manual_cycleTrade

inter = peripheral.find("trading_interface")
local tradeList = {}
function getTrades(sMode,targetStr)
    local ret = nil
    inter.cycleTrades()
    ret,tradeList = inter.getTrades();
    for key, value in pairs(tradeList) do
        if value ~= nil then
            local result = value["result"]
            for key, value in pairs(result) do
                if key == "minecraft:enchanted_book" then
                    -- find enchanted_book
                    local enchants = value["enchants"]
                    for key, value in pairs(enchants) do
                        local ret = nil
                        if sMode then
                            local pos = string.find(key,":")
                            key = string.sub(key,pos+1)
                            ret = string.match(key,"^"..targetStr.."$")
                        else
                            ret = string.find(key,targetStr)
                        end
                        if ret ~= nil then
                            return true
                        end
                    end
                end
            end
        end
    end
    return false
end

while true do
    term.clear()
    term.setCursorPos(1,1)
    print("use \"S keywork\" to Strict matching")
    print("or just \"keywork\" to find what word have keyword")
    print("please type the keyword for find enchant_book:")
    local str = io.read()
    if str == "_res" then
        inter.restock()
    else
        local ret = false
        local sFinder = string.match(str,"^[sS][ ]+([%a_]+)[ ]*$")
        local sMode = false
        if sFinder ~= nil then
            sMode = true
            str = sFinder
        else
            str = string.match(str,"^[ ]*([%a_]+)[ ]*$")
        end
        repeat
            ret = getTrades(sMode,str)
        until ret
    end
end