string.tcl

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/*  string.tcl --*/
/* */
/*  Utilities for manipulating strings, words, single lines,*/
/*  paragraphs, ...*/
/* */
/*  Copyright (c) 2000      by Ajuba Solutions.*/
/*  Copyright (c) 2000      by Eric Melski <ericm@ajubasolutions.com>*/
/*  Copyright (c) 2002      by Joe English <jenglish@users.sourceforge.net>*/
/*  Copyright (c) 2001-2006 by Andreas Kupries <andreas_kupries@users.sourceforge.net>*/
/* */
/*  See the file "license.terms" for information on usage and redistribution*/
/*  of this file, and for a DISCLAIMER OF ALL WARRANTIES.*/
/*  */
/*  RCS: @(#) $Id: string.tcl,v 1.1 2006/04/21 04:42:28 andreas_kupries Exp $*/

/*  ### ### ### ######### ######### #########*/
/*  Requirements*/

package require Tcl 8.2

namespace ::textutil::string {}

/*  ### ### ### ######### ######### #########*/
/*  API implementation*/

/*  @c Removes the last character from the given <a string>.*/
/* */
/*  @a string: The string to manipulate.*/
/* */
/*  @r The <a string> without its last character.*/
/* */
/*  @i chopping*/

ret  ::textutil::string::chop (type string) {
    return [string range $string 0 [expr {[string length $string]-2}]]
}

/*  @c Removes the first character from the given <a string>.*/
/*  @c Convenience procedure.*/
/* */
/*  @a string: string to manipulate.*/
/* */
/*  @r The <a string> without its first character.*/
/* */
/*  @i tail*/

ret  ::textutil::string::tail (type string) {
    return [string range $string 1 end]
}

/*  @c Capitalizes first character of the given <a string>.*/
/*  @c Complementary procedure to <p ::textutil::uncap>.*/
/* */
/*  @a string: string to manipulate.*/
/* */
/*  @r The <a string> with its first character capitalized.*/
/* */
/*  @i capitalize*/

ret  ::textutil::string::cap (type string) {
    return [string toupper [string index $string 0]][string range $string 1 end]
}

/*  @c unCapitalizes first character of the given <a string>.*/
/*  @c Complementary procedure to <p ::textutil::cap>.*/
/* */
/*  @a string: string to manipulate.*/
/* */
/*  @r The <a string> with its first character uncapitalized.*/
/* */
/*  @i uncapitalize*/

ret  ::textutil::string::uncap (type string) {
    return [string tolower [string index $string 0]][string range $string 1 end]
}

/*  Compute the longest string which is common to all strings given to*/
/*  the command, and at the beginning of said strings, i.e. a prefix. If*/
/*  only one argument is specified it is treated as a list of the*/
/*  strings to look at. If more than one argument is specified these*/
/*  arguments are the strings to be looked at. If only one string is*/
/*  given, in either form, the string is returned, as it is its own*/
/*  longest common prefix.*/

ret  ::textutil::string::longestCommonPrefix (type args) {
    return [longestCommonPrefixList $args]
}

ret  ::textutil::string::longestCommonPrefixList (type list) {
    if {[llength $list] == 0} {
    return ""
    } elseif {[llength $list] == 1} {
    return [lindex $list 0]
    }

    set list [lsort  $list]
    set min  [lindex $list 0]
    set max  [lindex $list end]

    # Min and max are the two strings which are most different. If
    # they have a common prefix, it will also be the common prefix for
    # all of them.

    # Fast bailouts for common cases.

    set n [string length $min]
    if {$n == 0}                         {return ""}
    if {0 == [string compare $min $max]} {return $min}

    set prefix ""
    for {set i 0} {$i < $n} {incr i} {
    if {0 == [string compare [set x [string range $min 0 $i]] [string range $max 0 $i]]} {
        set prefix $x
        continue
    }
    break
    }
    return $prefix
}

/*  ### ### ### ######### ######### #########*/
/*  Data structures*/

namespace ::textutil::string {
    /*  Export the imported commands*/

    namespace export chop tail cap uncap
    namespace export longestCommonPrefix
    namespace export longestCommonPrefixList
}

/*  ### ### ### ######### ######### #########*/
/*  Ready*/

package provide textutil::string 0.7