'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" RCS: @(#) $Id: switch.n,v 1.5 2000/09/07 14:27:51 poenitz Exp $
-'\"
-'\" The definitions below are for supplemental macros used in Tcl/Tk
-'\" manual entries.
-'\"
-'\" .AP type name in/out ?indent?
-'\" Start paragraph describing an argument to a library procedure.
-'\" type is type of argument (int, etc.), in/out is either "in", "out",
-'\" or "in/out" to describe whether procedure reads or modifies arg,
-'\" and indent is equivalent to second arg of .IP (shouldn't ever be
-'\" needed; use .AS below instead)
-'\"
-'\" .AS ?type? ?name?
-'\" Give maximum sizes of arguments for setting tab stops. Type and
-'\" name are examples of largest possible arguments that will be passed
-'\" to .AP later. If args are omitted, default tab stops are used.
-'\"
-'\" .BS
-'\" Start box enclosure. From here until next .BE, everything will be
-'\" enclosed in one large box.
-'\"
-'\" .BE
-'\" End of box enclosure.
-'\"
-'\" .CS
-'\" Begin code excerpt.
-'\"
-'\" .CE
-'\" End code excerpt.
-'\"
-'\" .VS ?version? ?br?
-'\" Begin vertical sidebar, for use in marking newly-changed parts
-'\" of man pages. The first argument is ignored and used for recording
-'\" the version when the .VS was added, so that the sidebars can be
-'\" found and removed when they reach a certain age. If another argument
-'\" is present, then a line break is forced before starting the sidebar.
-'\"
-'\" .VE
-'\" End of vertical sidebar.
-'\"
-'\" .DS
-'\" Begin an indented unfilled display.
-'\"
-'\" .DE
-'\" End of indented unfilled display.
-'\"
-'\" .SO
-'\" Start of list of standard options for a Tk widget. The
-'\" options follow on successive lines, in four columns separated
-'\" by tabs.
-'\"
-'\" .SE
-'\" End of list of standard options for a Tk widget.
-'\"
-'\" .OP cmdName dbName dbClass
-'\" Start of description of a specific option. cmdName gives the
-'\" option's name as specified in the class command, dbName gives
-'\" the option's name in the option database, and dbClass gives
-'\" the option's class in the option database.
-'\"
-'\" .UL arg1 arg2
-'\" Print arg1 underlined, then print arg2 normally.
-'\"
-'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
-'\"
-'\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
+.TH switch n 8.5 Tcl "Tcl Built-In Commands"
+.\" The -*- nroff -*- definitions below are for supplemental macros used
+.\" in Tcl/Tk manual entries.
+.\"
+.\" .AP type name in/out ?indent?
+.\" Start paragraph describing an argument to a library procedure.
+.\" type is type of argument (int, etc.), in/out is either "in", "out",
+.\" or "in/out" to describe whether procedure reads or modifies arg,
+.\" and indent is equivalent to second arg of .IP (shouldn't ever be
+.\" needed; use .AS below instead)
+.\"
+.\" .AS ?type? ?name?
+.\" Give maximum sizes of arguments for setting tab stops. Type and
+.\" name are examples of largest possible arguments that will be passed
+.\" to .AP later. If args are omitted, default tab stops are used.
+.\"
+.\" .BS
+.\" Start box enclosure. From here until next .BE, everything will be
+.\" enclosed in one large box.
+.\"
+.\" .BE
+.\" End of box enclosure.
+.\"
+.\" .CS
+.\" Begin code excerpt.
+.\"
+.\" .CE
+.\" End code excerpt.
+.\"
+.\" .VS ?version? ?br?
+.\" Begin vertical sidebar, for use in marking newly-changed parts
+.\" of man pages. The first argument is ignored and used for recording
+.\" the version when the .VS was added, so that the sidebars can be
+.\" found and removed when they reach a certain age. If another argument
+.\" is present, then a line break is forced before starting the sidebar.
+.\"
+.\" .VE
+.\" End of vertical sidebar.
+.\"
+.\" .DS
+.\" Begin an indented unfilled display.
+.\"
+.\" .DE
+.\" End of indented unfilled display.
+.\"
+.\" .SO ?manpage?
+.\" Start of list of standard options for a Tk widget. The manpage
+.\" argument defines where to look up the standard options; if
+.\" omitted, defaults to "options". The options follow on successive
+.\" lines, in three columns separated by tabs.
+.\"
+.\" .SE
+.\" End of list of standard options for a Tk widget.
+.\"
+.\" .OP cmdName dbName dbClass
+.\" Start of description of a specific option. cmdName gives the
+.\" option's name as specified in the class command, dbName gives
+.\" the option's name in the option database, and dbClass gives
+.\" the option's class in the option database.
+.\"
+.\" .UL arg1 arg2
+.\" Print arg1 underlined, then print arg2 normally.
+.\"
+.\" .QW arg1 ?arg2?
+.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
+.\"
+.\" .PQ arg1 ?arg2?
+.\" Print an open parenthesis, arg1 in quotes, then arg2 normally
+.\" (for trailing punctuation) and then a closing parenthesis.
+.\"
+.\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
.if t .wh -1.3i ^B
.nr ^l \n(.l
.ad b
-'\" # Start an argument description
+.\" # Start an argument description
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
-\&\\$1 \\fI\\$2\\fP (\\$3)
+\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.\}
.\}
..
-'\" # define tabbing values for .AP
+.\" # define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+3n
.nr )C \\n()Bu+\\w'(in/out)'u+2n
..
.AS Tcl_Interp Tcl_CreateInterp in/out
-'\" # BS - start boxed text
-'\" # ^y = starting y location
-'\" # ^b = 1
+.\" # BS - start boxed text
+.\" # ^y = starting y location
+.\" # ^b = 1
.de BS
.br
.mk ^y
.if n \l'\\n(.lu\(ul'
.if n .fi
..
-'\" # BE - end boxed text (draw box now)
+.\" # BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.br
.nr ^b 0
..
-'\" # VS - start vertical sidebar
-'\" # ^Y = starting y location
-'\" # ^v = 1 (for troff; for nroff this doesn't matter)
+.\" # VS - start vertical sidebar
+.\" # ^Y = starting y location
+.\" # ^v = 1 (for troff; for nroff this doesn't matter)
.de VS
.if !"\\$2"" .br
.mk ^Y
.ie n 'mc \s12\(br\s0
.el .nr ^v 1u
..
-'\" # VE - end of vertical sidebar
+.\" # VE - end of vertical sidebar
.de VE
.ie n 'mc
.el \{\
.\}
.nr ^v 0
..
-'\" # Special macro to handle page bottom: finish off current
-'\" # box/sidebar if in box/sidebar mode, then invoked standard
-'\" # page bottom macro.
+.\" # Special macro to handle page bottom: finish off current
+.\" # box/sidebar if in box/sidebar mode, then invoked standard
+.\" # page bottom macro.
.de ^B
.ev 2
'ti 0
.mk ^Y
.\}
..
-'\" # DS - begin display
+.\" # DS - begin display
.de DS
.RS
.nf
.sp
..
-'\" # DE - end display
+.\" # DE - end display
.de DE
.fi
.RE
.sp
..
-'\" # SO - start of list of standard options
+.\" # SO - start of list of standard options
.de SO
+'ie '\\$1'' .ds So \\fBoptions\\fR
+'el .ds So \\fB\\$1\\fR
.SH "STANDARD OPTIONS"
.LP
.nf
.ta 5.5c 11c
.ft B
..
-'\" # SE - end of list of standard options
+.\" # SE - end of list of standard options
.de SE
.fi
.ft R
.LP
-See the \\fBoptions\\fR manual entry for details on the standard options.
+See the \\*(So manual entry for details on the standard options.
..
-'\" # OP - start of full description for a single option
+.\" # OP - start of full description for a single option
.de OP
.LP
.nf
.fi
.IP
..
-'\" # CS - begin code excerpt
+.\" # CS - begin code excerpt
.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
-'\" # CE - end code excerpt
+.\" # CE - end code excerpt
.de CE
.fi
.RE
..
+.\" # UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
-.TH switch n 7.0 Tcl "Tcl Built-In Commands"
+.\" # QW - apply quotation marks to word
+.de QW
+.ie '\\*(lq'"' ``\\$1''\\$2
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\$2
+..
+.\" # PQ - apply parens and quotation marks to word
+.de PQ
+.ie '\\*(lq'"' (``\\$1''\\$2)\\$3
+.\"" fix emacs highlighting
+.el (\\*(lq\\$1\\*(rq\\$2)\\$3
+..
+.\" # QR - quoted range
+.de QR
+.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
+..
+.\" # MT - "empty" string
+.de MT
+.QW ""
+..
.BS
'\" Note: do not modify the .SH NAME line immediately below!
.SH NAME
.sp
\fBswitch \fR?\fIoptions\fR?\fI string \fR{\fIpattern body \fR?\fIpattern body \fR...?}
.BE
-
.SH DESCRIPTION
.PP
The \fBswitch\fR command matches its \fIstring\fR argument against each of
command returns an empty string.
.PP
If the initial arguments to \fBswitch\fR start with \fB\-\fR then
-they are treated as options. The following options are
-currently supported:
+they are treated as options
+unless there are exactly two arguments to \fBswitch\fR (in which case the
+first must the \fIstring\fR and the second must be the
+\fIpattern\fR/\fIbody\fR list).
+The following options are currently supported:
.TP 10
\fB\-exact\fR
+.
Use exact matching when comparing \fIstring\fR to a pattern. This
is the default.
.TP 10
\fB\-glob\fR
+.
When matching \fIstring\fR to the patterns, use glob-style matching
(i.e. the same as implemented by the \fBstring match\fR command).
.TP 10
\fB\-regexp\fR
+.
When matching \fIstring\fR to the patterns, use regular
expression matching
(as described in the \fBre_syntax\fR reference page).
.TP 10
+\fB\-nocase\fR
+.
+Causes comparisons to be handled in a case-insensitive manner.
+.TP 10
+\fB\-matchvar\fR \fIvarName\fR
+.
+This option (only legal when \fB\-regexp\fR is also specified)
+specifies the name of a variable into which the list of matches
+found by the regular expression engine will be written. The first
+element of the list written will be the overall substring of the input
+string (i.e. the \fIstring\fR argument to \fBswitch\fR) matched, the
+second element of the list will be the substring matched by the first
+capturing parenthesis in the regular expression that matched, and so
+on. When a \fBdefault\fR branch is taken, the variable will have the
+empty list written to it. This option may be specified at the same
+time as the \fB\-indexvar\fR option.
+.TP 10
+\fB\-indexvar\fR \fIvarName\fR
+.
+This option (only legal when \fB\-regexp\fR is also specified)
+specifies the name of a variable into which the list of indices
+referring to matching substrings
+found by the regular expression engine will be written. The first
+element of the list written will be a two-element list specifying the
+index of the start and index of the first character after the end of
+the overall substring of the input
+string (i.e. the \fIstring\fR argument to \fBswitch\fR) matched, in a
+similar way to the \fB\-indices\fR option to the \fBregexp\fR can
+obtain. Similarly, the second element of the list refers to the first
+capturing parenthesis in the regular expression that matched, and so
+on. When a \fBdefault\fR branch is taken, the variable will have the
+empty list written to it. This option may be specified at the same
+time as the \fB\-matchvar\fR option.
+.TP 10
\fB\-\|\-\fR
+.
Marks the end of options. The argument following this one will
be treated as \fIstring\fR even if it starts with a \fB\-\fR.
+This is not required when the matching patterns and bodies are grouped
+together in a single argument.
.PP
Two syntaxes are provided for the \fIpattern\fR and \fIbody\fR arguments.
The first uses a separate argument for each of the patterns and commands;
the behavior of the second form different than the first form in some
cases.
.PP
-If a \fIbody\fR is specified as ``\fB\-\fR'' it means that the \fIbody\fR
+If a \fIbody\fR is specified as
+.QW \fB\-\fR
+it means that the \fIbody\fR
for the next pattern should also be used as the body for this
-pattern (if the next pattern also has a body of ``\fB\-\fR''
+pattern (if the next pattern also has a body of
+.QW \fB\-\fR
then the body after that is used, and so on).
This feature makes it possible to share a single \fIbody\fR among
several patterns.
Beware of how you place comments in \fBswitch\fR commands. Comments
should only be placed \fBinside\fR the execution body of one of the
patterns, and not intermingled with the patterns.
+.SH "EXAMPLES"
+.PP
+The \fBswitch\fR command can match against variables and not just
+literals, as shown here (the result is \fI2\fR):
+.PP
+.CS
+set foo "abc"
+\fBswitch\fR abc a \- b {expr {1}} $foo {expr {2}} default {expr {3}}
+.CE
+.PP
+Using glob matching and the fall-through body is an alternative to
+writing regular expressions with alternations, as can be seen here
+(this returns \fI1\fR):
.PP
-Below are some examples of \fBswitch\fR commands:
.CS
-\fBswitch\0abc\0a\0\-\0b\0{format 1}\0abc\0{format 2}\0default\0{format 3}\fR
+\fBswitch\fR \-glob aaab {
+ a*b \-
+ b {expr {1}}
+ a* {expr {2}}
+ default {expr {3}}
+}
.CE
-will return \fB2\fR,
+.PP
+Whenever nothing matches, the \fBdefault\fR clause (which must be
+last) is taken. This example has a result of \fI3\fR:
+.PP
.CS
-\fBswitch\0\-regexp\0aaab {
- ^a.*b$\0\-
- b\0{format 1}
- a*\0{format 2}
- default\0{format 3}
-}\fR
+\fBswitch\fR xyz {
+ a \-
+ b {
+ # Correct Comment Placement
+ expr {1}
+ }
+ c {
+ expr {2}
+ }
+ default {
+ expr {3}
+ }
+}
.CE
-will return \fB1\fR, and
+.PP
+When matching against regular expressions, information about what
+exactly matched is easily obtained using the \fB\-matchvar\fR option:
+.PP
.CS
-\fBswitch\0xyz {
- a
- \-
- b
- {
- # Correct Comment Placement
- format 1
- }
- a*
- {format 2}
- default
- {format 3}
-}\fR
+\fBswitch\fR \-regexp \-matchvar foo \-\- $bar {
+ a(b*)c {
+ puts "Found [string length [lindex $foo 1]] 'b's"
+ }
+ d(e*)f(g*)h {
+ puts "Found [string length [lindex $foo 1]] 'e's and\e
+ [string length [lindex $foo 2]] 'g's"
+ }
+}
.CE
-will return \fB3\fR.
-
.SH "SEE ALSO"
for(n), if(n), regexp(n)
-
.SH KEYWORDS
switch, match, regular expression
+.\" Local Variables:
+.\" mode: nroff
+.\" End:
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