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