Mercurial > hg > xemacs-beta

comparison man/lispref/variables.texi @ 5361:62b9ef1ed4ac

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Change "special form" to "special operator" in the manuals, too 2011-03-01 Aidan Kehoe <kehoea@parhasard.net> * lispref/commands.texi (Using Interactive): * lispref/compile.texi (Eval During Compile): * lispref/compile.texi (Compiled-Function Objects): * lispref/control.texi (Sequencing): * lispref/control.texi (Conditionals): * lispref/control.texi (Combining Conditions): * lispref/control.texi (Iteration): * lispref/control.texi (Catch and Throw): * lispref/control.texi (Handling Errors): * lispref/control.texi (Cleanups): * lispref/display.texi (Temporary Displays): * lispref/eval.texi (Quoting): * lispref/eval.texi (Multiple values): * lispref/frames.texi (Input Focus): * lispref/functions.texi (Argument List): * lispref/functions.texi (Defining Functions): * lispref/functions.texi (Anonymous Functions): * lispref/internationalization.texi (Level 3 Primitives): * lispref/internationalization.texi (Domain Specification): * lispref/intro.texi (A Sample Function Description): * lispref/intro.texi (A Sample Variable Description): * lispref/lists.texi (Sets And Lists): * lispref/macros.texi (Defining Macros): * lispref/macros.texi (Backquote): * lispref/positions.texi (Excursions): * lispref/positions.texi (Narrowing): * lispref/searching.texi (Saving Match Data): * lispref/sequences.texi (Sequence Functions): * lispref/sequences.texi (Array Functions): * lispref/specifiers.texi (Adding Specifications): * lispref/variables.texi (Local Variables): * lispref/variables.texi (Defining Variables): * lispref/variables.texi (Setting Variables): * lispref/variables.texi (Default Value): * lispref/windows.texi (Selecting Windows): * lispref/windows.texi (Window Configurations): No longer use @defspec, since we no longer use the term "special form"; instead use @deffn {Special Operator}. Unfortunately there's no way in texinfo to redefine @defspec in one place.
author Aidan Kehoe <kehoea@parhasard.net>
date Tue, 01 Mar 2011 14:18:45 +0000
parents 755ae5b97edb
children 9fae6227ede5
comparison
equal deleted inserted replaced
5359:f5a5501814f5 5361:62b9ef1ed4ac
166 binding. 166 binding.
167 167
168 The special operators @code{let} and @code{let*} exist to create 168 The special operators @code{let} and @code{let*} exist to create
169 local bindings. 169 local bindings.
170 170
171 @defspec let (bindings@dots{}) forms@dots{} 171 @deffn {Special Operator} let (bindings@dots{}) forms@dots{}
172 This special operator binds variables according to @var{bindings} and then 172 This special operator binds variables according to @var{bindings} and then
173 evaluates all of the @var{forms} in textual order. The @code{let}-form 173 evaluates all of the @var{forms} in textual order. The @code{let}-form
174 returns the value of the last form in @var{forms}. 174 returns the value of the last form in @var{forms}.
175 175
176 Each of the @var{bindings} is either @w{(i) a} symbol, in which case 176 Each of the @var{bindings} is either @w{(i) a} symbol, in which case
194 (Z Y)) 194 (Z Y))
195 (list Y Z)) 195 (list Y Z))
196 @result{} (1 2) 196 @result{} (1 2)
197 @end group 197 @end group
198 @end example 198 @end example
199 @end defspec 199 @end deffn
200 200
201 @defspec let* (bindings@dots{}) forms@dots{} 201 @deffn {Special Operator} let* (bindings@dots{}) forms@dots{}
202 This special operator is like @code{let}, but it binds each variable right 202 This special operator is like @code{let}, but it binds each variable right
203 after computing its local value, before computing the local value for 203 after computing its local value, before computing the local value for
204 the next variable. Therefore, an expression in @var{bindings} can 204 the next variable. Therefore, an expression in @var{bindings} can
205 reasonably refer to the preceding symbols bound in this @code{let*} 205 reasonably refer to the preceding symbols bound in this @code{let*}
206 form. Compare the following example with the example above for 206 form. Compare the following example with the example above for
216 (Z Y)) ; @r{Use the just-established value of @code{Y}.} 216 (Z Y)) ; @r{Use the just-established value of @code{Y}.}
217 (list Y Z)) 217 (list Y Z))
218 @result{} (1 1) 218 @result{} (1 1)
219 @end group 219 @end group
220 @end example 220 @end example
221 @end defspec 221 @end deffn
222 222
223 Here is a complete list of the other facilities that create local 223 Here is a complete list of the other facilities that create local
224 bindings: 224 bindings:
225 225
226 @itemize @bullet 226 @itemize @bullet
401 @code{defconst} would override any prior value when the library is 401 @code{defconst} would override any prior value when the library is
402 loaded. Users would like to be able to set user options in their init 402 loaded. Users would like to be able to set user options in their init
403 files, and override the default values given in the definitions. For 403 files, and override the default values given in the definitions. For
404 this reason, user options must be defined with @code{defvar}. 404 this reason, user options must be defined with @code{defvar}.
405 405
406 @defspec defvar symbol [value [doc-string]] 406 @deffn {Special Operator} defvar symbol [value [doc-string]]
407 This special operator defines @var{symbol} as a value and initializes it. 407 This special operator defines @var{symbol} as a value and initializes it.
408 The definition informs a person reading your code that @var{symbol} is 408 The definition informs a person reading your code that @var{symbol} is
409 used as a variable that programs are likely to set or change. It is 409 used as a variable that programs are likely to set or change. It is
410 also used for all user option variables except in the preloaded parts of 410 also used for all user option variables except in the preloaded parts of
411 XEmacs. Note that @var{symbol} is not evaluated; the symbol to be 411 XEmacs. Note that @var{symbol} is not evaluated; the symbol to be
489 @end group 489 @end group
490 @end example 490 @end example
491 491
492 The @code{defvar} form returns @var{symbol}, but it is normally used 492 The @code{defvar} form returns @var{symbol}, but it is normally used
493 at top level in a file where its value does not matter. 493 at top level in a file where its value does not matter.
494 @end defspec 494 @end deffn
495 495
496 @defspec defconst symbol [value [doc-string]] 496 @deffn {Special Operator} defconst symbol [value [doc-string]]
497 This special operator defines @var{symbol} as a value and initializes it. 497 This special operator defines @var{symbol} as a value and initializes it.
498 It informs a person reading your code that @var{symbol} has a global 498 It informs a person reading your code that @var{symbol} has a global
499 value, established here, that will not normally be changed or locally 499 value, established here, that will not normally be changed or locally
500 bound by the execution of the program. The user, however, may be 500 bound by the execution of the program. The user, however, may be
501 welcome to change it. Note that @var{symbol} is not evaluated; the 501 welcome to change it. Note that @var{symbol} is not evaluated; the
528 @group 528 @group
529 pi 529 pi
530 @result{} 3 530 @result{} 3
531 @end group 531 @end group
532 @end example 532 @end example
533 @end defspec 533 @end deffn
534 534
535 @defun user-variable-p variable 535 @defun user-variable-p variable
536 @cindex user option 536 @cindex user option
537 This function returns @code{t} if @var{variable} is a user option---a 537 This function returns @code{t} if @var{variable} is a user option---a
538 variable intended to be set by the user for customization---and 538 variable intended to be set by the user for customization---and
613 613
614 The usual way to change the value of a variable is with the special 614 The usual way to change the value of a variable is with the special
615 form @code{setq}. When you need to compute the choice of variable at 615 form @code{setq}. When you need to compute the choice of variable at
616 run time, use the function @code{set}. 616 run time, use the function @code{set}.
617 617
618 @defspec setq [symbol form]@dots{} 618 @deffn {Special Operator} setq [symbol form]@dots{}
619 This special operator is the most common method of changing a variable's 619 This special operator is the most common method of changing a variable's
620 value. Each @var{symbol} is given a new value, which is the result of 620 value. Each @var{symbol} is given a new value, which is the result of
621 evaluating the corresponding @var{form}. The most-local existing 621 evaluating the corresponding @var{form}. The most-local existing
622 binding of the symbol is changed. 622 binding of the symbol is changed.
623 623
653 (setq x 10 ; @r{Notice that @code{x} is set before} 653 (setq x 10 ; @r{Notice that @code{x} is set before}
654 y (1+ x)) ; @r{the value of @code{y} is computed.} 654 y (1+ x)) ; @r{the value of @code{y} is computed.}
655 @result{} 11 655 @result{} 11
656 @end group 656 @end group
657 @end example 657 @end example
658 @end defspec 658 @end deffn
659 659
660 @defun set symbol value 660 @defun set symbol value
661 This function sets @var{symbol}'s value to @var{value}, then returns 661 This function sets @var{symbol}'s value to @var{value}, then returns
662 @var{value}. Since @code{set} is a function, the expression written for 662 @var{value}. Since @code{set} is a function, the expression written for
663 @var{symbol} is evaluated to obtain the symbol to set. 663 @var{symbol} is evaluated to obtain the symbol to set.
1251 1251
1252 @code{default-boundp} is to @code{default-value} as @code{boundp} is to 1252 @code{default-boundp} is to @code{default-value} as @code{boundp} is to
1253 @code{symbol-value}. 1253 @code{symbol-value}.
1254 @end defun 1254 @end defun
1255 1255
1256 @defspec setq-default symbol value 1256 @deffn {Special Operator} setq-default symbol value
1257 This sets the default value of @var{symbol} to @var{value}. It does not 1257 This sets the default value of @var{symbol} to @var{value}. It does not
1258 evaluate @var{symbol}, but does evaluate @var{value}. The value of the 1258 evaluate @var{symbol}, but does evaluate @var{value}. The value of the
1259 @code{setq-default} form is @var{value}. 1259 @code{setq-default} form is @var{value}.
1260 1260
1261 If a @var{symbol} is not buffer-local for the current buffer, and is not 1261 If a @var{symbol} is not buffer-local for the current buffer, and is not
1312 @result{} value-in-foo 1312 @result{} value-in-foo
1313 (default-value 'local) 1313 (default-value 'local)
1314 @result{} another-default 1314 @result{} another-default
1315 @end group 1315 @end group
1316 @end example 1316 @end example
1317 @end defspec 1317 @end deffn
1318 1318
1319 @defun set-default symbol value 1319 @defun set-default symbol value
1320 This function is like @code{setq-default}, except that @var{symbol} is 1320 This function is like @code{setq-default}, except that @var{symbol} is
1321 evaluated. 1321 evaluated.
1322 1322