialize * NOTE: As explained in the section entitled Package Initialization, below, no matter which method is used to source a package, any function in the package named Initialize will automatically be executed when the package is loaded.