JCSM Shareware Collection 1996 September/JCSM Shareware Collection (JCS Distribution) (September 1996).ISO/prgtools/euphor13.zip/ED.EX

Text File | 1995-05-13 | 47KB | 1,862 lines

    ----------------------------------------------------------
    --       This Euphoria Editor was developed by          --
    --            Rapid Deployment Software.                --
    --                                                      --
    -- Permission is freely granted to anyone to modify     --
    -- and/or redistribute this editor (ed.ex, syncolor.e). --
    -- You may even sell it as it is, or with your          --
    -- modifications.                                       --
    ----------------------------------------------------------

without type_check -- makes it a bit faster

include graphics.e
include get.e
include file.e

constant TRUE = 1,
     FALSE = 0

-------- user-modifiable parameters:

constant PROG_INDENT = 4  -- tab width for editing program source files
              -- (tab width is 8 for other files)
constant E_FILES = {".e", ".ex", ".pro"}             -- Euphoria files
constant PROG_FILES = E_FILES & {".c", ".h", ".bas"} -- program indent files

constant WANT_COLOR_SYNTAX  = TRUE -- FALSE if you don't want
                   -- color syntax highlighting

constant WANT_AUTO_COMPLETE = TRUE -- FALSE if you don't want
                   -- auto-completion of Euphoria statements

constant HOT_KEYS = TRUE  -- FALSE if you want to hit Enter after each
              -- command like you did with v1.2

-- cursor style:
constant ED_CURSOR = UNDERLINE_CURSOR
          -- BLOCK_CURSOR
          -- HALF_BLOCK_CURSOR

-- number of lines on screen: (25,28,43,50)
constant INITIAL_LINES = 25,  -- when editor starts up
     FINAL_LINES = 25     -- when editor is finished

-- colors
constant TOP_LINE_TEXT_COLOR = BLACK,
     TOP_LINE_BACK_COLOR = BROWN,
     TOP_LINE_DIM_COLOR = GRAY,
     BACKGROUND_COLOR = WHITE

-- colors needed by syncolor.e:
-- Adjust to suit your monitor and your taste.
global constant NORMAL_COLOR = GRAY,   -- BLACK might look better
        COMMENT_COLOR = RED,
        KEYWORD_COLOR = BLUE,
        BUILTIN_COLOR = MAGENTA,
        STRING_COLOR = BROWN,  -- GREEN might look better
        BRACKET_COLOR = {NORMAL_COLOR, BLACK, YELLOW, GREEN,
                 BRIGHT_WHITE, CYAN, BRIGHT_BLUE}

constant CONTROL_CHAR = 254 -- change funny control chars to this

-------- end of user-modifiable parameters


-- output device:
global constant SCREEN = 1

constant SCREEN_WIDTH = 80

global constant BLANK_LINE = repeat(' ', SCREEN_WIDTH)

-- special input characters
constant ESCAPE = 27,
     CR = 13,
     BS = 8,
     HOME = 327,
     PAGE_UP = 329,
     END = 335,
     PAGE_DOWN = 337,
     INSERT = 338,
     DELETE = 339,
     ARROW_LEFT = 331,
     ARROW_RIGHT = 333,
     ARROW_UP = 328,
     ARROW_DOWN = 336,
     F1 = 315,
     F10 = 324,
     CONTROL_DELETE = 403, -- key for line-delete
                   -- (not available on some systems)
     CONTROL_D      = 4    -- alternate key for line-delete

constant CONTROL_CHARS = {ESCAPE, BS, DELETE, PAGE_UP, PAGE_DOWN,
              INSERT, CONTROL_DELETE, CONTROL_D,
              ARROW_LEFT, ARROW_RIGHT, ARROW_UP, ARROW_DOWN,
              HOME, END, F1, F1+1, F1+2, F1+3, F1+4, F1+5,
              F1+6, F1+7, F1+8, F10}

constant STANDARD_TAB_WIDTH = 8

constant MAX_WINDOWS = 10 -- F1..F10

type boolean(integer x)
    return x = TRUE or x = FALSE
end type

type natural(integer x)
    return x >= 0
end type

type positive_int(integer x)
    return x >= 1
end type

sequence buffer -- In-memory buffer where the file is manipulated.
-- This is a sequence where each element is a sequence
-- containing one line of text. Each line of text ends with '\n'

positive_int screen_length  -- number of lines on physical screen

positive_int window_base    -- location of first line of current window
                -- (status line)
window_base = 1
positive_int window_length  -- number of lines of text in current window

sequence window_list -- state info for all windows
window_list = {0}

sequence buffer_list -- all buffers
buffer_list = {}

type window_id(integer x)
    return x >= 1 and x <= length(window_list)
end type

type buffer_id(integer x)
    return x >= 0 and x <= length(buffer_list)
end type

type window_line(integer x)
-- a valid line in the current window
    return x >= 1 and x <= window_length
end type

type screen_col(integer x)
-- a valid column on the screen
    return x >= 1 and x <= SCREEN_WIDTH
end type

type buffer_line(integer x)
-- a valid buffer line
    return (x >= 1 and x <= length(buffer)) or x = 1
end type

type char(integer x)
-- a character
    return x >= 0 and x <= 511
end type

type extended_char(integer x)
    return char(x) or x = -1
end type

type file_number(integer x)
    return x >= -1
end type

sequence file_name   -- name of the file that we are editing

-- These are the critical state variables that all editing operations
-- must update:
buffer_line  b_line  -- current line in buffer
positive_int b_col   -- current character within line in buffer
window_line  s_line  -- line on screen corresponding to b_line
screen_col   s_col   -- column on screen corresponding to b_col

boolean stop         -- indicates when to stop processing current buffer

sequence kill_buffer -- kill buffer of deleted lines or characters
kill_buffer = {}

boolean adding_to_kill -- TRUE if still accumulating deleted lines/chars

boolean multi_color   -- use colors for keywords etc.
boolean auto_complete -- perform auto completion of statements
boolean dot_e         -- TRUE if this is a .e/.ex file
boolean modified      -- TRUE if file has been modified

atom buffer_version,    -- version of buffer contents
     my_buffer_version  -- last version used by current window
boolean control_chars    -- binary file - view but don't save

natural start_line, start_col

sequence error_message

sequence config -- video configuration

window_id window_number -- current active window
window_number = 1

buffer_id buffer_number -- current active buffer
buffer_number = 0

procedure delay(atom n)
-- an n second pause while a message is on the screen
    atom t

    t = time()
    while time() < t + n do
    end while
end procedure

procedure set_modified()
-- buffer differs from file
    modified = TRUE
    cursor(NO_CURSOR) -- hide cursor while we update the screen
    buffer_version = buffer_version + 1
end procedure

procedure clear_modified()
-- buffer is now same as file
    modified = FALSE
end procedure

function key_gets(sequence hot_keys)
-- return input string from keyboard
-- a bit more user-friendly than gets(0)
   sequence input_string
   integer line, init_column, column, char
   sequence cursor

   if not HOT_KEYS then
    hot_keys = ""
   end if
   cursor = get_position()
   line = cursor[1]
   init_column = cursor[2]
   column = init_column
   input_string = ""
   while TRUE do
    char = wait_key()

    if char = CR then
        exit

    elsif char = BS or char = ARROW_LEFT then
        if column > init_column then
        column = column - 1
        position(line, column)
        puts(SCREEN, ' ')
        position(line, column)
        input_string = input_string[1..length(input_string)-1]
        end if

    elsif char >= 32 and char <= 127 or char = '\t' then
        if column < SCREEN_WIDTH then
        if char = '\t' then
            puts(SCREEN, ' ')
        else
            puts(SCREEN, char)
        end if
        column = column + 1
        if column - init_column > length(input_string) then
            input_string = append(input_string, char)
            if column = init_column + 1 and find(char, hot_keys) then
            exit
            end if
        else
            input_string[column - init_column] = char
        end if
        end if
    end if
    end while
    return input_string
end function

procedure set_position(natural window_line, positive_int column)
-- convert relative position within window to absolute screen position
-- window_line 0 is status line, window_line 1 is first line of text
    position(window_base + window_line, column)
end procedure

natural edit_tab_width

function tab(natural tab_width, positive_int pos)
-- compute new column position after a tab
    return (floor((pos - 1) / tab_width) + 1) * tab_width + 1
end function

function expand_tabs(natural tab_width, sequence line)
-- replace tabs by blanks in a line of text
    natural tab_pos, column, ntabs

    column = 1
    while TRUE do
    tab_pos = find('\t', line[column..length(line)])
    if tab_pos = 0 then
        -- no more tabs
        return line
    else
        tab_pos = tab_pos + column - 1
    end if
    column = tab(tab_width, tab_pos)
    ntabs = 1
    while line[tab_pos+ntabs] = '\t' do
        ntabs = ntabs + 1
        column = column + tab_width
    end while
    -- replace consecutive tabs by blanks
    line = line[1..tab_pos-1] &
           repeat(' ', column - tab_pos) &
           line[tab_pos+ntabs..length(line)]
    end while
end function

function indent_tabs(natural tab_width, sequence line)
-- replace leading blanks of a line with tabs
    natural i, blanks

    if length(line) < tab_width then
    return line
    end if
    i = 1
    while line[i] = ' ' do
    i = i + 1
    end while
    blanks = i - 1
    return repeat('\t', floor(blanks / tab_width)) &
       BLANK_LINE[1..remainder(blanks, tab_width)] &
       line[i..length(line)]
end function

function convert_tabs(natural old_width, natural new_width, sequence line)
-- retabulate a line for a new tab size
    if old_width = new_width then
    return line
    end if
    return indent_tabs(new_width, expand_tabs(old_width, line))
end function

-- color display of lines
include syncolor.e

procedure reverse_video()
-- start inverse video
    text_color(TOP_LINE_TEXT_COLOR)
    bk_color(TOP_LINE_BACK_COLOR)
end procedure

procedure normal_video()
-- end inverse video
    text_color(NORMAL_COLOR)
    bk_color(BACKGROUND_COLOR)
end procedure

procedure ClearLine(window_line sline)
-- clear the current line on screen
    scroll(1, window_base + sline, window_base + sline)
end procedure

procedure ClearWindow()
-- clear the current window
    scroll(window_length, window_base+1, window_base+window_length)
end procedure

procedure ScrollUp(positive_int top, positive_int bottom)
-- move text up one line on screen
    scroll(+1, window_base + top, window_base + bottom)
end procedure

procedure ScrollDown(positive_int top, positive_int bottom)
-- move text down one line on screen
    scroll(-1, window_base + top, window_base + bottom)
end procedure

procedure DisplayLine(buffer_line bline, window_line sline, boolean all_clear)
-- display a buffer line on a given line on the screen
    sequence this_line
    natural last

    this_line = expand_tabs(edit_tab_width, buffer[bline])
    last = length(this_line) - 1
    set_position(sline, 1)
    if multi_color then
    -- color display
    DisplayColorLine(this_line)
    else
    -- monochrome display
    puts(SCREEN, this_line[1..last])
    end if
    if last > SCREEN_WIDTH then
    -- line too long
    set_position(sline, SCREEN_WIDTH)
    text_color(BACKGROUND_COLOR)
    bk_color(NORMAL_COLOR)
    puts(SCREEN, this_line[SCREEN_WIDTH])
    normal_video()
    elsif not all_clear then
    puts(SCREEN, BLANK_LINE)
    end if
end procedure

procedure DisplayWindow(positive_int bline, window_line sline)
-- print a series of buffer lines, starting at sline on screen
-- and continue until the end of screen, or end of buffer
    boolean all_clear

    if sline = 1 then
    ClearWindow()
    all_clear = TRUE
    else
    all_clear = FALSE
    end if

    for b = bline to length(buffer) do
    DisplayLine(b, sline, all_clear)
    if sline = window_length then
        return
    else
        sline = sline + 1
    end if
    end for
    -- blank any remaining screen lines after end of file
    for s = sline to window_length do
    ClearLine(s)
    end for
end procedure

function clean(sequence line)
-- replace control characters with a graphics character
    integer c

    for i = 1 to length(line) do
    c = line[i]
    if c < 32 then
        if c != '\n' then
        if c != '\t' then
            line[i] = CONTROL_CHAR
            control_chars = TRUE
        end if
        end if
    end if
    end for
    if line[length(line)] != '\n' then
    line = line & '\n'
    end if
    return line
end function

function add_line(file_number file_no)
-- add a new line to the buffer
    object line

    line = gets(file_no)

    if atom(line) then
    -- end of file
    return FALSE
    end if

    line = convert_tabs(STANDARD_TAB_WIDTH, edit_tab_width, clean(line))
    buffer = append(buffer, line)
    return TRUE
end function

procedure new_buffer()
-- make room for a new (empty) buffer
    buffer_list = buffer_list & 0 -- place holder for new buffer
    buffer_number = length(buffer_list)
    buffer = {}
end procedure

procedure read_file(file_number file_no)
-- read the entire file into buffer variable

    -- read and immediately display the first screenful
    for i = 1 to window_length do
    if not add_line(file_no) then
        exit
    end if
    end for
    DisplayWindow(1, 1)

    -- read the rest
    while add_line(file_no) do
    end while

end procedure

procedure set_top_line(sequence message)
-- print message on top line
    set_position(0, 1)
    reverse_video()
    puts(SCREEN, message & BLANK_LINE)
    set_position(0, length(message)+1)
end procedure

procedure save_file(sequence file_name)
-- write buffer back into the disk file
    file_number file_no

    if control_chars then
    set_top_line("")
    printf(SCREEN, "%s: control chars were changed to " & CONTROL_CHAR &
               " - save anyway? ", {file_name})
    if not find('y', key_gets("yn")) then
        stop = FALSE
        return
    end if
    end if
    set_top_line("")
    file_no = open(file_name, "w")
    if file_no = -1 then
    printf(SCREEN, "Can't save %s - write permission denied",
          {file_name})
    stop = FALSE
    return
    end if
    printf(SCREEN, "saving %s ... ", {file_name})
    for i = 1 to length(buffer) do
    puts(file_no,
         convert_tabs(edit_tab_width, STANDARD_TAB_WIDTH, buffer[i]))
    end for
    close(file_no)
    puts(SCREEN, "ok")
    clear_modified()
    stop = TRUE
end procedure

procedure arrow_right()
-- action for right arrow key

    positive_int temp_col

    if b_col < length(buffer[b_line]) then
    if buffer[b_line][b_col] = '\t' then
        temp_col = tab(edit_tab_width, s_col)
    else
        temp_col = s_col + 1
    end if
    if temp_col > SCREEN_WIDTH then
        return
    end if
    s_col = temp_col
    b_col = b_col + 1
    end if
end procedure

procedure arrow_left()
-- action for left arrow key

    positive_int old_b_col

    old_b_col = b_col
    b_col = 1
    s_col = 1
    for i = 1 to old_b_col - 2 do
    arrow_right()
    end for
end procedure

procedure skip_white()
-- set cursor to first non-whitespace in line
    positive_int temp_col

    while find(buffer[b_line][b_col], " \t") do
    temp_col = s_col
    arrow_right()
    if s_col = temp_col then
        return -- can't move any further right
    end if
    end while
end procedure

procedure arrow_up()
-- action for up arrow key

    b_col = 1
    s_col = 1
    if b_line > 1 then
    b_line = b_line - 1
    if s_line > 1 then
        s_line = s_line - 1
    else
        -- move all lines down, display new line at top
        ScrollDown(1, window_length)
        DisplayLine(b_line, 1, TRUE)
        set_position(1, 1)
        s_line = 1
    end if
    skip_white()
    end if
end procedure

procedure arrow_down()
-- action for down arrow key
    b_col = 1
    s_col = 1
    if b_line < length(buffer) then
    b_line = b_line + 1
    if s_line < window_length then
        s_line = s_line + 1
    else
        -- move all lines up, display new line at bottom
        ScrollUp(1, window_length)
        DisplayLine(b_line, window_length, TRUE)
    end if
    skip_white()
    end if
end procedure

function numeric(sequence string)
-- convert digit string to an integer
    atom n

    n = 0
    for i = 1 to length(string) do
    if string[i] >= '0' and string[i] <= '9' then
        n = n * 10 + string[i] - '0'
        if not integer(n) then
        return 0
        end if
    else
        exit
    end if
    end for
    return n
end function

procedure goto_line(integer new_line, integer new_col)
-- move to a specified line and column
-- refresh screen if line is 0
    integer new_s_line
    boolean refresh

    if length(buffer) = 0 then
    ClearWindow()
    s_line = 1
    s_col = 1
    return
    end if
    if new_line = 0 then
    new_line = b_line
    refresh = TRUE
    else
    refresh = FALSE
    end if
    if new_line < 1 then
    new_line = 1
    elsif new_line > length(buffer) then
    new_line = length(buffer)
    end if
    new_s_line = new_line - b_line + s_line
    b_line = new_line
    if not refresh and window_line(new_s_line) then
    -- new line is on the screen
    s_line = new_s_line
    else
    -- new line is off the screen, or refreshing
    set_position(1, 1)
    s_line = floor((window_length+1)/2)
    if s_line > b_line or length(buffer) < window_length then
        s_line = b_line
    elsif b_line > length(buffer) - window_length + s_line then
        s_line = window_length - (length(buffer) - b_line)
    end if
    DisplayWindow(b_line - s_line + 1, 1)
    end if
    b_col = 1
    s_col = 1
    set_position(s_line, s_col)
    for i = 1 to new_col-1 do
    arrow_right()
    end for
end procedure

procedure page_down()
-- action for page-down key
    buffer_line prev_b_line

    if length(buffer) <= window_length then
    return
    end if
    prev_b_line = b_line
    b_col = 1
    s_col = 1
    if b_line + window_length + window_length - s_line <= length(buffer) then
    b_line = b_line + window_length
    else
    b_line = length(buffer) - (window_length - s_line)
    end if
    if b_line != prev_b_line then
    DisplayWindow(b_line - s_line + 1, 1)
    end if
end procedure

procedure page_up()
-- action for page-up key
    buffer_line prev_b_line

    if length(buffer) <= window_length then
    return
    end if
    prev_b_line = b_line
    b_col = 1
    s_col = 1
    if b_line - window_length >= s_line then
    b_line = b_line - window_length
    else
    b_line = s_line
    end if
    if b_line != prev_b_line then
    DisplayWindow(b_line - s_line + 1, 1)
    end if
end procedure

procedure set_f_line(natural w, sequence comment)
-- show F-key & file_name
    sequence f_key, text

    if length(window_list) = 1 then
    f_key = ""
    elsif w = 10 then
    f_key = "F10: "
    else
    f_key = 'F' & ('0' + w) & ": "
    end if
    set_top_line(' ' & f_key & file_name & comment)
    text = "Esc for commands"
    set_position(0, SCREEN_WIDTH - length(text))
    puts(SCREEN, text)
end procedure

constant W_BUFFER_NUMBER = 1,
     W_MY_BUFFER_VERSION = 2,
     W_WINDOW_BASE = 3,
     W_WINDOW_LENGTH = 4,
     W_B_LINE = 10

procedure save_state()
-- save current state variables for a window
    window_list[window_number] = {buffer_number, buffer_version, window_base,
                  window_length, auto_complete, multi_color,
                  dot_e, control_chars, file_name, b_line,
                  b_col, s_line, s_col, edit_tab_width}
    buffer_list[buffer_number] = {buffer, modified, buffer_version}
end procedure

procedure restore_state(window_id w)
-- restore state variables for a window
    sequence state
    sequence buffer_info

    -- set up new buffer
    state = window_list[w]
    window_number = w
    buffer_number =  state[W_BUFFER_NUMBER]
    buffer_info = buffer_list[buffer_number]
    buffer = buffer_info[1]
    modified = buffer_info[2]
    buffer_version = buffer_info[3]
    buffer_list[buffer_number] = 0 -- save space

    -- restore other variables
    my_buffer_version = state[2]
    window_base = state[3]
    window_length = state[4]
    auto_complete = state[5]
    multi_color = state[6]
    dot_e = state[7]
    control_chars = state[8]
    file_name = state[9]
    edit_tab_width = state[14]
    set_f_line(w, "")
    normal_video()
    if buffer_version != my_buffer_version then
    -- buffer has changed since we were last in this window
    -- or window size has changed
    if state[W_B_LINE] > length(buffer) then
        if length(buffer) = 0 then
        b_line = 1
        else
        b_line = length(buffer)
        end if
    else
        b_line = state[W_B_LINE]
    end if
    goto_line(0, 1)
    else
    b_line = state[W_B_LINE]
    b_col = state[11]
    s_line = state[12]
    s_col = state[13]
    set_position(s_line, s_col)
    end if
end procedure

procedure refresh_other_windows(positive_int w)
-- redisplay all windows except w

    normal_video()
    for i = 1 to length(window_list) do
    if i != w then
        restore_state(i)
        set_f_line(i, "")
        normal_video()
        goto_line(0, b_col)
        save_state()
    end if
    end for
end procedure

procedure set_window_size()
-- set sizes for windows
    natural nwindows, lines, base, size

    nwindows = length(window_list)
    lines = screen_length - nwindows
    base = 1
    for i = 1 to length(window_list) do
    size = floor(lines / nwindows)
    window_list[i][W_WINDOW_BASE] = base
    window_list[i][W_WINDOW_LENGTH] = size
    window_list[i][W_MY_BUFFER_VERSION] = -1 -- force redisplay
    base = base + size + 1
    nwindows = nwindows - 1
    lines = lines - size
    end for
end procedure

procedure clone_window()
-- set up a new window that is a clone of the current window
-- save state of current window
    window_id w

    if length(window_list) >= MAX_WINDOWS then
    return
    end if
    save_state()
    -- create a place for new window
    window_list = window_list[1..window_number] &
          {window_list[window_number]} &  -- the new clone window
          window_list[window_number+1..length(window_list)]
    w = window_number + 1
    set_window_size()
    refresh_other_windows(w)
    restore_state(w)
end procedure

procedure switch_window(integer new_window_number)
-- switch context to a new window on the screen

    if new_window_number != window_number then
    save_state()
    restore_state(new_window_number)
    end if
end procedure

function delete_window()
-- delete the current window
    boolean buff_in_use

    buffer_list[buffer_number] = {buffer, modified, buffer_version}
    window_list = window_list[1..window_number-1] &
          window_list[window_number+1..length(window_list)]
    buff_in_use = FALSE
    for i = 1 to length(window_list) do
    if window_list[i][W_BUFFER_NUMBER] = buffer_number then
        buff_in_use = TRUE
        exit
    end if
    end for
    if not buff_in_use then
    buffer_list[buffer_number] = 0 -- discard the buffer
    end if
    if length(window_list) = 0 then
    return TRUE
    end if
    set_window_size()
    refresh_other_windows(1)
    window_number = 1
    restore_state(window_number)
    set_position(s_line, s_col)
    return FALSE
end function

procedure new_screen_length()
-- set new number of lines on screen
    natural nlines
    window_id w

    set_top_line("How many lines on screen? (25, 28, 43, 50) ")
    nlines = numeric(key_gets(""))
    if nlines then
    screen_length = text_rows(nlines)
    if screen_length != nlines then
        sound(500)
    end if
    w = window_number
    save_state()
    set_window_size()
    refresh_other_windows(w)
    restore_state(w)
    if screen_length != nlines then
        sound(0)
    end if
    end if
end procedure

-- searching/replacing variables
boolean searching, replacing, match_case
searching = FALSE
replacing = FALSE
match_case = TRUE

sequence find_string -- current (default) string to look for
find_string = ""

sequence replace_string -- current (default) string to replace with
replace_string = ""

procedure replace()
-- replace find_string by replace_string
-- we are currently positioned at the start of an occurrence of find_string
    sequence line

    set_modified()
    line = buffer[b_line]
    line = line[1..b_col-1] & replace_string & line[b_col+length(find_string)..
                        length(line)]
    buffer[b_line] = line
    -- position at end of replacement string
    for i = 1 to length(replace_string)-1 do
    arrow_right()
    end for
    DisplayLine(b_line, s_line, FALSE)
end procedure

function lower(sequence s)
-- convert to lower case
    integer c
    for i = 1 to length(s) do
    c = s[i]
    if c >= 'A' then
        if c <= 'Z' then
        s[i] = c + 'a' - 'A'
        end if
    end if
    end for
    return s
end function

function alphabetic(object s)
-- does s contain alphabetic characters?
    return find(TRUE, (s >= 'A' and s <= 'Z') or
              (s >= 'a' and s <= 'z'))
end function

function case_match(sequence string, sequence text)
-- Find string in text with
-- either case-sensitive or non-case-sensitive comparison
    if match_case then
    return match(string, text)
    else
    return match(lower(string), lower(text))
    end if
end function

function search(boolean continue)
-- find a string from here to the end of the file
-- return TRUE if string is found
    natural col
    sequence temp_find_string, temp_replace_string
    sequence pos

    set_top_line("")
    if length(buffer) = 0 then
    puts(SCREEN, "buffer empty")
    return FALSE
    end if
    if length(find_string) = 0 then
    puts(SCREEN, "searching for:")
    else
    printf(SCREEN, "searching for \"%s\":", {find_string})
    end if
    if not continue then
    pos = get_position()
    temp_find_string = key_gets("")
    if length(temp_find_string) > 0 then
        -- new string typed in
        find_string = temp_find_string
        if alphabetic(find_string) then
        set_position(0, pos[2]+length(temp_find_string)+3)
        puts(SCREEN, "match case? y")
        pos = get_position()
        set_position(0, pos[2] - 1)
        match_case = not find('n', key_gets(""))
        end if
    end if
    if replacing then
        set_top_line("")
        if length(replace_string) = 0 then
        puts(SCREEN, "replace with:")
        else
        printf(SCREEN, "replace with \"%s\":", {replace_string})
        end if
        temp_replace_string = key_gets("")
        if length(temp_replace_string) > 0 then
        replace_string = temp_replace_string
        end if
    end if
    end if

    normal_video()
    if length(find_string) = 0 then
    return FALSE
    end if
    col = case_match(find_string, buffer[b_line][b_col+1..length(buffer[b_line])])
    if col and s_col < SCREEN_WIDTH then
    -- found it on this line after current position
    for i = 1 to col do
        arrow_right()
    end for
    if replacing then
        replace()
    end if
    return TRUE
    else
    -- check lines following this one
    for b = b_line+1 to length(buffer) do
        col = case_match(find_string, buffer[b])
        if col then
        goto_line(b, 1)
        for i = 1 to col - 1 do
           arrow_right()
        end for
        if replacing and s_col < SCREEN_WIDTH then
            replace()
        end if
        set_top_line("")
        printf(SCREEN, "searching for \"%s\":", {find_string})
        return TRUE
        end if
    end for
    set_top_line("")
    printf(SCREEN, "\"%s\" not found", {find_string})
    if alphabetic(find_string) then
        if match_case then
        puts(SCREEN, "  (case must match)")
        else
        puts(SCREEN, "  (any case)")
        end if
    end if
    end if
    return FALSE
end function

procedure show_message()
-- display error message from ex.err
    if length(error_message) > 0 then
    set_top_line(error_message)
    normal_video()
    end if
    set_position(s_line, s_col)
end procedure

procedure set_err_pointer()
-- set cursor at point of error

    for i = 1 to SCREEN_WIDTH do
    if s_col >= start_col then
        exit
    end if
    arrow_right()
    end for
end procedure

function delete_trailing_white(sequence name)
-- get rid of blanks, tabs, newlines at end of string
    while length(name) > 0 do
    if find(name[length(name)], "\n\r\t ") then
        name = name[1..length(name)-1]
    else
        exit
    end if
    end while
    return name
end function

function get_err_line()
-- try to get file name & line number from ex.err
-- returns file_name, sets start_line, start_col, error_message

    file_number err_file
    sequence file_name
    sequence err_lines
    object temp_line
    natural colon_pos

    err_file = open("ex.err", "r")
    if err_file = -1 then
    error_message = ""
    else
    -- read the top of the ex.err error message file
    err_lines = {}
    while length(err_lines) < 5 do
        temp_line = gets(err_file)
        if atom(temp_line) then
        exit
        end if
        err_lines = append(err_lines, temp_line)
    end while
    close(err_file)
    -- look for file name, line, column and error message
    if length(err_lines) > 0 then
        if sequence(err_lines[1]) then
        colon_pos = match(".e", err_lines[1])
        if colon_pos then
            if err_lines[1][colon_pos+2] = 'x' then
            colon_pos = colon_pos + 1
            end if
            file_name = err_lines[1][1..colon_pos+1]
            start_line = numeric(err_lines[1][colon_pos+3..
                              length(err_lines[1])])
            error_message = delete_trailing_white(err_lines[2])
            if length(err_lines) > 3 then
            start_col = find('^', expand_tabs(STANDARD_TAB_WIDTH,
                          err_lines[length(err_lines)-1]))
            end if
            return file_name
        end if
        end if
    end if
    end if
    return ""
end function

function last_use()
-- return TRUE if current buffer
-- is only referenced by the current window
    natural count

    count = 0
    for i = 1 to length(window_list) do
    if window_list[i][W_BUFFER_NUMBER] = buffer_number then
        count = count + 1
        if count = 2 then
        return FALSE
        end if
    end if
    end for
    return TRUE
end function

procedure shell(sequence command, boolean wait)
-- run a DOS command
    window_id w

    bk_color(BLACK)
    text_color(WHITE)
    clear_screen()
    system(command, wait)
    normal_video()
    while get_key() != -1 do
    -- clear the keyboard buffer
    end while
    w = window_number
    save_state()
    refresh_other_windows(w)
    restore_state(w)
end procedure

procedure first_bold(sequence string)
-- highlight first char
    text_color(TOP_LINE_TEXT_COLOR)
    puts(SCREEN, string[1])
    text_color(TOP_LINE_DIM_COLOR)
    puts(SCREEN, string[2..length(string)])
end procedure

procedure get_escape(boolean help)
-- process escape command
    sequence command, answer, temp_name
    natural line
    object dos_command

    cursor(ED_CURSOR)

    set_top_line("")
    if help then
    command = "h"
    else
    first_bold("help  ")
    first_bold("clone  ")
    first_bold("quit|")
    first_bold("save|")
    first_bold("write|")
    first_bold("new  ")
    if dot_e then
        first_bold("ex|")
    end if
    first_bold("dos  ")
    first_bold("find|")
    first_bold("replace  ")
    first_bold("lines  ")
    text_color(TOP_LINE_TEXT_COLOR)
    puts(SCREEN, "ddd  CR: ")
    command = key_gets("hcqswnedfrl") & ' '
    end if

    if command[1] = 'f' then
    replacing = FALSE
    searching = search(FALSE)

    elsif command[1] = 'r' then
    replacing = TRUE
    searching = search(FALSE)

    elsif command[1] = 'q' then
    if modified and last_use() then
        set_top_line("quit without saving changes? ")
        if find('y', key_gets("yn")) then
        stop = delete_window()
        end if
    else
        stop = delete_window()
    end if

    elsif command[1] = 'c' then
    clone_window()

    elsif command[1] = 'n' then
    if modified and last_use() then
        set_top_line("")
        printf(SCREEN, "save changes to %s? ", {file_name})
        if find('y', key_gets("yn")) then
        save_file(file_name)
        end if
    end if
    save_state()
    set_top_line("new file name? ")
    temp_name = delete_trailing_white(key_gets(""))
    if length(temp_name) != 0 then
        file_name = temp_name
        stop = TRUE
    end if

    elsif command[1] = 'w' then
    save_file(file_name)
    stop = FALSE

    elsif command[1] = 's' then
    save_file(file_name)
    if stop then
        stop = delete_window()
    end if

    elsif command[1] = 'e' and dot_e then
    if modified then
        save_file(file_name)
        stop = FALSE
    end if
    -- execute the current file & return
    if sequence(dir("ex.err")) then
        system("del ex.err > NUL", 0)
    end if
    shell("ex " & file_name, TRUE)
    goto_line(0, b_col)
    if compare(file_name, get_err_line()) = 0 then
        goto_line(start_line, 1)
        set_err_pointer()
        show_message()
    end if

    elsif command[1] = 'd' then
    set_top_line("DOS command? ")
    dos_command = key_gets("")
    shell(dos_command, TRUE)
    goto_line(0, b_col) -- refresh screen

    elsif command[1] = 'h' then
    dos_command = getenv("EUDIR")
    if atom(dos_command) then
        -- Euphoria hasn't been installed yet
        set_top_line("EUDIR not set. See install.doc")
    else
        dos_command = "ed.bat " & dos_command & "\\DOC"
        if help then
        set_top_line(
        "That key does nothing - do you want to view the help text? ")
        answer = key_gets("yn") & ' '
        if answer[1] != 'n' and answer[1] != 'N' then
            answer = "e"
        end if
        else
        set_top_line("ed.doc, refman.doc, or library.doc? (e, r or l): ")
        answer = key_gets("erl") & ' '
        end if
        if answer[1] = 'r' then
        shell(dos_command & "\\REFMAN.DOC", FALSE)
        goto_line(0, b_col)
        elsif answer[1] = 'e' then
        shell(dos_command & "\\ED.DOC", FALSE)
        goto_line(0, b_col)
        elsif answer[1] = 'l' then
        shell(dos_command & "\\LIBRARY.DOC", FALSE)
        goto_line(0, b_col)
        else
        normal_video()
        end if
    end if

    elsif command[1] = 'l' then
    new_screen_length()

    elsif command[1] >= '0' and command[1] <= '9' then
    line = numeric(command)
    normal_video()
    goto_line(line, 1)
    if not buffer_line(line) then
        set_top_line("")
        printf(SCREEN, "lines are 1..%d", length(buffer))
    end if

    else
    set_top_line("")
    if length(buffer) = 0 then
        puts(SCREEN, "empty buffer")
    else
        printf(SCREEN, "%s line %d of %d, column %d of %d, ",
               {file_name, b_line, length(buffer), s_col,
            length(expand_tabs(edit_tab_width, buffer[b_line]))-1})
        if modified then
        puts(SCREEN, "modified")
        else
        puts(SCREEN, "not modified")
        end if
    end if
    end if

    normal_video()
end procedure

procedure insert(char key)
-- insert a character into the current line at the current position

    sequence tail
    positive_int new_col

    set_modified()
    tail = buffer[b_line][b_col..length(buffer[b_line])]
    if key = CR or key = '\n' then
    -- truncate this line and create a new line using tail
    buffer[b_line] = buffer[b_line][1..b_col-1] & '\n'
    buffer = append(buffer[1..b_line], tail) &
            buffer[b_line+1..length(buffer)]
    if s_line = window_length then
        arrow_down()
        arrow_up()
    else
        ScrollDown(s_line+1, window_length)
    end if
    if window_length = 1 then
        arrow_down()
    else
        DisplayLine(b_line, s_line, FALSE)
        b_line = b_line + 1
        s_line = s_line + 1
        DisplayLine(b_line, s_line, FALSE)
    end if
    s_col = 1
    b_col = 1
    else
    if key = '\t' then
        new_col = tab(edit_tab_width, s_col)
    else
        new_col = s_col + 1
    end if
    if new_col > SCREEN_WIDTH then
        return
    else
        s_col = new_col
    end if
    buffer[b_line] = buffer[b_line][1..b_col-1] & key & tail
    DisplayLine(b_line, s_line, TRUE)
    b_col = b_col + 1
    end if
    set_position(s_line, s_col)
end procedure

procedure insert_string(sequence text)
-- insert a bunch of characters at the current position
    natural save_line, save_col

    save_line = b_line
    save_col = b_col
    for i = 1 to length(text) do
    if text[i] = CR or text[i] = '\n' then
        insert(text[i])
    else
        buffer[b_line] = buffer[b_line][1..b_col-1] & text[i] &
                 buffer[b_line][b_col..length(buffer[b_line])]
        b_col = b_col + 1
        if i = length(text) then
        DisplayLine(b_line, s_line, FALSE)
        end if
    end if
    end for
    goto_line(save_line, save_col)
end procedure

-- expandable words & corresponding text
constant expand_word = {"if", "for", "while", "elsif",
            "procedure", "type", "function"},

     expand_text = {" then",  "=  to  by  do",  " do",  " then",
            "()",  "()",  "()"
               }

procedure try_auto_complete(char key)
-- check for a keyword that can be automatically completed
    sequence word, this_line, white_space, leading_white, begin
    natural first_non_blank, wordnum

    if key = ' ' then
    insert(key)
    end if
    this_line = buffer[b_line]
    white_space = this_line = ' ' or this_line = '\t'
    first_non_blank = find(0, white_space) -- there's always '\n' at end
    leading_white = this_line[1..first_non_blank - 1]
    if auto_complete and first_non_blank < b_col - 2 then
    if not find(0, white_space[b_col..length(white_space)-1]) then
        word = this_line[first_non_blank..b_col - 1 - (key = ' ')]
        wordnum = find(word, expand_word)

        if key = CR and compare(word, "else") = 0 then
         leading_white = leading_white & '\t'

        elsif wordnum > 0 then
        sound(1000)
        -- expandable word (only word on line)

        begin = expand_text[wordnum] & CR & leading_white

        if compare(word, "elsif") = 0 then
            insert_string(begin & '\t')

        elsif find(word, {"function", "type"}) then
            insert_string(begin & CR &
                  leading_white & "\treturn" & CR &
                  "end " & expand_word[wordnum])
        else
            insert_string(begin & '\t' & CR &
                  leading_white &
                  "end " & expand_word[wordnum])
        end if
        delay(0.07) -- or beep is too short
        sound(0)
        end if
    end if
    end if
    if key = CR then
    if b_col >= first_non_blank then
        buffer[b_line] = buffer[b_line][1..b_col-1] & leading_white &
                 buffer[b_line][b_col..length(buffer[b_line])]
        insert(CR)
        skip_white()
    else
        insert(CR)
    end if
    end if
end procedure

procedure insert_kill_buffer()
-- insert the kill buffer at the current position
-- kill buffer could be a sequence of lines or a sequence of characters

    if length(kill_buffer) = 0 then
    return
    end if
    if atom(kill_buffer[1]) then
    -- inserting a sequence of chars
    insert_string(kill_buffer)
    else
    -- inserting a sequence of lines
    set_modified()
    buffer = buffer[1..b_line - 1] &
         kill_buffer &
         buffer[b_line..length(buffer)]
    DisplayWindow(b_line, s_line)
    b_col = 1
    s_col = 1
    end if
end procedure

procedure delete_line(buffer_line dead_line)
-- delete a line from the buffer and update the display if necessary

    integer x

    set_modified()
    buffer = buffer[1..dead_line-1] & buffer[dead_line+1..length(buffer)]
    x = dead_line - b_line + s_line
    if window_line(x) then
    -- dead line is on the screen at line x
    ScrollUp(x, window_length)
    if length(buffer) - b_line >= window_length - s_line then
        -- show new line at bottom
        DisplayLine(b_line + window_length - s_line, window_length, TRUE)
    end if
    end if
    if b_line > length(buffer) then
    arrow_up()
    else
    b_col = 1
    s_col = 1
    end if
    adding_to_kill = TRUE
end procedure

procedure delete_char()
-- delete the character at the current position
    char dchar
    sequence head
    natural save_b_col

    set_modified()
    dchar = buffer[b_line][b_col]
    head = buffer[b_line][1..b_col - 1]
    if dchar = '\n' then
    if b_line < length(buffer) then
        -- join this line with the next one and delete the next one
        buffer[b_line] = head & buffer[b_line+1]
        DisplayLine(b_line, s_line, FALSE)
        save_b_col = b_col
        delete_line(b_line + 1)
        for i = 1 to save_b_col - 1 do
        arrow_right()
        end for
    else
        if length(buffer[b_line]) = 1 then
        delete_line(b_line)
        else
        arrow_left() -- a line must always end with \n
        end if
    end if
    else
    buffer[b_line] = head & buffer[b_line][b_col+1..length(buffer[b_line])]
    if length(buffer[b_line]) = 0 then
        delete_line(b_line)
    else
        DisplayLine(b_line, s_line, FALSE)
        if b_col > length(buffer[b_line]) then
        arrow_left()
        end if
    end if
    end if
    adding_to_kill = TRUE
end procedure

function good(extended_char key)
-- return TRUE if key should be processed
    if find(key, CONTROL_CHARS) then
    return TRUE
    elsif (key >= ' ' and key <= 127) then
    return TRUE
    elsif key = '\t' or key = CR then
    return TRUE
    else
    return FALSE
    end if
end function

procedure edit_file()
-- edit the file in buffer
    extended_char key

    if length(buffer) > 0 then
    if start_line > 0 then
        if start_line > length(buffer) then
        start_line = length(buffer)
        end if
        goto_line(start_line, 1)
        set_err_pointer()
        show_message()
    end if
    end if

    -- speed up keyboard repeat rate:
    -- system("mode con rate=30 delay=2", 2)

    cursor(ED_CURSOR)
    stop = FALSE

    while not stop do

    key = wait_key()

    if good(key) then
        -- normal key

        if key >= F1 and key <= F10 then
        if key < F1 + length(window_list) then
            switch_window(key - F1 + 1)
        else
            set_top_line("")
            printf(SCREEN, "F%d is not an active window", key - F1 + 1)
            normal_video()
        end if
        adding_to_kill = FALSE

        elsif length(buffer) = 0 and key != ESCAPE then
        -- empty buffer
        -- only allowed action is to insert something
        if key = INSERT or not find(key, CONTROL_CHARS) then
            -- initialize buffer
            buffer = {{'\n'}} -- one line with \n
            b_line = 1
            b_col = 1
            s_line = 1
            s_col = 1
            if key = INSERT then
            insert_kill_buffer()
            else
            insert(key)
            end if
            DisplayLine(1, 1, FALSE)
        end if

        elsif key = DELETE then
        if not adding_to_kill then
            kill_buffer = {buffer[b_line][b_col]}
        elsif sequence(kill_buffer[1]) then
            -- we were building up deleted lines,
            -- but now we'll switch to chars
            kill_buffer = {buffer[b_line][b_col]}
        else
            kill_buffer = append(kill_buffer, buffer[b_line][b_col])
        end if
        delete_char()

        elsif key = CONTROL_DELETE or key = CONTROL_D then
        if not adding_to_kill then
            kill_buffer = {buffer[b_line]}
        elsif atom(kill_buffer[1]) then
            -- we were building up deleted chars,
            -- but now we'll switch to lines
            kill_buffer = {buffer[b_line]}
        else
            kill_buffer = append(kill_buffer, buffer[b_line])
        end if
        delete_line(b_line)

        else
        if key = PAGE_DOWN then
            page_down()

        elsif key = PAGE_UP then
            page_up()

        elsif key = ARROW_LEFT then
            arrow_left()

        elsif key = ARROW_RIGHT then
            arrow_right()

        elsif key = ARROW_DOWN then
            arrow_down()

        elsif key = ARROW_UP then
            arrow_up()

        elsif key = ' ' then
            try_auto_complete(key)

        elsif key = INSERT then
            insert_kill_buffer()

        elsif key = BS then
            arrow_left()
            delete_char()

        elsif key = HOME then
            goto_line(1, 1)

        elsif key = END then
            goto_line(length(buffer), 1)

        elsif key = ESCAPE then
            -- special command
            get_escape(FALSE)

        elsif key = CR then
            if searching then
            searching = search(TRUE)
            normal_video()
            searching = TRUE -- avoids accidental <CR> insertion
            else
            try_auto_complete(key)
            end if

        else
            insert(key)

        end if

        adding_to_kill = FALSE

        end if

        if key != CR and key != ESCAPE then
        searching = FALSE
        end if
        cursor(ED_CURSOR)
        set_position(s_line, s_col)

    else
        -- illegal key pressed
        get_escape(TRUE)  -- give him some help
        set_position(s_line, s_col)
    end if
    end while
end procedure

procedure ed(sequence command)
-- editor main procedure
-- start editing a new file
-- ed.ex is executed by ed.bat
-- command line will be:
--    ex ed.ex              - get filename from ex.err, or user
--    ex ed.ex filename     - filename specified

    file_number file_no

    start_line = 0
    start_col = 0

    if length(command) >= 3 then
    file_name = lower(command[3])
    else
    file_name = get_err_line()
    end if
    if length(file_name) = 0 then
    -- we still don't know the file name - so ask user
    puts(SCREEN, "file name? ")
    cursor(ED_CURSOR)
    file_name = key_gets("")
    puts(SCREEN, '\n')
    end if
    file_name = delete_trailing_white(file_name)
    if length(file_name) = 0 then
    abort(1) -- file_name was just whitespace - quit
    end if
    file_no = open(file_name, "r")

    -- turn off multi_color & auto_complete for non .e files
    multi_color = WANT_COLOR_SYNTAX
    auto_complete = WANT_AUTO_COMPLETE
    if not config[VC_COLOR] or config[VC_MODE] = 7 then
    multi_color = FALSE -- mono monitor
    end if
    file_name = file_name & ' '
    dot_e = FALSE
    for i = 1 to length(E_FILES) do
    if match(E_FILES[i] & ' ', file_name) then
        dot_e = TRUE
    end if
    end for
    if not dot_e then
    multi_color = FALSE
    auto_complete = FALSE
    end if

    -- use PROG_INDENT tab width for Euphoria & other languages:
    edit_tab_width = STANDARD_TAB_WIDTH
    for i = 1 to length(PROG_FILES) do
       if match(PROG_FILES[i] & ' ', file_name) then
       edit_tab_width = PROG_INDENT
       exit
       end if
    end for

    file_name = file_name[1..length(file_name)-1] -- remove ' '
    if multi_color then
    init_class()
    end if

    adding_to_kill = FALSE
    clear_modified()
    buffer_version = 0
    control_chars = FALSE
    wrap(0)
    new_buffer()
    s_line = 1
    s_col = 1
    b_line = 1
    b_col = 1
    save_state()
    if file_no = -1 then
    set_f_line(window_number, " <new file>")
    normal_video()
    ClearWindow()
    else
    set_f_line(window_number, "")
    normal_video()
    set_position(1, 1)
    cursor(NO_CURSOR)
    read_file(file_no)
    close(file_no)
    end if
    set_position(1, 1)
    edit_file()
end procedure

procedure ed_main()
-- startup and shutdown of ed()
    sequence cl

    config = video_config()

    if config[VC_XPIXELS] > 0 then
    if graphics_mode(3) then
    end if
    config = video_config()
    end if

    if config[VC_LINES] != INITIAL_LINES then
    screen_length = text_rows(INITIAL_LINES)
    config = video_config()
    end if
    screen_length = config[VC_LINES]
    window_length = screen_length - 1

    cl = command_line()

    while length(window_list) > 0 do
    ed(cl)
    cl = {"ex", "ed.ex" , file_name}
    end while

    -- exit editor
    if screen_length != FINAL_LINES then
    screen_length = text_rows(FINAL_LINES)
    end if
    cursor(UNDERLINE_CURSOR)
    bk_color(BLACK)
    text_color(BLACK)
    position(screen_length, 1)
    puts(SCREEN, BLANK_LINE)
    position(screen_length, 1)
    text_color(WHITE)
    puts(SCREEN, " \n")
end procedure

ed_main()
-- This abort statement reduces the chance of
-- a syntax error when you edit ed.ex using itself:
abort(1)