Better paged print for ComputerCraft using a less-style pager

betterPagedPrint.lua

-- CCPL license: https://github.com/cc-tweaked/CC-Tweaked/blob/mc-1.16.x/LICENSE

-- Note that this breaks help on vanilla CC (CC:T help still works)
textutils.pagedPrint = function(contents, freeLines)

    freeLines = freeLines or 0

    local foldLines = true
    
    local lines = {}
    local pos, hpos = 1, 1
    local w, h = term.getSize()
    local message = nil
    h=h-1
    
    local function readFile()
        lines = {}
        for line in string.gmatch(contents, "[^\n\r]+") do table.insert(lines, ({string.gsub(line, "\t", "    ")})[1]) end
        if foldLines and hpos == 1 then for i = 1, #lines do if #lines[i] > w then
            table.insert(lines, i+1, string.sub(lines[i], w) or "")
            lines[i] = string.sub(lines[i], 1, w - 1)
        end end end
    end
    
    local function redrawScreen()
        term.clear()
        term.setCursorPos(1, 1)
        term.setCursorBlink(false)
        term.setBackgroundColor(colors.black)
        term.setTextColor(colors.white)
        for i = pos, pos + h - 1 do 
            if lines[i] ~= nil then term.write(string.sub(lines[i], hpos)) end 
            term.setCursorPos(1, i - pos + 2)
        end
        term.setCursorPos(1, h+1)
        if message then term.blit(message, string.rep("f", #message), string.rep("0", #message))
        elseif pos >= #lines - h then term.blit("(END)", "fffff", "00000")
        else term.write(":") end
        term.setCursorBlink(true)
    end
    
    local function readCommand(prompt, fg, bg)
        term.setCursorPos(1, h+1)
        term.clearLine()
        term.blit(prompt, fg or string.rep("0", #prompt), bg or string.rep("f", #prompt))
        local str = ""
        local c = 1
        while true do
            term.setCursorPos(#prompt + 1, h + 1)
            term.write(str .. string.rep(" ", w - #str - #prompt - 2))
            term.setCursorPos(#prompt + c, h + 1)
            term.setCursorBlink(true)
            local ev, p1 = os.pullEvent()
            if ev == "key" then
                if p1 == keys.backspace then if str == "" then return nil elseif c > 1 then 
                    str = string.sub(str, 1, c-2) .. string.sub(str, c)
                    c=c-1 
                end
                elseif p1 == keys.left and c > 1 then c = c - 1
                elseif p1 == keys.right and c < #str + 1 then c = c + 1
                elseif p1 == keys.enter or p1 == keys["return"] then return str
                end
            elseif ev == "char" then 
                str = string.sub(str, 1, c-1) .. p1 .. string.sub(str, c) 
                c=c+1
            end
        end
    end
    
    local function flashScreen()
        local br, bg, bb = term.getPaletteColor(colors.black)
        term.setPaletteColor(colors.black, term.getPaletteColor(colors.lightGray))
        sleep(0.1)
        term.setPaletteColor(colors.black, term.getPaletteColor(colors.gray))
        sleep(0.05)
        term.setPaletteColor(colors.black, br, bg, bb)
        sleep(0.05)
    end
    
    readFile()

    if #lines < freeLines then return print(contents) end
    
    local lastQuery = nil
    
    while true do
        redrawScreen()
        local ev, p1, p2, p3 = os.pullEvent()
        local oldMessage = message
        message = nil
        if ev == "key" then
            if p1 == keys.left and hpos > w / 2 then hpos = hpos - w / 2
            elseif p1 == keys.right then hpos = hpos + w / 2
            elseif p1 == keys.up then if pos > 1 then pos = pos - 1 else flashScreen() end
            elseif (p1 == keys.down or p1 == keys.enter or p1 == keys["return"]) then if pos < #lines - h then pos = pos + 1 else flashScreen() end
            elseif p1 == keys.space then if pos < #lines - h then pos = pos + (pos < #lines - 2*h + 1 and h or (#lines - h) - pos) else flashScreen() end
            end
        elseif ev == "char" then
            if p1 == "q" then break 
            elseif p1 == "f" then if pos < #lines - h then pos = pos + (pos < #lines - 2*h + 1 and h or (#lines - h) - pos) else flashScreen() end
            elseif p1 == "b" then if pos > 1 then pos = pos - (pos > h + 1 and h or pos - 1) else flashScreen() end
            elseif p1 == "d" then if pos < #lines - h then pos = pos + (pos < #lines - (1.5*h) + 1 and h / 2 or (#lines - h) - pos) else flashScreen() end
            elseif p1 == "u" then if pos > 1 then pos = pos - (pos > (h / 2) + 1 and (h / 2) or pos - 1) else flashScreen() end
            elseif p1 == "g" or p1 == "<" then pos = 1
            elseif p1 == "G" or p1 == ">" then pos = #lines - h
            elseif p1 == "e" or p1 == "j" then if pos < #lines - h then pos = pos + 1 else flashScreen() end
            elseif p1 == "y" or p1 == "k" then if pos > 1 then pos = pos - 1 else flashScreen() end
            elseif p1 == "K" or p1 == "Y" then pos = pos - 1
            elseif p1 == "J" then pos = pos + 1
            elseif p1 == "/" then
                local query = readCommand("/")
                if query == "" then query = lastQuery end
                if query ~= nil then
                    lastQuery = query
                    local found = false
                    for i = pos + 1, #lines do if string.match(lines[i], query) then
                        pos = i
                        found = true
                        break
                    end end
                    if pos > #lines - h then pos = #lines - h end
                    if not found then message = "Pattern not found" end
                end
            elseif p1 == "?" then
                local query = readCommand("?")
                if query == "" then query = lastQuery end
                if query ~= nil then
                    lastQuery = query
                    local found = false
                    for i = pos - 1, 1, -1 do if string.match(lines[i], query) then
                        pos = i
                        found = true
                        break
                    end end
                    if pos > #lines - h then pos = #lines - h end
                    if not found then message = "Pattern not found" end
                end
            elseif p1 == "n" then
                local found = false
                for i = pos + 1, #lines do if string.match(lines[i], lastQuery) then
                    pos = i
                    found = true
                    break
                end end
                if pos > #lines - h then pos = #lines - h end
                if not found then message = "Pattern not found" end
            elseif p1 == "N" then
                local found = false
                for i = pos - 1, 1, -1 do if string.match(lines[i], lastQuery) then
                    pos = i
                    found = true
                    break
                end end
                if pos > #lines - h then pos = #lines - h end
                if not found then message = "Pattern not found" end
            end
        elseif ev == "term_resize" then
            w, h = term.getSize()
            h=h-1
            readFile()
        elseif ev == "mouse_scroll" then
            if p1 == 1 and pos < #lines - h then pos = pos + 1
            elseif p1 == -1 and pos > 1 then pos = pos - 1 end
        else
            message = oldMessage
        end
    end
    term.clear()
    term.setCursorPos(1, 1)
    term.setTextColor(colors.white)
    term.setBackgroundColor(colors.black)

    return #lines
    
end

local function tabulateCommon( ... )
    local retval = {""}
    local tAll = { ... }
    for k,v in ipairs( tAll ) do
        if type( v ) ~= "number" and type( v ) ~= "table" then
            error( "bad argument #"..k.." (expected number or table, got " .. type( v ) .. ")", 3 ) 
        end
    end
    
    local w,h = term.getSize()
    local nMaxLen = w / 8
    for n, t in ipairs( tAll ) do
        if type(t) == "table" then
            for n, sItem in pairs(t) do
                nMaxLen = math.max( string.len( sItem ) + 1, nMaxLen )
            end
        end
    end
    local nCols = math.floor( w / nMaxLen )
    local nLines = 0
    local function newLine()
        nLines = nLines + 1
        retval[nLines+1] = ""
    end
    
    local function drawCols( _t )
        local nCol = 1
        for n, s in ipairs( _t ) do
            if nCol > nCols then
                nCol = 1
                newLine()
            end

            local cx = #retval[nLines+1]
            cx = ((nCol - 1) * nMaxLen)
            retval[nLines+1] = retval[nLines+1] .. string.rep(" ", cx - #retval[nLines+1]) .. s

            nCol = nCol + 1      
        end
        newLine()
    end
    for n, t in ipairs( tAll ) do
        if type(t) == "table" then
            if #t > 0 then
                drawCols( t )
            end
        elseif type(t) == "number" then
            --term.setTextColor( t )
        end
    end    
    return retval
end

textutils.pagedTabulate = function(...) textutils.pagedPrint(table.concat(tabulateCommon(...), "\n")) end