1library(n)                   Tcl Built-In Commands                  library(n)


8       auto_execok,   auto_import,   auto_load,   auto_mkindex,  auto_qualify,
9       auto_reset,       tcl_findLibrary,        parray,        tcl_endOfWord,
10       tcl_startOfNextWord,    tcl_startOfPreviousWord,    tcl_wordBreakAfter,
11       tcl_wordBreakBefore - standard library of Tcl procedures


14       auto_execok cmd
15       auto_import pattern
16       auto_load cmd
17       auto_mkindex dir pattern pattern ...
18       auto_qualify command namespace
19       auto_reset
20       tcl_findLibrary basename version patch initScript enVarName varName
21       parray arrayName ?pattern?
22       tcl_endOfWord str start
23       tcl_startOfNextWord str start
24       tcl_startOfPreviousWord str start
25       tcl_wordBreakAfter str start
26       tcl_wordBreakBefore str start


30       Tcl includes a library of Tcl procedures for commonly-needed functions.
31       The procedures defined in the Tcl library are generic ones suitable for
32       use by many different applications.  The location of the Tcl library is
33       returned  by the info library command.  In addition to the Tcl library,
34       each application will normally have its own library of  support  proce‐
35       dures  as  well;  the location of this library is normally given by the
36       value of the $app_library global variable, where app is the name of the
37       application.   For  example,  the location of the Tk library is kept in
38       the variable tk_library.
40       To access the procedures in the  Tcl  library,  an  application  should
41       source  the file init.tcl in the library, for example with the Tcl com‐
42       mand
44              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.


53       The following procedures are provided in the Tcl library:
55       auto_execok cmd
56              Determines whether there is an executable file or shell  builtin
57              by  the  name  cmd.  If so, it returns a list of arguments to be
58              passed to exec to execute the executable file or  shell  builtin
59              named by cmd.  If not, it returns an empty string.  This command
60              examines the directories in the current search  path  (given  by
61              the  PATH  environment variable) in its search for an executable
62              file named cmd.  On Windows platforms, the  search  is  expanded
63              with  the  same directories and file extensions as used by exec.
64              Auto_execok remembers information about previous searches in  an
65              array  named  auto_execs;  this avoids the path search in future
66              calls for the same cmd.  The command auto_reset may be  used  to
67              force auto_execok to forget its cached information.
69       auto_import pattern
70              Auto_import  is  invoked  during  namespace import to see if the
71              imported commands specified by pattern reside in  an  autoloaded
72              library.   If  so,  the commands are loaded so that they will be
73              available to the interpreter for creating the import links.   If
74              the commands do not reside in an autoloaded library, auto_import
75              does nothing.  The pattern matching is  performed  according  to
76              the matching rules of namespace import.
78       auto_load cmd
79              This  command  attempts to load the definition for a Tcl command
80              named cmd.  To do this, it searches an auto-load path, which  is
81              a  list of one or more directories.  The auto-load path is given
82              by the global variable auto_path if it exists.  If there  is  no
83              auto_path  variable, then the TCLLIBPATH environment variable is
84              used, if it exists.  Otherwise the auto-load  path  consists  of
85              just  the  Tcl  library directory.  Within each directory in the
86              auto-load path there must be a file tclIndex that describes  one
87              or more commands defined in that directory and a script to eval‐
88              uate to load each of the commands.  The tclIndex file should  be
89              generated  with the auto_mkindex command.  If cmd is found in an
90              index file, then the appropriate script is evaluated  to  create
91              the  command.   The  auto_load command returns 1 if cmd was suc‐
92              cessfully created.  The command returns 0 if there was no  index
93              entry for cmd or if the script did not actually define cmd (e.g.
94              because index information is out of date).  If an  error  occurs
95              while  processing  the  script,  then  that  error  is returned.
96              Auto_load only reads the index information once and saves it  in
97              the  array  auto_index;  future calls to auto_load check for cmd
98              in the array rather than re-reading the index files.  The cached
99              index  information  may  be deleted with the command auto_reset.
100              This will force the next auto_load command to reload  the  index
101              database from disk.
103       auto_mkindex dir pattern pattern ...
104              Generates  an  index suitable for use by auto_load.  The command
105              searches dir for all files whose names match any of the  pattern
106              arguments (matching is done with the glob command), generates an
107              index of all the Tcl  command  procedures  defined  in  all  the
108              matching files, and stores the index information in a file named
109              tclIndex in dir. If no pattern is given a pattern of *.tcl  will
110              be assumed.  For example, the command
112                     auto_mkindex foo *.tcl
114              will  read all the .tcl files in subdirectory foo and generate a
115              new index file foo/tclIndex.
117              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.
124              Auto_mkindex_old  (which  has  the  same syntax as auto_mkindex)
125              parses the Tcl scripts in a relatively unsophisticated way:   if
126              any  line  contains the word “proc” as its first characters then
127              it is assumed to be a procedure definition and the next word  of
128              the  line  is  taken as the procedure's name.  Procedure defini‐
129              tions that do not appear in  this  way  (e.g. they  have  spaces
130              before  the  proc) will not be indexed.  If your script contains
131              “dangerous” code, such as global initialization code  or  proce‐
132              dure  names  with  special characters like $, *, [ or ], you are
133              safer using auto_mkindex_old.
135       auto_reset
136              Destroys  all  the  information  cached   by   auto_execok   and
137              auto_load.   This information will be re-read from disk the next
138              time it is  needed.   Auto_reset  also  deletes  any  procedures
139              listed in the auto-load index, so that fresh copies of them will
140              be loaded the next time that they are used.
142       auto_qualify command namespace
143              Computes a list of fully qualified names for command.  This list
144              mirrors  the path a standard Tcl interpreter follows for command
145              lookups:  first it looks for the command in the  current  names‐
146              pace, and then in the global namespace.  Accordingly, if command
147              is relative and namespace is not ::, the list returned  has  two
148              elements:   command scoped by namespace, as if it were a command
149              in the namespace namespace; and command as if it were a  command
150              in  the global namespace.  Otherwise, if either command is abso‐
151              lute (it begins with ::), or namespace is ::, the list  contains
152              only command as if it were a command in the global namespace.
154              Auto_qualify is used by the auto-loading facilities in Tcl, both
155              for producing auto-loading indexes such as pkgIndex.tcl, and for
156              performing the actual auto-loading of functions at runtime.
158       tcl_findLibrary basename version patch initScript enVarName varName
159              This is a standard search procedure for use by extensions during
160              their initialization.  They call  this  procedure  to  look  for
161              their  script library in several standard directories.  The last
162              component of the name of the library directory is normally base‐
163              nameversion (e.g., tk8.0), but it might be “library” when in the
164              build hierarchies.  The initScript file will be sourced into the
165              interpreter  once it is found.  The directory in which this file
166              is found is stored into the global variable  varName.   If  this
167              variable  is already defined (e.g., by C code during application
168              initialization) then no searching is done.  Otherwise the search
169              looks  in these directories: the directory named by the environ‐
170              ment variable enVarName; relative to the Tcl library  directory;
171              relative to the executable file in the standard installation bin
172              or bin/arch directory; relative to the executable  file  in  the
173              current  build tree; relative to the executable file in a paral‐
174              lel build tree.
176       parray arrayName ?pattern?
177              Prints on standard output the names and values of all  the  ele‐
178              ments  in the array arrayName, or just the names that match pat‐
179              tern (using the matching rules of string match) and their values
180              if  pattern  is given.  ArrayName must be an array accessible to
181              the caller of parray.  It may be either local or global.
183       tcl_endOfWord str start
184              Returns the index of the first end-of-word location that  occurs
185              after  a starting index start in the string str.  An end-of-word
186              location is defined to be the first non-word character following
187              the  first  word character after the starting point.  Returns -1
188              if there are no more end-of-word locations  after  the  starting
189              point.   See  the  description of tcl_wordchars and tcl_nonword‐
190              chars below for more details on how Tcl determines which charac‐
191              ters are word characters.
193       tcl_startOfNextWord str start
194              Returns  the  index  of  the  first  start-of-word location that
195              occurs after a starting index start in the string str.  A start-
196              of-word  location is defined to be the first word character fol‐
197              lowing a non-word character.  Returns -1 if there  are  no  more
198              start-of-word locations after the starting point.
200       tcl_startOfPreviousWord str start
201              Returns  the  index  of  the  first  start-of-word location that
202              occurs before a starting index start in the string str.  Returns
203              -1  if  there  are  no  more  start-of-word locations before the
204              starting point.
206       tcl_wordBreakAfter str start
207              Returns the index of the first word boundary after the  starting
208              index  start in the string str.  Returns -1 if there are no more
209              boundaries after the starting point in the  given  string.   The
210              index  returned  refers to the second character of the pair that
211              comprises a boundary.
213       tcl_wordBreakBefore str start
214              Returns the index of the first word boundary before the starting
215              index  start in the string str.  Returns -1 if there are no more
216              boundaries before the starting point in the given  string.   The
217              index  returned  refers to the second character of the pair that
218              comprises a boundary.


221       The following global variables are defined or used by the procedures in
222       the  Tcl  library.  They  fall into two broad classes, handling unknown
223       commands and packages, and determining what are words.
226       auto_execs
227              Used by auto_execok to record information about whether particu‐
228              lar commands exist as executable files.
230       auto_index
231              Used by auto_load to save the index information read from disk.
233       auto_noexec
234              If  set to any value, then unknown will not attempt to auto-exec
235              any commands.
237       auto_noload
238              If set to any value, then unknown will not attempt to  auto-load
239              any commands.
241       auto_path
242              If set, then it must contain a valid Tcl list giving directories
243              to search during auto-load  operations  (including  for  package
244              index  files  when  using  the default package unknown handler).
245              This variable is  initialized  during  startup  to  contain,  in
246              order:  the  directories  listed  in  the TCLLIBPATH environment
247              variable, the directory named by the  tcl_library  global  vari‐
248              able,  the  parent  directory  of  tcl_library,  the directories
249              listed in the tcl_pkgPath  variable.   Additional  locations  to
250              look  for  files and package indices should normally be added to
251              this variable using lappend.
253       env(TCL_LIBRARY)
254              If set, then it specifies the location of the directory contain‐
255              ing library scripts (the value of this variable will be assigned
256              to the tcl_library variable and therefore returned by  the  com‐
257              mand  info library).  If this variable is not set then a default
258              value is used.
260       env(TCLLIBPATH)
261              If set, then it must contain a valid Tcl list giving directories
262              to  search  during  auto-load  operations.   Directories must be
263              specified in Tcl  format,  using  “/”  as  the  path  separator,
264              regardless  of  platform.   This variable is only used when ini‐
265              tializing the auto_path variable.
268       These   variables    are    only    used    in    the    tcl_endOfWord,
269       tcl_startOfNextWord,  tcl_startOfPreviousWord,  tcl_wordBreakAfter, and
270       tcl_wordBreakBefore commands.
272       tcl_nonwordchars
273              This variable contains a regular expression that is used by rou‐
274              tines like tcl_endOfWord to identify whether a character is part
275              of a word or not.  If the pattern matches a character, the char‐
276              acter  is  considered  to  be  a non-word character.  On Windows
277              platforms, spaces, tabs, and newlines  are  considered  non-word
278              characters.   Under  Unix,  everything  but numbers, letters and
279              underscores are considered non-word characters.
281       tcl_wordchars
282              This variable contains a regular expression that is used by rou‐
283              tines like tcl_endOfWord to identify whether a character is part
284              of a word or not.  If the pattern matches a character, the char‐
285              acter  is  considered  to be a word character.  On Windows plat‐
286              forms, words are comprised of any character that is not a space,
287              tab,  or  newline.   Under Unix, words are comprised of numbers,
288              letters or underscores.


291       env(n), info(n), re_syntax(n)


294       auto-exec, auto-load, library, unknown, word, whitespace
298Tcl                                   8.0                           library(n)