'\"
'\" Copyright (c) 2008 Peter Spjuth <pspjuth@users.sourceforge.net>
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH prefix 3tcl 8.6 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?
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.\"	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)
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.\"	of man pages.  The first argument is ignored and used for recording
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.\"	found and removed when they reach a certain age.  If another argument
.\"	is present, then a line break is forced before starting the sidebar.
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.\"
.\" .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
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.   ie !"\\$2"" .TP \\n()Cu
.   el          .TP 15
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.br
.ie !"\\$2"" \{\
\&\\$1	\\fI\\$2\\fP
.\}
.el \{\
\&\\fI\\$1\\fP
.\}
.\}
..
.\"	# define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+3n
.nr )B \\n()Au+15n
.\"
.if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+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
.de BS
.br
.mk ^y
.nr ^b 1u
.if n .nf
.if n .ti 0
.if n \l'\\n(.lu\(ul'
.if n .fi
..
.\"	# BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.mk ^t
.ie n \l'\\n(^lu\(ul'
.el \{\
.\"	Draw four-sided box normally, but don't draw top of
.\"	box if the box started on an earlier page.
.ie !\\n(^b-1 \{\
\h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
.\}
.el \}\
\h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
.\}
.\}
.fi
.br
.nr ^b 0
..
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.\"	# ^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
..
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.de VE
.ie n 'mc
.el \{\
.ev 2
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.mk ^t
\h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n'
.sp -1
.fi
.ev
.\}
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..
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.\"	# box/sidebar if in box/sidebar mode, then invoked standard
.\"	# page bottom macro.
.de ^B
.ev 2
'ti 0
'nf
.mk ^t
.if \\n(^b \{\
.\"	Draw three-sided box if this is the box's first page,
.\"	draw two sides but no top otherwise.
.ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
.el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
.\}
.if \\n(^v \{\
.nr ^x \\n(^tu+1v-\\n(^Yu
\kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c
.\}
.bp
'fi
.ev
.if \\n(^b \{\
.mk ^y
.nr ^b 2
.\}
.if \\n(^v \{\
.mk ^Y
.\}
..
.\"	# DS - begin display
.de DS
.RS
.nf
.sp
..
.\"	# DE - end display
.de DE
.fi
.RE
.sp
..
.\"	# 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
.de SE
.fi
.ft R
.LP
See the \\*(So manual entry for details on the standard options.
..
.\"	# OP - start of full description for a single option
.de OP
.LP
.nf
.ta 4c
Command-Line Name:	\\fB\\$1\\fR
Database Name:	\\fB\\$2\\fR
Database Class:	\\fB\\$3\\fR
.fi
.IP
..
.\"	# CS - begin code excerpt
.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
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.de CE
.fi
.RE
..
.\"	# UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
.\"	# 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
tcl::prefix \- facilities for prefix matching
.SH SYNOPSIS
.nf
\fB::tcl::prefix all\fR \fItable string\fR
\fB::tcl::prefix longest\fR \fItable string\fR
\fB::tcl::prefix match\fR ?\fIoption ...\fR? \fItable string\fR
.fi
.BE
.SH DESCRIPTION
.PP
This document describes commands looking up a prefix in a list of strings.
The following commands are supported:
.TP
\fB::tcl::prefix all\fR \fItable string\fR
.
Returns a list of all elements in \fItable\fR that begin with the prefix
\fIstring\fR.
.TP
\fB::tcl::prefix longest\fR \fItable string\fR
.
Returns the longest common prefix of all elements in \fItable\fR that
begin with the prefix \fIstring\fR.
.TP
\fB::tcl::prefix match\fR ?\fIoptions\fR? \fItable string\fR
.
If \fIstring\fR equals one element in \fItable\fR or is a prefix to exactly
one element, the matched element is returned. If not, the result depends
on the \fB\-error\fR option. (It is recommended that the \fItable\fR be sorted
before use with this subcommand, so that the list of matches presented in the
error message also becomes sorted, though this is not strictly necessary for
the operation of this subcommand itself.)
.RS
.TP
\fB\-exact\fR\0
.
Accept only exact matches.
.TP
\fB\-message\0\fIstring\fR
.
Use \fIstring\fR in the error message at a mismatch. Default is
.QW option .
.TP
\fB\-error\0\fIoptions\fR
.
The \fIoptions\fR are used when no match is found. If \fIoptions\fR is empty,
no error is generated and an empty string is returned. Otherwise the
\fIoptions\fR are used as \fBreturn\fR options when generating the error
message. The default corresponds to setting
.QW "\-level 0" .
Example: If
.QW "\fB\-error\fR {\-errorcode MyError \-level 1}"
is used, an error would be generated as:
.RS
.PP
.CS
return \-errorcode MyError \-level 1 \-code error \e
       "ambiguous option ..."
.CE
.RE
.RE
.SH "EXAMPLES"
.PP
Basic use:
.PP
.CS
namespace import ::tcl::prefix
\fBprefix match\fR {apa bepa cepa} apa
     \fI\(-> apa\fR
\fBprefix match\fR {apa bepa cepa} a
     \fI\(-> apa\fR
\fBprefix match\fR \-exact {apa bepa cepa} a
     \fI\(-> bad option "a": must be apa, bepa, or cepa\fR
\fBprefix match\fR \-message "switch" {apa ada bepa cepa} a
     \fI\(-> ambiguous switch "a": must be apa, ada, bepa, or cepa\fR
\fBprefix longest\fR {fblocked fconfigure fcopy file fileevent flush} fc
     \fI\(-> fco\fR
\fBprefix all\fR {fblocked fconfigure fcopy file fileevent flush} fc
     \fI\(-> fconfigure fcopy\fR
.CE
.PP
Simplifying option matching:
.PP
.CS
array set opts {\-apa 1 \-bepa "" \-cepa 0}
foreach {arg val} $args {
    set opts([\fBprefix match\fR {\-apa \-bepa \-cepa} $arg]) $val
}
.CE
.PP
Creating a \fBswitch\fR that supports prefixes:
.PP
.CS
switch [\fBprefix match\fR {apa bepa cepa} $arg] {
    apa  { }
    bepa { }
    cepa { }
}
.CE
.SH "SEE ALSO"
lsearch(3tcl), namespace(3tcl), string(3tcl), Tcl_GetIndexFromObj(3tcl)
.SH "KEYWORDS"
prefix, table lookup
'\" Local Variables:
'\" mode: nroff
'\" End: