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1 | @ignore |
2 | This file documents the user interface to the GNU History library. | |
3 | ||
775e241e | 4 | Copyright (C) 1988-2016 Free Software Foundation, Inc. |
b585a9fa EZ |
5 | Authored by Brian Fox and Chet Ramey. |
6 | ||
7 | Permission is granted to make and distribute verbatim copies of this manual | |
8 | provided the copyright notice and this permission notice are preserved on | |
9 | all copies. | |
10 | ||
11 | Permission is granted to process this file through Tex and print the | |
12 | results, provided the printed document carries copying permission notice | |
13 | identical to this one except for the removal of this paragraph (this | |
14 | paragraph not being relevant to the printed manual). | |
15 | ||
16 | Permission is granted to copy and distribute modified versions of this | |
17 | manual under the conditions for verbatim copying, provided also that the | |
18 | GNU Copyright statement is available to the distributee, and provided that | |
19 | the entire resulting derived work is distributed under the terms of a | |
20 | permission notice identical to this one. | |
21 | ||
22 | Permission is granted to copy and distribute translations of this manual | |
23 | into another language, under the above conditions for modified versions. | |
24 | @end ignore | |
25 | ||
26 | @node Programming with GNU History | |
27 | @chapter Programming with GNU History | |
28 | ||
29 | This chapter describes how to interface programs that you write | |
30 | with the @sc{gnu} History Library. | |
31 | It should be considered a technical guide. | |
32 | For information on the interactive use of @sc{gnu} History, @pxref{Using | |
33 | History Interactively}. | |
34 | ||
35 | @menu | |
36 | * Introduction to History:: What is the GNU History library for? | |
37 | * History Storage:: How information is stored. | |
38 | * History Functions:: Functions that you can use. | |
39 | * History Variables:: Variables that control behaviour. | |
40 | * History Programming Example:: Example of using the GNU History Library. | |
41 | @end menu | |
42 | ||
43 | @node Introduction to History | |
44 | @section Introduction to History | |
45 | ||
46 | Many programs read input from the user a line at a time. The @sc{gnu} | |
47 | History library is able to keep track of those lines, associate arbitrary | |
48 | data with each line, and utilize information from previous lines in | |
49 | composing new ones. | |
50 | ||
51 | The programmer using the History library has available functions | |
52 | for remembering lines on a history list, associating arbitrary data | |
53 | with a line, removing lines from the list, searching through the list | |
54 | for a line containing an arbitrary text string, and referencing any line | |
55 | in the list directly. In addition, a history @dfn{expansion} function | |
56 | is available which provides for a consistent user interface across | |
57 | different programs. | |
58 | ||
59 | The user using programs written with the History library has the | |
60 | benefit of a consistent user interface with a set of well-known | |
61 | commands for manipulating the text of previous lines and using that text | |
62 | in new commands. The basic history manipulation commands are similar to | |
63 | the history substitution provided by @code{csh}. | |
64 | ||
65 | If the programmer desires, he can use the Readline library, which | |
66 | includes some history manipulation by default, and has the added | |
67 | advantage of command line editing. | |
68 | ||
69 | Before declaring any functions using any functionality the History | |
70 | library provides in other code, an application writer should include | |
71 | the file @code{<readline/history.h>} in any file that uses the | |
72 | History library's features. It supplies extern declarations for all | |
73 | of the library's public functions and variables, and declares all of | |
74 | the public data structures. | |
75 | ||
76 | @node History Storage | |
77 | @section History Storage | |
78 | ||
79 | The history list is an array of history entries. A history entry is | |
80 | declared as follows: | |
81 | ||
82 | @example | |
83 | typedef void *histdata_t; | |
84 | ||
85 | typedef struct _hist_entry @{ | |
86 | char *line; | |
87 | char *timestamp; | |
88 | histdata_t data; | |
89 | @} HIST_ENTRY; | |
90 | @end example | |
91 | ||
92 | The history list itself might therefore be declared as | |
93 | ||
94 | @example | |
95 | HIST_ENTRY **the_history_list; | |
96 | @end example | |
97 | ||
98 | The state of the History library is encapsulated into a single structure: | |
99 | ||
100 | @example | |
101 | /* | |
102 | * A structure used to pass around the current state of the history. | |
103 | */ | |
104 | typedef struct _hist_state @{ | |
105 | HIST_ENTRY **entries; /* Pointer to the entries themselves. */ | |
106 | int offset; /* The location pointer within this array. */ | |
107 | int length; /* Number of elements within this array. */ | |
108 | int size; /* Number of slots allocated to this array. */ | |
109 | int flags; | |
110 | @} HISTORY_STATE; | |
111 | @end example | |
112 | ||
113 | If the flags member includes @code{HS_STIFLED}, the history has been | |
114 | stifled. | |
115 | ||
116 | @node History Functions | |
117 | @section History Functions | |
118 | ||
119 | This section describes the calling sequence for the various functions | |
120 | exported by the @sc{gnu} History library. | |
121 | ||
122 | @menu | |
123 | * Initializing History and State Management:: Functions to call when you | |
124 | want to use history in a | |
125 | program. | |
126 | * History List Management:: Functions used to manage the list | |
127 | of history entries. | |
128 | * Information About the History List:: Functions returning information about | |
129 | the history list. | |
130 | * Moving Around the History List:: Functions used to change the position | |
131 | in the history list. | |
132 | * Searching the History List:: Functions to search the history list | |
133 | for entries containing a string. | |
134 | * Managing the History File:: Functions that read and write a file | |
135 | containing the history list. | |
136 | * History Expansion:: Functions to perform csh-like history | |
137 | expansion. | |
138 | @end menu | |
139 | ||
140 | @node Initializing History and State Management | |
141 | @subsection Initializing History and State Management | |
142 | ||
143 | This section describes functions used to initialize and manage | |
144 | the state of the History library when you want to use the history | |
145 | functions in your program. | |
146 | ||
147 | @deftypefun void using_history (void) | |
148 | Begin a session in which the history functions might be used. This | |
149 | initializes the interactive variables. | |
150 | @end deftypefun | |
151 | ||
152 | @deftypefun {HISTORY_STATE *} history_get_history_state (void) | |
153 | Return a structure describing the current state of the input history. | |
154 | @end deftypefun | |
155 | ||
156 | @deftypefun void history_set_history_state (HISTORY_STATE *state) | |
157 | Set the state of the history list according to @var{state}. | |
158 | @end deftypefun | |
159 | ||
160 | @node History List Management | |
161 | @subsection History List Management | |
162 | ||
163 | These functions manage individual entries on the history list, or set | |
164 | parameters managing the list itself. | |
165 | ||
166 | @deftypefun void add_history (const char *string) | |
167 | Place @var{string} at the end of the history list. The associated data | |
168 | field (if any) is set to @code{NULL}. | |
cb41b9e7 TT |
169 | If the maximum number of history entries has been set using |
170 | @code{stifle_history()}, and the new number of history entries would exceed | |
171 | that maximum, the oldest history entry is removed. | |
b585a9fa EZ |
172 | @end deftypefun |
173 | ||
174 | @deftypefun void add_history_time (const char *string) | |
175 | Change the time stamp associated with the most recent history entry to | |
176 | @var{string}. | |
177 | @end deftypefun | |
178 | ||
179 | @deftypefun {HIST_ENTRY *} remove_history (int which) | |
180 | Remove history entry at offset @var{which} from the history. The | |
181 | removed element is returned so you can free the line, data, | |
182 | and containing structure. | |
183 | @end deftypefun | |
184 | ||
185 | @deftypefun {histdata_t} free_history_entry (HIST_ENTRY *histent) | |
186 | Free the history entry @var{histent} and any history library private | |
187 | data associated with it. Returns the application-specific data | |
188 | so the caller can dispose of it. | |
189 | @end deftypefun | |
190 | ||
191 | @deftypefun {HIST_ENTRY *} replace_history_entry (int which, const char *line, histdata_t data) | |
192 | Make the history entry at offset @var{which} have @var{line} and @var{data}. | |
193 | This returns the old entry so the caller can dispose of any | |
194 | application-specific data. In the case | |
195 | of an invalid @var{which}, a @code{NULL} pointer is returned. | |
196 | @end deftypefun | |
197 | ||
198 | @deftypefun void clear_history (void) | |
199 | Clear the history list by deleting all the entries. | |
200 | @end deftypefun | |
201 | ||
202 | @deftypefun void stifle_history (int max) | |
203 | Stifle the history list, remembering only the last @var{max} entries. | |
cb41b9e7 | 204 | The history list will contain only @var{max} entries at a time. |
b585a9fa EZ |
205 | @end deftypefun |
206 | ||
207 | @deftypefun int unstifle_history (void) | |
208 | Stop stifling the history. This returns the previously-set | |
209 | maximum number of history entries (as set by @code{stifle_history()}). | |
210 | The value is positive if the history was | |
211 | stifled, negative if it wasn't. | |
212 | @end deftypefun | |
213 | ||
214 | @deftypefun int history_is_stifled (void) | |
215 | Returns non-zero if the history is stifled, zero if it is not. | |
216 | @end deftypefun | |
217 | ||
218 | @node Information About the History List | |
219 | @subsection Information About the History List | |
220 | ||
221 | These functions return information about the entire history list or | |
222 | individual list entries. | |
223 | ||
224 | @deftypefun {HIST_ENTRY **} history_list (void) | |
225 | Return a @code{NULL} terminated array of @code{HIST_ENTRY *} which is the | |
226 | current input history. Element 0 of this list is the beginning of time. | |
227 | If there is no history, return @code{NULL}. | |
228 | @end deftypefun | |
229 | ||
230 | @deftypefun int where_history (void) | |
231 | Returns the offset of the current history element. | |
232 | @end deftypefun | |
233 | ||
234 | @deftypefun {HIST_ENTRY *} current_history (void) | |
235 | Return the history entry at the current position, as determined by | |
236 | @code{where_history()}. If there is no entry there, return a @code{NULL} | |
237 | pointer. | |
238 | @end deftypefun | |
239 | ||
240 | @deftypefun {HIST_ENTRY *} history_get (int offset) | |
cb41b9e7 TT |
241 | Return the history entry at position @var{offset}. |
242 | The range of valid | |
243 | values of @var{offset} starts at @code{history_base} and ends at | |
244 | @var{history_length} - 1 (@pxref{History Variables}). | |
245 | If there is no entry there, or if @var{offset} is outside the valid | |
246 | range, return a @code{NULL} pointer. | |
b585a9fa EZ |
247 | @end deftypefun |
248 | ||
249 | @deftypefun time_t history_get_time (HIST_ENTRY *entry) | |
250 | Return the time stamp associated with the history entry @var{entry}. | |
775e241e | 251 | If the timestamp is missing or invalid, return 0. |
b585a9fa EZ |
252 | @end deftypefun |
253 | ||
254 | @deftypefun int history_total_bytes (void) | |
255 | Return the number of bytes that the primary history entries are using. | |
256 | This function returns the sum of the lengths of all the lines in the | |
257 | history. | |
258 | @end deftypefun | |
259 | ||
260 | @node Moving Around the History List | |
261 | @subsection Moving Around the History List | |
262 | ||
263 | These functions allow the current index into the history list to be | |
264 | set or changed. | |
265 | ||
266 | @deftypefun int history_set_pos (int pos) | |
267 | Set the current history offset to @var{pos}, an absolute index | |
268 | into the list. | |
269 | Returns 1 on success, 0 if @var{pos} is less than zero or greater | |
270 | than the number of history entries. | |
271 | @end deftypefun | |
272 | ||
273 | @deftypefun {HIST_ENTRY *} previous_history (void) | |
274 | Back up the current history offset to the previous history entry, and | |
275 | return a pointer to that entry. If there is no previous entry, return | |
276 | a @code{NULL} pointer. | |
277 | @end deftypefun | |
278 | ||
279 | @deftypefun {HIST_ENTRY *} next_history (void) | |
775e241e TT |
280 | If the current history offset refers to a valid history entry, |
281 | increment the current history offset. | |
282 | If the possibly-incremented history offset refers to a valid history | |
283 | entry, return a pointer to that entry; | |
284 | otherwise, return a @code{BNULL} pointer. | |
b585a9fa EZ |
285 | @end deftypefun |
286 | ||
287 | @node Searching the History List | |
288 | @subsection Searching the History List | |
289 | @cindex History Searching | |
290 | ||
291 | These functions allow searching of the history list for entries containing | |
292 | a specific string. Searching may be performed both forward and backward | |
293 | from the current history position. The search may be @dfn{anchored}, | |
294 | meaning that the string must match at the beginning of the history entry. | |
295 | @cindex anchored search | |
296 | ||
297 | @deftypefun int history_search (const char *string, int direction) | |
298 | Search the history for @var{string}, starting at the current history offset. | |
299 | If @var{direction} is less than 0, then the search is through | |
300 | previous entries, otherwise through subsequent entries. | |
301 | If @var{string} is found, then | |
302 | the current history index is set to that history entry, and the value | |
303 | returned is the offset in the line of the entry where | |
304 | @var{string} was found. Otherwise, nothing is changed, and a -1 is | |
305 | returned. | |
306 | @end deftypefun | |
307 | ||
308 | @deftypefun int history_search_prefix (const char *string, int direction) | |
309 | Search the history for @var{string}, starting at the current history | |
310 | offset. The search is anchored: matching lines must begin with | |
311 | @var{string}. If @var{direction} is less than 0, then the search is | |
312 | through previous entries, otherwise through subsequent entries. | |
313 | If @var{string} is found, then the | |
314 | current history index is set to that entry, and the return value is 0. | |
315 | Otherwise, nothing is changed, and a -1 is returned. | |
316 | @end deftypefun | |
317 | ||
318 | @deftypefun int history_search_pos (const char *string, int direction, int pos) | |
319 | Search for @var{string} in the history list, starting at @var{pos}, an | |
320 | absolute index into the list. If @var{direction} is negative, the search | |
321 | proceeds backward from @var{pos}, otherwise forward. Returns the absolute | |
322 | index of the history element where @var{string} was found, or -1 otherwise. | |
323 | @end deftypefun | |
324 | ||
325 | @node Managing the History File | |
326 | @subsection Managing the History File | |
327 | ||
328 | The History library can read the history from and write it to a file. | |
329 | This section documents the functions for managing a history file. | |
330 | ||
331 | @deftypefun int read_history (const char *filename) | |
332 | Add the contents of @var{filename} to the history list, a line at a time. | |
333 | If @var{filename} is @code{NULL}, then read from @file{~/.history}. | |
334 | Returns 0 if successful, or @code{errno} if not. | |
335 | @end deftypefun | |
336 | ||
337 | @deftypefun int read_history_range (const char *filename, int from, int to) | |
338 | Read a range of lines from @var{filename}, adding them to the history list. | |
339 | Start reading at line @var{from} and end at @var{to}. | |
340 | If @var{from} is zero, start at the beginning. If @var{to} is less than | |
341 | @var{from}, then read until the end of the file. If @var{filename} is | |
342 | @code{NULL}, then read from @file{~/.history}. Returns 0 if successful, | |
343 | or @code{errno} if not. | |
344 | @end deftypefun | |
345 | ||
346 | @deftypefun int write_history (const char *filename) | |
347 | Write the current history to @var{filename}, overwriting @var{filename} | |
348 | if necessary. | |
349 | If @var{filename} is @code{NULL}, then write the history list to | |
350 | @file{~/.history}. | |
351 | Returns 0 on success, or @code{errno} on a read or write error. | |
352 | @end deftypefun | |
353 | ||
354 | @deftypefun int append_history (int nelements, const char *filename) | |
355 | Append the last @var{nelements} of the history list to @var{filename}. | |
356 | If @var{filename} is @code{NULL}, then append to @file{~/.history}. | |
357 | Returns 0 on success, or @code{errno} on a read or write error. | |
358 | @end deftypefun | |
359 | ||
360 | @deftypefun int history_truncate_file (const char *filename, int nlines) | |
361 | Truncate the history file @var{filename}, leaving only the last | |
362 | @var{nlines} lines. | |
363 | If @var{filename} is @code{NULL}, then @file{~/.history} is truncated. | |
364 | Returns 0 on success, or @code{errno} on failure. | |
365 | @end deftypefun | |
366 | ||
367 | @node History Expansion | |
368 | @subsection History Expansion | |
369 | ||
370 | These functions implement history expansion. | |
371 | ||
372 | @deftypefun int history_expand (char *string, char **output) | |
373 | Expand @var{string}, placing the result into @var{output}, a pointer | |
374 | to a string (@pxref{History Interaction}). Returns: | |
375 | @table @code | |
376 | @item 0 | |
377 | If no expansions took place (or, if the only change in | |
378 | the text was the removal of escape characters preceding the history expansion | |
379 | character); | |
380 | @item 1 | |
381 | if expansions did take place; | |
382 | @item -1 | |
383 | if there was an error in expansion; | |
384 | @item 2 | |
385 | if the returned line should be displayed, but not executed, | |
386 | as with the @code{:p} modifier (@pxref{Modifiers}). | |
387 | @end table | |
388 | ||
775e241e | 389 | If an error occurred in expansion, then @var{output} contains a descriptive |
b585a9fa EZ |
390 | error message. |
391 | @end deftypefun | |
392 | ||
393 | @deftypefun {char *} get_history_event (const char *string, int *cindex, int qchar) | |
394 | Returns the text of the history event beginning at @var{string} + | |
395 | @var{*cindex}. @var{*cindex} is modified to point to after the event | |
396 | specifier. At function entry, @var{cindex} points to the index into | |
397 | @var{string} where the history event specification begins. @var{qchar} | |
398 | is a character that is allowed to end the event specification in addition | |
399 | to the ``normal'' terminating characters. | |
400 | @end deftypefun | |
401 | ||
402 | @deftypefun {char **} history_tokenize (const char *string) | |
403 | Return an array of tokens parsed out of @var{string}, much as the | |
404 | shell might. The tokens are split on the characters in the | |
405 | @var{history_word_delimiters} variable, | |
cb41b9e7 | 406 | and shell quoting conventions are obeyed as described below. |
b585a9fa EZ |
407 | @end deftypefun |
408 | ||
409 | @deftypefun {char *} history_arg_extract (int first, int last, const char *string) | |
410 | Extract a string segment consisting of the @var{first} through @var{last} | |
411 | arguments present in @var{string}. Arguments are split using | |
412 | @code{history_tokenize}. | |
413 | @end deftypefun | |
414 | ||
415 | @node History Variables | |
416 | @section History Variables | |
417 | ||
418 | This section describes the externally-visible variables exported by | |
419 | the @sc{gnu} History Library. | |
420 | ||
421 | @deftypevar int history_base | |
422 | The logical offset of the first entry in the history list. | |
423 | @end deftypevar | |
424 | ||
425 | @deftypevar int history_length | |
426 | The number of entries currently stored in the history list. | |
427 | @end deftypevar | |
428 | ||
429 | @deftypevar int history_max_entries | |
430 | The maximum number of history entries. This must be changed using | |
431 | @code{stifle_history()}. | |
432 | @end deftypevar | |
433 | ||
434 | @deftypevar int history_write_timestamps | |
435 | If non-zero, timestamps are written to the history file, so they can be | |
436 | preserved between sessions. The default value is 0, meaning that | |
437 | timestamps are not saved. | |
cc88a640 JK |
438 | |
439 | The current timestamp format uses the value of @var{history_comment_char} | |
440 | to delimit timestamp entries in the history file. If that variable does | |
441 | not have a value (the default), timestamps will not be written. | |
b585a9fa EZ |
442 | @end deftypevar |
443 | ||
444 | @deftypevar char history_expansion_char | |
445 | The character that introduces a history event. The default is @samp{!}. | |
446 | Setting this to 0 inhibits history expansion. | |
447 | @end deftypevar | |
448 | ||
449 | @deftypevar char history_subst_char | |
450 | The character that invokes word substitution if found at the start of | |
451 | a line. The default is @samp{^}. | |
452 | @end deftypevar | |
453 | ||
454 | @deftypevar char history_comment_char | |
455 | During tokenization, if this character is seen as the first character | |
456 | of a word, then it and all subsequent characters up to a newline are | |
457 | ignored, suppressing history expansion for the remainder of the line. | |
458 | This is disabled by default. | |
459 | @end deftypevar | |
460 | ||
461 | @deftypevar {char *} history_word_delimiters | |
462 | The characters that separate tokens for @code{history_tokenize()}. | |
463 | The default value is @code{" \t\n()<>;&|"}. | |
464 | @end deftypevar | |
465 | ||
466 | @deftypevar {char *} history_search_delimiter_chars | |
467 | The list of additional characters which can delimit a history search | |
468 | string, in addition to space, TAB, @samp{:} and @samp{?} in the case of | |
469 | a substring search. The default is empty. | |
470 | @end deftypevar | |
471 | ||
472 | @deftypevar {char *} history_no_expand_chars | |
473 | The list of characters which inhibit history expansion if found immediately | |
474 | following @var{history_expansion_char}. The default is space, tab, newline, | |
475 | carriage return, and @samp{=}. | |
476 | @end deftypevar | |
477 | ||
478 | @deftypevar int history_quotes_inhibit_expansion | |
cb41b9e7 TT |
479 | If non-zero, the history expansion code implements shell-like quoting: |
480 | single-quoted words are not scanned for the history expansion | |
481 | character or the history comment character, and double-quoted words may | |
482 | have history expansion performed, since single quotes are not special | |
483 | within double quotes. | |
484 | The default value is 0. | |
485 | @end deftypevar | |
486 | ||
487 | @deftypevar int history_quoting_state | |
488 | An application may set this variable to indicate that the current line | |
489 | being expanded is subject to existing quoting. If set to @samp{'}, the | |
490 | history expansion function will assume that the line is single-quoted and | |
491 | inhibit expansion until it reads an unquoted closing single quote; if set | |
492 | to @samp{"}, history expansion will assume the line is double quoted until | |
493 | it reads an unquoted closing double quote. If set to zero, the default, | |
494 | the history expansion function will assume the line is not quoted and | |
495 | treat quote characters within the line as described above. | |
496 | This is only effective if @var{history_quotes_inhibit_expansion} is set. | |
b585a9fa EZ |
497 | @end deftypevar |
498 | ||
499 | @deftypevar {rl_linebuf_func_t *} history_inhibit_expansion_function | |
500 | This should be set to the address of a function that takes two arguments: | |
501 | a @code{char *} (@var{string}) | |
502 | and an @code{int} index into that string (@var{i}). | |
503 | It should return a non-zero value if the history expansion starting at | |
504 | @var{string[i]} should not be performed; zero if the expansion should | |
505 | be done. | |
506 | It is intended for use by applications like Bash that use the history | |
507 | expansion character for additional purposes. | |
508 | By default, this variable is set to @code{NULL}. | |
509 | @end deftypevar | |
510 | ||
511 | @node History Programming Example | |
512 | @section History Programming Example | |
513 | ||
514 | The following program demonstrates simple use of the @sc{gnu} History Library. | |
515 | ||
516 | @smallexample | |
517 | #include <stdio.h> | |
518 | #include <readline/history.h> | |
519 | ||
520 | main (argc, argv) | |
521 | int argc; | |
522 | char **argv; | |
523 | @{ | |
524 | char line[1024], *t; | |
525 | int len, done = 0; | |
526 | ||
527 | line[0] = 0; | |
528 | ||
529 | using_history (); | |
530 | while (!done) | |
531 | @{ | |
532 | printf ("history$ "); | |
533 | fflush (stdout); | |
534 | t = fgets (line, sizeof (line) - 1, stdin); | |
535 | if (t && *t) | |
536 | @{ | |
537 | len = strlen (t); | |
538 | if (t[len - 1] == '\n') | |
539 | t[len - 1] = '\0'; | |
540 | @} | |
541 | ||
542 | if (!t) | |
543 | strcpy (line, "quit"); | |
544 | ||
545 | if (line[0]) | |
546 | @{ | |
547 | char *expansion; | |
548 | int result; | |
549 | ||
550 | result = history_expand (line, &expansion); | |
551 | if (result) | |
552 | fprintf (stderr, "%s\n", expansion); | |
553 | ||
554 | if (result < 0 || result == 2) | |
555 | @{ | |
556 | free (expansion); | |
557 | continue; | |
558 | @} | |
559 | ||
560 | add_history (expansion); | |
561 | strncpy (line, expansion, sizeof (line) - 1); | |
562 | free (expansion); | |
563 | @} | |
564 | ||
565 | if (strcmp (line, "quit") == 0) | |
566 | done = 1; | |
567 | else if (strcmp (line, "save") == 0) | |
568 | write_history ("history_file"); | |
569 | else if (strcmp (line, "read") == 0) | |
570 | read_history ("history_file"); | |
571 | else if (strcmp (line, "list") == 0) | |
572 | @{ | |
573 | register HIST_ENTRY **the_list; | |
574 | register int i; | |
575 | ||
576 | the_list = history_list (); | |
577 | if (the_list) | |
578 | for (i = 0; the_list[i]; i++) | |
579 | printf ("%d: %s\n", i + history_base, the_list[i]->line); | |
580 | @} | |
581 | else if (strncmp (line, "delete", 6) == 0) | |
582 | @{ | |
583 | int which; | |
584 | if ((sscanf (line + 6, "%d", &which)) == 1) | |
585 | @{ | |
586 | HIST_ENTRY *entry = remove_history (which); | |
587 | if (!entry) | |
588 | fprintf (stderr, "No such entry %d\n", which); | |
589 | else | |
590 | @{ | |
591 | free (entry->line); | |
592 | free (entry); | |
593 | @} | |
594 | @} | |
595 | else | |
596 | @{ | |
597 | fprintf (stderr, "non-numeric arg given to `delete'\n"); | |
598 | @} | |
599 | @} | |
600 | @} | |
601 | @} | |
602 | @end smallexample |