/************************************************************************
 *  right-shift-block.ced
 *
 *  This ARexx program for CygnusEd Pro moves the selected block right
 *  one tab position. This script uses a very simplistic approach, simply
 *  inserting a tab character at the beginning of each line in the block.
 *  CED will automatically substitute spaces for the tab, if you have
that
 *  feature enabled.
 *
 *  Author:     Mark R. Rinfret, August 1990
 *

************************************************************************/

/* Allow CygnusEd to pass status variables */
options results

/* Tell ARexx to talk to CygnusEd */
address 'rexx_ced'

cr = '0A'x
tab = '09'x

/* Is a block marked? */

status 69

if result = -1 then do
    okay1 "No block marked for right-shift-block!"
    exit
end

beginLine = result + 1
saveBegin = beginLine

/* Get current line number. */

status 57
endLine = result + 1

if endLine < beginLine then do
    temp = endLine
    endLine = beginLine
    beginLine = temp
end

do while beginLine <= endLine
    jumpto beginLine 0
        status 55
        /* Remove the newline at the end of the result. */
        theLine = substr(result,1,length(result)-1);
        delete to eol
        /* Push the text over with a tab. If tab-to-spaces conversion is
enabled,
     * this still works fine.
     */
    text tab || theLine
    beginLine = beginLine + 1
end

exit



/* LeftShiftLine - shift a line left one tab position.
 * Global variables used:
 *      firstTab    - first tab stop position
 *      oldLine     - string containing original line
 *      newLine     - string to receive result
 */
      
LeftShiftLine: procedure expose firstTab oldLine newLine

    /* Watch out for zero-length strings. */

    oldLineLength = length(oldLine)
    if  oldLineLength = 0 then do
        newLine = ""
        return 0
    end

    /* Search for first non-blank character or tab stop. */

    blanks = 0
    spacePos = 1
    do spacePos = 1 to oldLineLength
        if spacePos > firstTab | substr(oldLine,spacePos,1) ~= " " then
do
            blanks = spacePos - 1
            leave spacePos
        end
    end

    /* If the original line has embedded tabs, get cheap 'n dirty. Just 
     * delete the first tab we see. Actually, to do this with precision,
     * we should find the last tab that occurs before the first non-white
     * character and delete it. That approach would support variable tab
     * settings more accurately. An exercise for the reader... :-)
     */

    tabFound = pos('09'X, oldLine)

    if tabFound > 0 & (tabFound < blanks  | tabFound = 1) then do
        newLine = delstr(oldLine,tabFound,1)
        return 0
    end

    /* There's a (remote) possibility that we've found a line of blanks.
*/

    if blanks > 0 then do
        newLine = delstr(oldLine, 1, blanks)
        end
    else do
        newLine = oldLine
        end
    return 0