trim.tcl

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/*  trim.tcl --*/
/* */
/*  Various ways of trimming a string.*/
/* */
/*  Copyright (c) 2000      by Ajuba Solutions.*/
/*  Copyright (c) 2000      by Eric Melski <ericm@ajubasolutions.com>*/
/*  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: trim.tcl,v 1.5 2006/04/21 04:42:28 andreas_kupries Exp $*/

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

package require Tcl 8.2

namespace ::textutil::trim {}

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

ret  ::textutil::trim::trimleft (type text , optional trim ="[ \t]+") {
    regsub -line -all -- [MakeStr $trim left] $text {} text
    return $text
}

ret  ::textutil::trim::trimright (type text , optional trim ="[ \t]+") {
    regsub -line -all -- [MakeStr $trim right] $text {} text
    return $text
}

ret  ::textutil::trim::trim (type text , optional trim ="[ \t]+") {
    regsub -line -all -- [MakeStr $trim left]  $text {} text
    regsub -line -all -- [MakeStr $trim right] $text {} text
    return $text
}



/*  @c Strips <a prefix> from <a text>, if found at its start.*/
/* */
/*  @a text: The string to check for <a prefix>.*/
/*  @a prefix: The string to remove from <a text>.*/
/* */
/*  @r The <a text>, but without <a prefix>.*/
/* */
/*  @i remove, prefix*/

ret  ::textutil::trim::trimPrefix (type text , type prefix) {
    if {[string first $prefix $text] == 0} {
    return [string range $text [string length $prefix] end]
    } else {
    return $text
    }
}


/*  @c Removes the Heading Empty Lines of <a text>.*/
/* */
/*  @a text: The text block to manipulate.*/
/* */
/*  @r The <a text>, but without heading empty lines.*/
/* */
/*  @i remove, empty lines*/

ret  ::textutil::trim::trimEmptyHeading (type text) {
    regsub -- "^(\[ \t\]*\n)*" $text {} text
    return $text
}

/*  ### ### ### ######### ######### #########*/
/*  Helper commands. Internal*/

ret  ::textutil::trim::MakeStr ( type string , type pos )  {
    variable StrU
    variable StrR
    variable StrL

    if { "$string" != "$StrU" } {
        set StrU $string
        set StrR "(${StrU})\$"
        set StrL "^(${StrU})"
    }
    if { "$pos" == "left" } {
        return $StrL
    }
    if { "$pos" == "right" } {
        return $StrR
    }

    return -code error "Panic, illegal position key \"$pos\""
}

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

namespace ::textutil::trim {        
    variable StrU "\[ \t\]+"
    variable StrR "(${StrU})\$"
    variable StrL "^(${StrU})"

    namespace export \
        trim trimright trimleft \
        trimPrefix trimEmptyHeading
}

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

package provide textutil::trim 0.7