Basic Editor for 300 LOC or so?

[Ed Davis]

Anyone got anything close to bare bones editor only a few c's of lines ?

How about this?  Based on an old FreeBasic editor I found a while back.  It used linked lists, had a few issues.
I converted it to QB64, used an array of strings instead of the linked list, fixed a few bugs, probably added a few more.  Available commands are in the main sub below.  
Very bare bones! But less than 200 lines, and pretty easy to follow
Does not currently handle horizontal scrolling.

Code: (Select All)

option _explicit



declare function down&

declare function up&

declare function pgdn&

declare function pgup&

declare function cmleft&

declare function cmright&



const c_nlines = 5000, true = -1, false = 0

redim shared linelist(1 to c_nlines) as string



dim shared as long curline, numlines, cx, cy, sy, rows, cols, junk

numlines = 0: cx = 0: cy = 0: sy = 0



rows = _height: cols = _width

rows = rows - 1      ' allow one for a status line



loadfile command$

locate , , 0

main

locate rows + 1, 1, 1

end



sub main

    dim thekey as string

    dim refresh as integer



    redraw

    do

        refresh = true

        thekey = inkey$



        select case thekey

            case chr$(0)+"P":          junk = down

            case chr$(0)+"H":          junk = up

            case chr$(0)+"M":          junk = cmright

            case chr$(0)+"K":          junk = cmleft

            case chr$(0)+"Q":          junk = pgdn

            case chr$(0)+"I":          junk = pgup

            case chr$(0)+"G":          cx = 0                      'home

            case chr$(0)+"O":          cx = len(linelist(curline)) 'end

            case chr$(0)+chr$(118):    while pgdn: wend      'ctrl-pgdn

            case chr$(0)+chr$(132):    while pgup: wend      'ctrl-pgup

            case chr$(13):              enter

            case chr$(8):              backspace

            case chr$(0)+"S":          cdelete

            case chr$(32) to chr$(128): selfinsert thekey

            case else: refresh = false

        end select

        if refresh then redraw

    loop until thekey = chr$(27)

end sub



sub loadfile(f as string)

    linelist(1) = ""

    curline = 1

    if not _fileexists(f) then numlines = 1: exit sub

    open f for input as #1

    do

        numlines = numlines + 1

        if numlines > ubound(linelist) then redim _preserve linelist(ubound(linelist) + c_nlines)

        line input #1, linelist(numlines)

    loop until eof(1)

    close

end sub



function down&

    if curline >= numlines then down = false: exit function

    if cy = rows - 1 then sy = sy + 1 else cy = cy + 1

    curline = curline + 1

    if len(linelist(curline)) < cx then cx = len(linelist(curline))

    down = true

end function



function up&

    if curline <= 1 then up = false: exit function

    if cy = 0 then sy = sy - 1 else cy = cy - 1

    curline = curline - 1

    if len(linelist(curline)) < cx then cx = len(linelist(curline))

    up = true

end function



function cmleft&

    if cx = 0 then

        if curline <= 1 then cmleft = false: exit function

        junk = up: cx = len(linelist(curline))

    else

        cx = cx - 1

    end if

    cmleft = true

end function



function cmright&

    if cx = len(linelist(curline)) then

        if curline >= numlines then cmright = false: exit function

        junk = down: cx = 0

    else

        cx = cx + 1

    end if

    cmright = true

end function



function pgdn&

    dim i as long

    if curline >= numlines then pgdn = false: exit function

    for i = 1 to rows - 1

        if not down then exit for

    next

    pgdn = true

end function



function pgup&

    dim i as long

    if curline <= 1 then pgup = false: exit function

    for i = 1 to rows - 1

        if not up then exit for

    next

    pgup = true

end function



sub enter

    dim as long n

    dim as string s



    numlines = numlines + 1

    if numlines > ubound(linelist) then redim _preserve linelist(ubound(linelist) + c_nlines)

    s = mid$(linelist(curline), cx + 1)

    linelist(curline) = left$(linelist(curline), cx)

    ' move everything after curline down one

    for n = numlines to curline + 1 step -1

        linelist(n) = linelist(n - 1)

    next n

    curline = curline + 1

    linelist(curline) = s

    if cy = rows - 1 then sy = sy + 1 else cy = cy + 1

    cx = 0

end sub



sub backspace

    dim as long line_len, n

    if cx = 0 then

        if curline <= 1 then exit sub

        line_len = len(linelist(curline - 1))

        linelist(curline - 1) = linelist(curline - 1) + linelist(curline)

        ' move everything after curline up one

        for n = curline to numlines - 1

            linelist(n) = linelist(n + 1)

        next n

        numlines = numlines - 1

        cx = line_len

        if cy = 0 then sy = sy - 1 else cy = cy - 1

        curline = curline - 1

    else

        linelist(curline) = left$(linelist(curline), cx - 1) + mid$(linelist(curline), cx + 1)

        cx = cx - 1

    end if

end sub



sub cdelete

    if cx = len(linelist(curline)) then if curline >= numlines then exit sub

    junk = cmright

    backspace

end sub



sub selfinsert(thekey as string)

    linelist(curline) = left$(linelist(curline), cx) + thekey + mid$(linelist(curline), cx + 1)

    cx = cx + 1

end sub



sub redraw

    dim as long y, n



    cls

    n = curline - cy

    if n < 1 then n = 1



    for y = 1 to rows

        locate y, 1

        ? left$(linelist(n), cols);

        if n = numlines then exit for

        n = n + 1

    next



    locate cy + 1, cx + 1

    color 0, 7

    ? chr$(screen(cy + 1, cx + 1));



    locate rows + 1, 1

    ? "Line: "; cy + sy + 1; " of "; numlines; " Col: "; cx + 1;



    color 7, 0

end sub