view man/lispref/databases.texi @ 5142:f965e31a35f0

reduce lcrecord headers to 2 words, rename printing_unreadable_object -------------------- ChangeLog entries follow: -------------------- man/ChangeLog addition: 2010-03-13 Ben Wing <ben@xemacs.org> * internals/internals.texi (Working with Lisp Objects): * internals/internals.texi (Writing Macros): * internals/internals.texi (lrecords): More rewriting to correspond with changes from *LRECORD* to *LISP_OBJECT*. modules/ChangeLog addition: 2010-03-13 Ben Wing <ben@xemacs.org> * postgresql/postgresql.c (print_pgconn): * postgresql/postgresql.c (print_pgresult): printing_unreadable_object -> printing_unreadable_object_fmt. 2010-03-13 Ben Wing <ben@xemacs.org> * ldap/eldap.c (print_ldap): printing_unreadable_object -> printing_unreadable_object_fmt. src/ChangeLog addition: 2010-03-13 Ben Wing <ben@xemacs.org> * alloc.c (alloc_sized_lrecord_1): * alloc.c (alloc_sized_lrecord_array): * alloc.c (old_alloc_sized_lcrecord): * alloc.c (disksave_object_finalization_1): * alloc.c (mark_lcrecord_list): * alloc.c (alloc_managed_lcrecord): * alloc.c (free_managed_lcrecord): * alloc.c (tick_lcrecord_stats): * alloc.c (sweep_lcrecords_1): * buffer.c (print_buffer): * buffer.c (DEFVAR_BUFFER_LOCAL_1): * casetab.c: * casetab.c (print_case_table): * console.c (print_console): * console.c (DEFVAR_CONSOLE_LOCAL_1): * data.c (print_weak_list): * data.c (print_weak_box): * data.c (print_ephemeron): * data.c (ephemeron_equal): * database.c (print_database): * database.c (finalize_database): * device-msw.c (sync_printer_with_devmode): * device-msw.c (print_devmode): * device-msw.c (finalize_devmode): * device.c: * device.c (print_device): * elhash.c: * elhash.c (print_hash_table): * eval.c (print_subr): * eval.c (print_multiple_value): * event-stream.c (event_stream_resignal_wakeup): * events.c (clear_event_resource): * events.c (zero_event): * events.c (print_event): * extents.c: * extents.c (print_extent): * file-coding.c (print_coding_system): * font-mgr.c: * font-mgr.c (Ffc_init): * frame.c: * frame.c (print_frame): * gc.c: * gc.c (GC_CHECK_NOT_FREE): * glyphs.c: * glyphs.c (print_image_instance): * glyphs.c (print_glyph): * gui.c (print_gui_item): * gui.c (copy_gui_item): * keymap.c (print_keymap): * keymap.c (MARKED_SLOT): * lisp.h: * lisp.h (struct Lisp_String): * lisp.h (DEFUN): * lisp.h (DEFUN_NORETURN): * lrecord.h: * lrecord.h (NORMAL_LISP_OBJECT_UID): * lrecord.h (struct lrecord_header): * lrecord.h (set_lheader_implementation): * lrecord.h (struct old_lcrecord_header): * lrecord.h (struct free_lcrecord_header): * marker.c (print_marker): * mule-charset.c: * mule-charset.c (print_charset): * objects.c (print_color_instance): * objects.c (print_font_instance): * objects.c (finalize_font_instance): * print.c (print_cons): * print.c (printing_unreadable_object_fmt): * print.c (printing_unreadable_lisp_object): * print.c (external_object_printer): * print.c (internal_object_printer): * print.c (debug_p4): * print.c (ext_print_begin): * process.c (print_process): * rangetab.c (print_range_table): * rangetab.c (range_table_equal): * scrollbar.c (free_scrollbar_instance): * specifier.c (print_specifier): * specifier.c (finalize_specifier): * symbols.c (guts_of_unbound_marker): * symeval.h: * symeval.h (DEFVAR_SYMVAL_FWD): * tooltalk.c: * tooltalk.c (print_tooltalk_message): * tooltalk.c (print_tooltalk_pattern): * ui-gtk.c (ffi_object_printer): * ui-gtk.c (emacs_gtk_object_printer): * ui-gtk.c (emacs_gtk_boxed_printer): * window.c (print_window): * window.c (free_window_mirror): * window.c (debug_print_window): * xemacs.def.in.in: (1) printing_unreadable_object -> printing_unreadable_object_fmt. (2) printing_unreadable_lcrecord -> printing_unreadable_lisp_object and fix up so it no longer requires an lcrecord. These previous changes eliminate most of the remaining places where the terms `lcrecord' and `lrecord' occurred outside of specialized code. (3) Fairly major change: Reduce the number of words in an lcrecord from 3 to 2. The third word consisted of a uid that duplicated the lrecord uid, and a single free bit, which was moved into the lrecord structure. This reduces the size of the `uid' slot from 21 bits to 20 bits. Arguably this isn't enough -- we could easily have more than 1,000,000 or so objects created in a session. The answer is (a) It doesn't really matter if we overflow the uid field because it's only used for debugging, to identify an object uniquely (or pretty much so). (b) If we cared about it overflowing and wanted to reduce this, we could make it so that cons, string, float and certain other frob-block types that never print out the uid simply don't store a uid in them and don't increment the lrecord_uid_counter. (4) In conjunction with (3), create new macro NORMAL_LISP_OBJECT_UID() and use it to abstract out the differences between NEWGC and old-GC in accessing the `uid' value from a "normal Lisp Object pointer". (5) In events.c, use zero_nonsized_lisp_object() in place of custom- written equivalent. In font-mgr.c use external_object_printer() in place of custom-written equivalents.
author Ben Wing <ben@xemacs.org>
date Sat, 13 Mar 2010 05:38:08 -0600
parents 576fb035e263
children 9fae6227ede5
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@c -*-texinfo-*-
@c This is part of the XEmacs Lisp Reference Manual.
@c Copyright (C) 1996 Ben Wing.
@c See the file lispref.texi for copying conditions.
@setfilename ../../info/databases.info
@node Databases, Processes, Range Tables, top
@chapter Databases
@cindex database

@defun databasep object
This function returns non-@code{nil} if @var{object} is a database.
@end defun

@menu
* Connecting to a Database::
* Working With a Database::
* Other Database Functions::
@end menu

@node Connecting to a Database
@section Connecting to a Database

@defun open-database file &optional type subtype access mode
This function opens database @var{file}, using database method
@var{type} and @var{subtype}, with access rights @var{access} and
permissions @var{mode}.  @var{access} can be any combination of @code{r}
@code{w} and @code{+}, for read, write, and creation flags.

@var{type} can have the value @code{'dbm} or @code{'berkeley-db} to
select the type of database file to use.  (Note:  XEmacs may not
support both of these types.)

For a @var{type} of @code{'dbm}, there are no subtypes, so
@var{subtype} should be @code{nil}.

For a @var{type} of @code{'berkeley-db}, the following subtypes are
available:  @code{'hash}, @code{'btree}, and @code{'recno}.  See the
manpages for the Berkeley DB functions for more information about these
types.
@end defun

@defun close-database database
This function closes database @var{database}.
@end defun

@defun database-live-p object
This function returns @code{t} if @var{object} is an active database, else
@code{nil}.
@end defun

@node Working With a Database
@section Working With a Database

@defun get-database key database &optional default
This function finds the value for @var{key} in @var{database}.  If there is no
corresponding value, @var{default} is returned (@code{nil} if @var{default} is
omitted).
@end defun

@defun map-database function database
This function maps @var{function} over entries in @var{database},
calling it with two args, each key and value in the database.
@end defun

@defun put-database key value database &optional replace
This function stores @var{key} and @var{value} in @var{database}.
If optional fourth arg @var{replace} is non-@code{nil}, replace any
existing entry in the database.
@end defun

@defun remove-database key database
This function removes @var{key} from @var{database}.
@end defun

@node Other Database Functions
@section Other Database Functions

@defun database-file-name database
This function returns the filename associated with @var{database}.
@end defun

@defun database-last-error &optional database
This function returns the last error associated with @var{database}.
@end defun

@defun database-subtype database
This function returns the subtype of @var{database}, if any.
@end defun

@defun database-type database
This function returns the type of @var{database}.
@end defun