1library(n) Tcl Built-In Commands library(n)
2______________________________________________________________________________
6
8 auto_execok, auto_import, auto_load, auto_mkindex, auto_mkindex_old,
9 auto_qualify, auto_reset, tcl_findLibrary, parray, tcl_endOfWord,
10 tcl_startOfNextWord, tcl_startOfPreviousWord, tcl_wordBreakAfter,
11 tcl_wordBreakBefore - standard library of Tcl procedures
12
14 auto_execok cmd
15 auto_import pattern
16 auto_load cmd
17 auto_mkindex dir pattern pattern ...
18 auto_mkindex_old dir pattern pattern ...
19 auto_qualify command namespace
20 auto_reset
21 tcl_findLibrary basename version patch initScript enVarName varName
22 parray arrayName
23 tcl_endOfWord str start │
24 tcl_startOfNextWord str start │
25 tcl_startOfPreviousWord str start │
26 tcl_wordBreakAfter str start │
27 tcl_wordBreakBefore str start │
28_________________________________________________________________
29
32 Tcl includes a library of Tcl procedures for commonly-needed functions.
33 The procedures defined in the Tcl library are generic ones suitable for
34 use by many different applications. The location of the Tcl library is
35 returned by the info library command. In addition to the Tcl library,
36 each application will normally have its own library of support proce‐
37 dures as well; the location of this library is normally given by the
38 value of the $app_library global variable, where app is the name of the
39 application. For example, the location of the Tk library is kept in
40 the variable $tk_library.
41 To access the procedures in the Tcl library, an application should
43 source the file init.tcl in the library, for example with the Tcl com‐
44 mand
45 source [file join [info library] init.tcl]
46 If the library procedure Tcl_Init is invoked from an application's
47 Tcl_AppInit procedure, this happens automatically. The code in
48 init.tcl will define the unknown procedure and arrange for the other
49 procedures to be loaded on-demand using the auto-load mechanism defined
50 below.
51
54 The following procedures are provided in the Tcl library:
55 auto_execok cmd
57 Determines whether there is an executable file or shell builtin
58 by the name cmd. If so, it returns a list of arguments to be
59 passed to exec to execute the executable file or shell builtin
60 named by cmd. If not, it returns an empty string. This command
61 examines the directories in the current search path (given by
62 the PATH environment variable) in its search for an executable
63 file named cmd. On Windows platforms, the search is expanded
64 with the same directories and file extensions as used by exec.
65 Auto_exec remembers information about previous searches in an
66 array named auto_execs; this avoids the path search in future
67 calls for the same cmd. The command auto_reset may be used to
68 force auto_execok to forget its cached information.
69 auto_import pattern
71 Auto_import is invoked during namespace import to see if the
72 imported commands specified by pattern reside in an autoloaded
73 library. If so, the commands are loaded so that they will be
74 available to the interpreter for creating the import links. If
75 the commands do not reside in an autoloaded library, auto_import
76 does nothing. The pattern matching is performed according to
77 the matching rules of namespace import.
78 auto_load cmd
80 This command attempts to load the definition for a Tcl command
81 named cmd. To do this, it searches an auto-load path, which is
82 a list of one or more directories. The auto-load path is given
83 by the global variable $auto_path if it exists. If there is no
84 $auto_path variable, then the TCLLIBPATH environment variable is
85 used, if it exists. Otherwise the auto-load path consists of
86 just the Tcl library directory. Within each directory in the
87 auto-load path there must be a file tclIndex that describes one
88 or more commands defined in that directory and a script to eval‐
89 uate to load each of the commands. The tclIndex file should be
90 generated with the auto_mkindex command. If cmd is found in an
91 index file, then the appropriate script is evaluated to create
92 the command. The auto_load command returns 1 if cmd was suc‐
93 cessfully created. The command returns 0 if there was no index
94 entry for cmd or if the script didn't actually define cmd (e.g.
95 because index information is out of date). If an error occurs
96 while processing the script, then that error is returned.
97 Auto_load only reads the index information once and saves it in
98 the array auto_index; future calls to auto_load check for cmd
99 in the array rather than re-reading the index files. The cached
100 index information may be deleted with the command auto_reset.
101 This will force the next auto_load command to reload the index
102 database from disk.
103 auto_mkindex dir pattern pattern ...
105 Generates an index suitable for use by auto_load. The command
106 searches dir for all files whose names match any of the pattern
107 arguments (matching is done with the glob command), generates an
108 index of all the Tcl command procedures defined in all the
109 matching files, and stores the index information in a file named
110 tclIndex in dir. If no pattern is given a pattern of *.tcl will
111 be assumed. For example, the command
112 auto_mkindex foo *.tcl
113 will read all the .tcl files in subdirectory foo and generate a
115 new index file foo/tclIndex.
116 Auto_mkindex parses the Tcl scripts by sourcing them into a
118 slave interpreter and monitoring the proc and namespace commands
119 that are executed. Extensions can use the (undocumented)
120 auto_mkindex_parser package to register other commands that can
121 contribute to the auto_load index. You will have to read through
122 auto.tcl to see how this works.
123 Auto_mkindex_old parses the Tcl scripts in a relatively unso‐
125 phisticated way: if any line contains the word proc as its
126 first characters then it is assumed to be a procedure definition
127 and the next word of the line is taken as the procedure's name.
128 Procedure definitions that don't appear in this way (e.g. they
129 have spaces before the proc) will not be indexed. If your
130 script contains "dangerous" code, such as global initialization
131 code or procedure names with special characters like $, *, [ or
132 ], you are safer using auto_mkindex_old.
133 auto_reset
135 Destroys all the information cached by auto_execok and
136 auto_load. This information will be re-read from disk the next
137 time it is needed. Auto_reset also deletes any procedures
138 listed in the auto-load index, so that fresh copies of them will
139 be loaded the next time that they're used.
140 auto_qualify command namespace
142 Computes a list of fully qualified names for command. This list
143 mirrors the path a standard Tcl interpreter follows for command
144 lookups: first it looks for the command in the current names‐
145 pace, and then in the global namespace. Accordingly, if command
146 is relative and namespace is not ::, the list returned has two
147 elements: command scoped by namespace, as if it were a command
148 in the namespace namespace; and command as if it were a command
149 in the global namespace. Otherwise, if either command is abso‐
150 lute (it begins with ::), or namespace is ::, the list contains
151 only command as if it were a command in the global namespace.
152 Auto_qualify is used by the auto-loading facilities in Tcl, both
154 for producing auto-loading indexes such as pkgIndex.tcl, and for
155 performing the actual auto-loading of functions at runtime.
156 tcl_findLibrary basename version patch initScript enVarName varName
158 This is a standard search procedure for use by extensions during
159 their initialization. They call this procedure to look for
160 their script library in several standard directories. The last
161 component of the name of the library directory is normally base‐
162 nameversion (e.g., tk8.0), but it might be "library" when in the
163 build hierarchies. The initScript file will be sourced into the
164 interpreter once it is found. The directory in which this file
165 is found is stored into the global variable varName. If this
166 variable is already defined (e.g., by C code during application
167 initialization) then no searching is done. Otherwise the search
168 looks in these directories: the directory named by the environ‐
169 ment variable enVarName; relative to the Tcl library directory;
170 relative to the executable file in the standard installation bin
171 or bin/arch directory; relative to the executable file in the
172 current build tree; relative to the executable file in a paral‐
173 lel build tree.
174 parray arrayName
176 Prints on standard output the names and values of all the ele‐
177 ments in the array arrayName. ArrayName must be an array acces‐
178 sible to the caller of parray. It may be either local or
179 global.
180 tcl_endOfWord str start
182 Returns the index of the first end-of-word location that occurs │
183 after a starting index start in the string str. An end-of-word │
184 location is defined to be the first non-word character following │
185 the first word character after the starting point. Returns -1 │
186 if there are no more end-of-word locations after the starting │
187 point. See the description of tcl_wordchars and tcl_nonword‐ │
188 chars below for more details on how Tcl determines which charac‐ │
189 ters are word characters. │
190 tcl_startOfNextWord str start │
192 Returns the index of the first start-of-word location that │
193 occurs after a starting index start in the string str. A start- │
194 of-word location is defined to be the first word character fol‐ │
195 lowing a non-word character. Returns -1 if there are no more │
196 start-of-word locations after the starting point. │
197 tcl_startOfPreviousWord str start │
199 Returns the index of the first start-of-word location that │
200 occurs before a starting index start in the string str. Returns │
201 -1 if there are no more start-of-word locations before the │
202 starting point. │
203 tcl_wordBreakAfter str start │
205 Returns the index of the first word boundary after the starting │
206 index start in the string str. Returns -1 if there are no more │
207 boundaries after the starting point in the given string. The │
208 index returned refers to the second character of the pair that │
209 comprises a boundary. │
210 tcl_wordBreakBefore str start │
212 Returns the index of the first word boundary before the starting │
213 index start in the string str. Returns -1 if there are no more │
214 boundaries before the starting point in the given string. The │
215 index returned refers to the second character of the pair that │
216 comprises a boundary.
217
220 The following global variables are defined or used by the procedures in
221 the Tcl library:
222 auto_execs
224 Used by auto_execok to record information about whether particu‐
225 lar commands exist as executable files.
226 auto_index
228 Used by auto_load to save the index information read from disk.
229 auto_noexec
231 If set to any value, then unknown will not attempt to auto-exec
232 any commands.
233 auto_noload
235 If set to any value, then unknown will not attempt to auto-load
236 any commands.
237 auto_path
239 If set, then it must contain a valid Tcl list giving directories
240 to search during auto-load operations. This variable is ini‐
241 tialized during startup to contain, in order: the directories
242 listed in the TCLLIBPATH environment variable, the directory
243 named by the $tcl_library variable, the parent directory of
244 $tcl_library, the directories listed in the $tcl_pkgPath vari‐
245 able.
246 env(TCL_LIBRARY)
248 If set, then it specifies the location of the directory contain‐
249 ing library scripts (the value of this variable will be assigned
250 to the tcl_library variable and therefore returned by the com‐
251 mand info library). If this variable isn't set then a default
252 value is used.
253 env(TCLLIBPATH)
255 If set, then it must contain a valid Tcl list giving directories
256 to search during auto-load operations. Directories must be
257 specified in Tcl format, using "/" as the path separator,
258 regardless of platform. This variable is only used when ini‐
259 tializing the auto_path variable.
260 tcl_nonwordchars
262 This variable contains a regular expression that is used by rou‐ │
263 tines like tcl_endOfWord to identify whether a character is part │
264 of a word or not. If the pattern matches a character, the char‐ │
265 acter is considered to be a non-word character. On Windows │
266 platforms, spaces, tabs, and newlines are considered non-word │
267 characters. Under Unix, everything but numbers, letters and │
268 underscores are considered non-word characters. │
269 tcl_wordchars │
271 This variable contains a regular expression that is used by rou‐ │
272 tines like tcl_endOfWord to identify whether a character is part │
273 of a word or not. If the pattern matches a character, the char‐ │
274 acter is considered to be a word character. On Windows plat‐ │
275 forms, words are comprised of any character that is not a space, │
276 tab, or newline. Under Unix, words are comprised of numbers, │
277 letters or underscores.
278 unknown_pending
280 Used by unknown to record the command(s) for which it is search‐
281 ing. It is used to detect errors where unknown recurses on
282 itself infinitely. The variable is unset before unknown
283 returns.
284
287 info(n), re_syntax(n)
288
291 auto-exec, auto-load, library, unknown, word, whitespace
292Tcl 8.0 library(n)