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[xemacs-hg @ 2005-01-21 09:43:09 by aidan] Rename "functions" node to "functions and commands," move the definition of a command further up the list of types of functions, give information on a trivial (interactive) declaration, and cross-reference to the key binding detail. Cf. 87vf9wgd08.fsf@tleepslib.sk.tsukuba.ac.jp (comp.emacs.xemacs, 2005-01-18).
author aidan
date Fri, 21 Jan 2005 09:43:12 +0000
parents 576fb035e263
children 755ae5b97edb
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2491:876c400e58d7 2492:6780963faf78
1 @c -*-texinfo-*- 1 @c -*-texinfo-*-
2 @c This is part of the XEmacs Lisp Reference Manual. 2 @c This is part of the XEmacs Lisp Reference Manual.
3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. 3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
4 @c See the file lispref.texi for copying conditions. 4 @c See the file lispref.texi for copying conditions.
5 @setfilename ../../info/functions.info 5 @setfilename ../../info/functions.info
6 @node Functions, Macros, Variables, Top 6 @node Functions and Commands, Macros, Variables, Top
7 @chapter Functions 7 @chapter Functions and Commands
8 8
9 A Lisp program is composed mainly of Lisp functions. This chapter 9 A Lisp program is composed mainly of Lisp functions. This chapter
10 explains what functions are, how they accept arguments, and how to 10 explains what functions are, how they accept arguments, and how to
11 define them. 11 define them.
12 12
43 In XEmacs Lisp, a @dfn{function} is anything that can be applied to 43 In XEmacs Lisp, a @dfn{function} is anything that can be applied to
44 arguments in a Lisp program. In some cases, we use it more 44 arguments in a Lisp program. In some cases, we use it more
45 specifically to mean a function written in Lisp. Special forms and 45 specifically to mean a function written in Lisp. Special forms and
46 macros are not functions. 46 macros are not functions.
47 47
48 @item command
49 @cindex command
50
51 A @dfn{command} is a possible definition for a key sequence---we count
52 mouse events and menu accesses as key sequences for this purpose. More
53 formally, within XEmacs lisp, a command is something that
54 @code{command-execute} can invoke.
55
56 Some functions are commands; a function written in Lisp is a command if
57 it contains an interactive declaration. A trivial interactive
58 declaration is a line @code{(interactive)} immediately after the
59 documentation string. For more complex examples, with prompting and
60 completion, see @xref{Defining Commands}. Such a function can be called
61 from Lisp expressions like other functions; in this case, the fact that
62 the function is a command makes no difference.
63
64 Keyboard macros (strings and vectors) are commands also, even though
65 they are not functions. A symbol is a command if its function
66 definition is a command; such symbols can be invoked with @kbd{M-x}.
67 The symbol is a function as well if the definition is a function.
68
69 In the case where you want to call a command in reaction to a
70 user-generated event, you'll need to bind it to that event. For how to
71 do this, see @xref{Key Binding Commands}.
72 @xref{Command Overview}.
73
74 @item keystroke command
75 @cindex keystroke command
76 A @dfn{keystroke command} is a command that is bound to a key sequence
77 (typically one to three keystrokes). The distinction is made here
78 merely to avoid confusion with the meaning of ``command'' in non-Emacs
79 editors; for Lisp programs, the distinction is normally unimportant.
80
48 @item primitive 81 @item primitive
49 @cindex primitive 82 @cindex primitive
50 @cindex subr 83 @cindex subr
51 @cindex built-in function 84 @cindex built-in function
52 A @dfn{primitive} is a function callable from Lisp that is written in C, 85 A @dfn{primitive} is a function callable from Lisp that is written in C,
81 differs from a function in that it translates a Lisp expression that you 114 differs from a function in that it translates a Lisp expression that you
82 write into an equivalent expression to be evaluated instead of the 115 write into an equivalent expression to be evaluated instead of the
83 original expression. Macros enable Lisp programmers to do the sorts of 116 original expression. Macros enable Lisp programmers to do the sorts of
84 things that special forms can do. @xref{Macros}, for how to define and 117 things that special forms can do. @xref{Macros}, for how to define and
85 use macros. 118 use macros.
86
87 @item command
88 @cindex command
89 A @dfn{command} is an object that @code{command-execute} can invoke; it
90 is a possible definition for a key sequence. Some functions are
91 commands; a function written in Lisp is a command if it contains an
92 interactive declaration (@pxref{Defining Commands}). Such a function
93 can be called from Lisp expressions like other functions; in this case,
94 the fact that the function is a command makes no difference.
95
96 Keyboard macros (strings and vectors) are commands also, even though
97 they are not functions. A symbol is a command if its function
98 definition is a command; such symbols can be invoked with @kbd{M-x}.
99 The symbol is a function as well if the definition is a function.
100 @xref{Command Overview}.
101
102 @item keystroke command
103 @cindex keystroke command
104 A @dfn{keystroke command} is a command that is bound to a key sequence
105 (typically one to three keystrokes). The distinction is made here
106 merely to avoid confusion with the meaning of ``command'' in non-Emacs
107 editors; for Lisp programs, the distinction is normally unimportant.
108 119
109 @item compiled function 120 @item compiled function
110 A @dfn{compiled function} is a function that has been compiled by the 121 A @dfn{compiled function} is a function that has been compiled by the
111 byte compiler. @xref{Compiled-Function Type}. 122 byte compiler. @xref{Compiled-Function Type}.
112 @end table 123 @end table