internals.texi

@ignore @node Semantic Internals @chapter Semantic Internals @c This 'ignore' section fools texinfo-all-menus-update into creating @c proper menus for this chapter. @end ignore

This chapter explains the internals of @semantic{}. This information would not be needed by neither application developers nor grammar developers.

It would be useful mostly for the hackers who would like to learn more about how @semantic{} works.

@section Semanticdb

@acronym{Semanticdb} complexity is certainly an issue. It is a rather hairy problem to try and solve.

This is just an overview really. The basic organization is this:

@table @file @item semanticdb.el Defines a @dfn{database} and a @dfn{table} base class. You can instantiate these classes, and use them, but they are not persistent.

This file also provides support for @code{semanticdb-minor-mode}, which automatically associates files with tables in databases so that tags are @emph{saved} while a buffer is not in memory.

Lastly, it has that @dfn{root} stuff in it. Basically, it is a system by which a file can be associated with the root of a project, so if you have a tree of directories and source files, it can find the root, and allow a tag-search to span all available databases in that directory hierarchy.

@item semanticdb-file.el Subclass the base class database so that it can be saved to disk. Implements all the hooks needed to unbind/rebind tags to a buffer while writing them to a file. Overrides various methods as necessary.

@item semanticdb-system.el Subclass @code{semanticdb-file}. Supports creating a @acronym{DB} in a directory you do not have write-access to, and saving the cache in your home directory. Also implements a @acronym{C}/@acronym{C++} subclass which can be used for caching @file{/usr/include}. (A rather slow process.)

@item semanticdb-el.el Implements a different kind of @dfn{system} database that uses Emacs internals to perform queries. Sadly, this shows a problem of nomenclature since it is not a @code{semanticdb-system-database} (which saves to a file), but database with no file component that queries system tags in a different way.

@item semanticdb-find.el Infrastructure for searching groups @semantic{} databases, and dealing with the search results format. @end table

New things partly written, or to be written someday.

@table @file @item semanticdb-postgres.el Any @acronym{DB} would do, @acronym{MySQL} would be fine. Basically write tags into a relational database, and provide searching facilities. This is probably the only way to allow fast look-ups in humongous source areas. Another possibility would be something like what @acronym{Cscope} does.

@item semanticdb-java.el A system database for @acronym{Java} that uses @acronym{JDEE} @acronym{BeanShell} queries.

@item semanticdb-obj.el A system database that uses command line tools to rip symbols out of @file{.so}, or @file{.a}, or @file{.o} files, and translates into tags.

@item semanticdb-javascript.el A recent notion that somehow knows all those built-ins @acronym{JavaScript} has. @end table

@c LocalWords: Cscope JDEE BeanShell JavaScript MySQL Semanticdb