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7.4 Loading pickles as Modules

Suppose we want to write a Poke program to extract the contents of sections in a given ELF object file. Extracting sections requires dealing with several data structures encoded in the ELF file, such as the header, the section header table, the string table (that contains the names of the sections) and so on. It would be of course possible to define Poke types for these structures in the script itself but, as it happens, GNU poke ships with an already written pickle that describes the ELF structures. It is called

So a script needing to mess with ELF data structures can just make use of using the load construction:

load elf;

This looks for a file called in a set of directories, which are predefined by poke, and loads it. The list of directories where poke looks for pickles is stored in the load_path variable as a colon separated list of directory names, and can be customized:

$ poke
(poke) load_path

The default value of load_path contains both user-specific directories and system-wide directories. This assures that all the pickles installed by poke are available, and that the user can load her own pickles in her scripts.

Once a pickle is loaded in a script the types, functions and variables defined in it (either directly or indirectly by loading its own pickles) become available.