Move paint/edit menu bar into common module

I want to add a menu bar to the edit runner too, so let's make this code
a little more reusable first.

projects/core/src/main/resources/data/computercraft/lua/rom/modules/main/cc/internal/menu.lua

@@ -0,0 +1,125 @@
+-- SPDX-FileCopyrightText: 2017 Daniel Ratcliffe
+--
+-- SPDX-License-Identifier: LicenseRef-CCPL
+
+--[[- A simple menu bar.
+
+> [!DANGER]
+> This is an internal module and SHOULD NOT be used in your own code. It may
+> be removed or changed at any time.
+
+This provides a shared implementation of the menu bar used by the `edit` and
+`paint` programs. This draws a menu bar at the bottom of the string, with a list
+of options.
+
+@local
+]]
+
+local expect = require "cc.expect".expect
+
+--[[- Create a new menu bar.
+
+This should be called every time the menu is displayed.
+
+@tparam { string... } items The menu items to display.
+@return The menu.
+]]
+local function create(items)
+    expect(1, items, "table")
+    return {
+        items = items,
+        selected = 1,
+    }
+end
+
+--[[- Draw the menu bar at the bottom of the screen.
+
+This should be called when first displaying the menu, and if the whole screen is
+redrawn (e.g. after a [`term_resize`]).
+
+@param menu The menu bar to draw.
+]]
+local function draw(menu)
+    expect(1, menu, "table")
+
+    local _, height = term.getSize()
+    term.setCursorPos(1, height)
+
+    term.clearLine()
+
+    local active_colour = term.isColour() and colours.yellow or colours.white
+    term.setTextColour(colours.white)
+    for k, v in pairs(menu.items) do
+        if menu.selected == k then
+            term.setTextColour(active_colour)
+            term.write("[")
+            term.setTextColour(colours.white)
+            term.write(v)
+            term.setTextColour(active_colour)
+            term.write("]")
+            term.setTextColour(colours.white)
+        else
+            term.write(" " .. v .. " ")
+        end
+    end
+end
+
+--[[- Process an event.
+
+@param menu The menu bar to update.
+@tparam string The event name.
+@param ... Additional arguments to the event.
+@treturn nil|boolean|string Either:
+
+  - If no action was taken, return `nil`.
+  - If the menu was closed, return `false`.
+  - If an item was selected, return the item as a string.
+]]
+local function handle_event(menu, event, ...)
+    expect(1, menu, "table")
+
+    if event == "key" then
+        local key = ...
+
+        if key == keys.right then
+            -- Move right
+            menu.selected = menu.selected + 1
+            if menu.selected > #menu.items then menu.selected = 1 end
+            draw(menu)
+        elseif key == keys.left and menu.selected > 1 then
+            -- Move left
+            menu.selected = menu.selected - 1
+            if menu.selected < 1 then menu.selected = #menu.items end
+            draw(menu)
+        elseif key == keys.enter or key == keys.numPadEnter then
+            -- Select an option
+            return menu.items[menu.selected]
+        elseif key == keys.leftCtrl or keys == keys.rightCtrl or keys == keys.rightAlt then
+            -- Cancel the menu
+            return false
+        end
+    elseif event == "char" then
+        -- Select menu items
+        local char = (...):lower()
+        for _, item in pairs(menu.items) do
+            if item:sub(1, 1):lower() == char then return item end
+        end
+    elseif event == "mouse_click" then
+        local _, x, y = ...
+
+        local _, height = term.getSize()
+        if y ~= height then return false end -- Exit the menu
+
+        local item_start = 1
+        for _, item in ipairs(menu.items) do
+            local item_end = item_start + #item + 2
+            if x >= item_start and x < item_end then return item end
+            item_start = item_end
+        end
+    end
+
+    return nil
+end
+
+
+return { create = create, draw = draw, handle_event = handle_event }

projects/core/src/main/resources/data/computercraft/lua/rom/programs/edit.lua

@@ -54,19 +54,19 @@ else
 end
 
 -- Menus
-local bMenu = false
+local menu  = require "cc.internal.menu"
-local nMenuItem = 1
+local current_menu
-local tMenuItems = {}
+local menu_items = {}
 if not bReadOnly then
-    table.insert(tMenuItems, "Save")
+    table.insert(menu_items, "Save")
 end
 if shell.openTab then
-    table.insert(tMenuItems, "Run")
+    table.insert(menu_items, "Run")
 end
 if peripheral.find("printer") then
-    table.insert(tMenuItems, "Print")
+    table.insert(menu_items, "Print")
 end
-table.insert(tMenuItems, "Exit")
+table.insert(menu_items, "Exit")
 
 local status_ok, status_text
 local function set_status(text, ok)
@@ -214,7 +214,7 @@ end
 
 local function recomplete()
     local sLine = tLines[y]
-    if not bMenu and not bReadOnly and x == #sLine + 1 then
+    if not bReadOnly and x == #sLine + 1 then
         tCompletions = complete(sLine)
         if tCompletions and #tCompletions > 0 then
             nCompletion = 1
@@ -281,22 +281,9 @@ local function redrawMenu()
     term.write(y)
 
     term.setCursorPos(1, h)
-    if bMenu then
+    if current_menu then
         -- Draw menu
-        term.setTextColour(textColour)
+        menu.draw(current_menu)
-        for nItem, sItem in pairs(tMenuItems) do
-            if nItem == nMenuItem then
-                term.setTextColour(highlightColour)
-                term.write("[")
-                term.setTextColour(textColour)
-                term.write(sItem)
-                term.setTextColour(highlightColour)
-                term.write("]")
-                term.setTextColour(textColour)
-            else
-                term.write(" " .. sItem .. " ")
-            end
-        end
     else
         -- Draw status
         term.setTextColour(status_ok and highlightColour or errorColour)
@@ -306,6 +293,7 @@ local function redrawMenu()
 
     -- Reset cursor
     term.setCursorPos(x - scrollX, y - scrollY)
+    term.setCursorBlink(not current_menu)
 end
 
 local tMenuFuncs = {
@@ -383,7 +371,8 @@ local tMenuFuncs = {
             end
         end
 
-        bMenu = false
+        local old_menu = current_menu
+        current_menu = nil
         term.redirect(printerTerminal)
         local ok, error = pcall(function()
             term.scroll()
@@ -401,7 +390,7 @@ local tMenuFuncs = {
             redrawMenu()
             sleep(0.5)
         end
-        bMenu = true
+        current_menu = old_menu
 
         if nPage > 1 then
             set_status("Printed " .. nPage .. " Pages")
@@ -442,15 +431,6 @@ local tMenuFuncs = {
     end,
 }
 
-local function doMenuItem(_n)
-    tMenuFuncs[tMenuItems[_n]]()
-    if bMenu then
-        bMenu = false
-        term.setCursorBlink(true)
-    end
-    redrawMenu()
-end
-
 local function setCursor(newX, newY)
     local _, oldY = x, y
     x, y = newX, newY
@@ -513,13 +493,29 @@ local function acceptCompletion()
     end
 end
 
+local function handleMenuEvent(event)
+    assert(current_menu)
+
+    local result = menu.handle_event(current_menu, table.unpack(event, 1, event.n))
+    if result == false then
+        current_menu = nil
+        redrawMenu()
+    elseif result ~= nil then
+        tMenuFuncs[result]()
+        current_menu = nil
+        redrawMenu()
+    end
+end
+
 -- Handle input
 while bRunning do
-    local sEvent, param, param2, param3 = os.pullEvent()
+    local event = table.pack(os.pullEvent())
-    if sEvent == "key" then
+    if event[1] == "key" then
-        if param == keys.up then
+        if current_menu then
-            -- Up
+            handleMenuEvent(event)
-            if not bMenu then
+        else
+            local key = event[2]
+            if key == keys.up then
                 if nCompletion then
                     -- Cycle completions
                     nCompletion = nCompletion - 1
@@ -535,12 +531,8 @@ while bRunning do
                         y - 1
                     )
                 end
-            end
 
-        elseif param == keys.down then
+            elseif key == keys.down then
-            -- Down
-            if not bMenu then
-                -- Move cursor down
                 if nCompletion then
                     -- Cycle completions
                     nCompletion = nCompletion + 1
@@ -556,11 +548,8 @@ while bRunning do
                         y + 1
                     )
                 end
-            end
 
-        elseif param == keys.tab then
+            elseif key == keys.tab and not bReadOnly then
-            -- Tab
-            if not bMenu and not bReadOnly then
                 if nCompletion and x == #tLines[y] + 1 then
                     -- Accept autocomplete
                     acceptCompletion()
@@ -570,11 +559,8 @@ while bRunning do
                     tLines[y] = string.sub(sLine, 1, x - 1) .. "    " .. string.sub(sLine, x)
                     setCursor(x + 4, y)
                 end
-            end
 
-        elseif param == keys.pageUp then
+            elseif key == keys.pageUp then
-            -- Page Up
-            if not bMenu then
                 -- Move up a page
                 local newY
                 if y - (h - 1) >= 1 then
@@ -586,11 +572,7 @@ while bRunning do
                     math.min(x, #tLines[newY] + 1),
                     newY
                 )
-            end
+            elseif key == keys.pageDown then
-
-        elseif param == keys.pageDown then
-            -- Page Down
-            if not bMenu then
                 -- Move down a page
                 local newY
                 if y + (h - 1) <= #tLines then
@@ -600,48 +582,29 @@ while bRunning do
                 end
                 local newX = math.min(x, #tLines[newY] + 1)
                 setCursor(newX, newY)
-            end
 
-        elseif param == keys.home then
+            elseif key == keys.home then
-            -- Home
-            if not bMenu then
                 -- Move cursor to the beginning
                 if x > 1 then
                     setCursor(1, y)
                 end
-            end
 
-        elseif param == keys["end"] then
+            elseif key == keys["end"] then
-            -- End
-            if not bMenu then
                 -- Move cursor to the end
                 local nLimit = #tLines[y] + 1
                 if x < nLimit then
                     setCursor(nLimit, y)
                 end
-            end
 
-        elseif param == keys.left then
+            elseif key == keys.left then
-            -- Left
-            if not bMenu then
                 if x > 1 then
                     -- Move cursor left
                     setCursor(x - 1, y)
                 elseif x == 1 and y > 1 then
                     setCursor(#tLines[y - 1] + 1, y - 1)
                 end
-            else
-                -- Move menu left
-                nMenuItem = nMenuItem - 1
-                if nMenuItem < 1 then
-                    nMenuItem = #tMenuItems
-                end
-                redrawMenu()
-            end
 
-        elseif param == keys.right then
+            elseif key == keys.right then
-            -- Right
-            if not bMenu then
                 local nLimit = #tLines[y] + 1
                 if x < nLimit then
                     -- Move cursor right
@@ -653,18 +616,8 @@ while bRunning do
                     -- Go to next line
                     setCursor(1, y + 1)
                 end
-            else
-                -- Move menu right
-                nMenuItem = nMenuItem + 1
-                if nMenuItem > #tMenuItems then
-                    nMenuItem = 1
-                end
-                redrawMenu()
-            end
 
-        elseif param == keys.delete then
+            elseif key == keys.delete and not bReadOnly then
-            -- Delete
-            if not bMenu and not bReadOnly then
                 local nLimit = #tLines[y] + 1
                 if x < nLimit then
                     local sLine = tLines[y]
@@ -677,11 +630,8 @@ while bRunning do
                     recomplete()
                     redrawText()
                 end
-            end
 
-        elseif param == keys.backspace then
+            elseif key == keys.backspace and not bReadOnly then
-            -- Backspace
-            if not bMenu and not bReadOnly then
                 if x > 1 then
                     -- Remove character
                     local sLine = tLines[y]
@@ -700,11 +650,8 @@ while bRunning do
                     setCursor(sPrevLen + 1, y - 1)
                     redrawText()
                 end
-            end
 
-        elseif param == keys.enter or param == keys.numPadEnter then
+            elseif (key == keys.enter or key == keys.numPadEnter) and not bReadOnly then
-            -- Enter/Numpad Enter
-            if not bMenu and not bReadOnly then
                 -- Newline
                 local sLine = tLines[y]
                 local _, spaces = string.find(sLine, "^[ ]+")
@@ -716,96 +663,56 @@ while bRunning do
                 setCursor(spaces + 1, y + 1)
                 redrawText()
 
-            elseif bMenu then
+            elseif key == keys.leftCtrl or key == keys.rightCtrl then
-                -- Menu selection
+                current_menu = menu.create(menu_items)
-                doMenuItem(nMenuItem)
-
-            end
-
-        elseif param == keys.leftCtrl or param == keys.rightCtrl then
-            -- Menu toggle
-            bMenu = not bMenu
-            if bMenu then
-                term.setCursorBlink(false)
-            else
-                term.setCursorBlink(true)
-            end
-            redrawMenu()
-        elseif param == keys.rightAlt then
-            if bMenu then
-                bMenu = false
-                term.setCursorBlink(true)
                 redrawMenu()
             end
         end
-
+    elseif event[1] == "char" then
-    elseif sEvent == "char" then
+        if current_menu then
-        if not bMenu and not bReadOnly then
+            handleMenuEvent(event)
+        elseif not bReadOnly then
             -- Input text
             local sLine = tLines[y]
-            tLines[y] = string.sub(sLine, 1, x - 1) .. param .. string.sub(sLine, x)
+            tLines[y] = string.sub(sLine, 1, x - 1) .. event[2] .. string.sub(sLine, x)
             setCursor(x + 1, y)
-
-        elseif bMenu then
-            -- Select menu items
-            for n, sMenuItem in ipairs(tMenuItems) do
-                if string.lower(string.sub(sMenuItem, 1, 1)) == string.lower(param) then
-                    doMenuItem(n)
-                    break
-                end
-            end
         end
 
-    elseif sEvent == "paste" then
+    elseif event[1] == "paste" and not bReadOnly then
-        if not bReadOnly then
         -- Close menu if open
-            if bMenu then
+        if current_menu then
-                bMenu = false
+            current_menu = nil
-                term.setCursorBlink(true)
             redrawMenu()
         end
-            -- Input text
-            local sLine = tLines[y]
-            tLines[y] = string.sub(sLine, 1, x - 1) .. param .. string.sub(sLine, x)
-            setCursor(x + #param, y)
-        end
 
-    elseif sEvent == "mouse_click" then
+        -- Input text
-        local cx, cy = param2, param3
+        local text = event[2]
-        if not bMenu then
+        local sLine = tLines[y]
-            if param == 1 then
+        tLines[y] = string.sub(sLine, 1, x - 1) .. text .. string.sub(sLine, x)
+        setCursor(x + #text, y)
+
+    elseif event[1] == "mouse_click" then
+        local button, cx, cy = event[2], event[3], event[4]
+        if current_menu then
+            handleMenuEvent(event)
+        else
+            if button == 1 then
                 -- Left click
                 if cy < h then
                     local newY = math.min(math.max(scrollY + cy, 1), #tLines)
                     local newX = math.min(math.max(scrollX + cx, 1), #tLines[newY] + 1)
                     setCursor(newX, newY)
                 else
-                    bMenu = true
+                    current_menu = menu.create(menu_items)
                     redrawMenu()
                 end
             end
-        else
-            if cy == h then
-                local nMenuPosEnd = 1
-                local nMenuPosStart = 1
-                for n, sMenuItem in ipairs(tMenuItems) do
-                    nMenuPosEnd = nMenuPosEnd + #sMenuItem + 1
-                    if cx > nMenuPosStart and cx < nMenuPosEnd then
-                        doMenuItem(n)
-                    end
-                    nMenuPosEnd = nMenuPosEnd + 1
-                    nMenuPosStart = nMenuPosEnd
-                end
-            else
-                bMenu = false
-                term.setCursorBlink(true)
-                redrawMenu()
-            end
         end
 
-    elseif sEvent == "mouse_scroll" then
+    elseif event[1] == "mouse_scroll" then
-        if not bMenu then
+        if not current_menu then
-            if param == -1 then
+            local direction = event[2]
+            if direction == -1 then
                 -- Scroll up
                 if scrollY > 0 then
                     -- Move cursor up
@@ -813,7 +720,7 @@ while bRunning do
                     redrawText()
                 end
 
-            elseif param == 1 then
+            elseif direction == 1 then
                 -- Scroll down
                 local nMaxScroll = #tLines - (h - 1)
                 if scrollY < nMaxScroll then
@@ -825,7 +732,7 @@ while bRunning do
             end
         end
 
-    elseif sEvent == "term_resize" then
+    elseif event[1] == "term_resize" then
         w, h = term.getSize()
         setCursor(x, y)
         redrawMenu()

projects/core/src/main/resources/data/computercraft/lua/rom/programs/fun/advanced/paint.lua

@@ -20,6 +20,7 @@ local canvasColour = colours.black
 local canvas = {}
 
 -- The menu options
+local menu = require "cc.internal.menu"
 local mChoices = { "Save", "Exit" }
 
 -- The message displayed in the footer bar
@@ -299,10 +300,7 @@ local menu_choices = {
         end
         return false
     end,
-    Exit = function()
+    Exit = function() return true end,
-        require "cc.internal.event".discard_char() -- Consume stray "char" events from pressing Ctrl then E separately.
-        return true
-    end,
 }
 
 --[[
@@ -310,80 +308,25 @@ local menu_choices = {
     returns: true if the program is to be exited; false otherwise
 ]]
 local function accessMenu()
-    -- Selected menu option
+    local current_menu = menu.create(mChoices)
-    local selection = 1
 
     term.setBackgroundColour(colours.black)
+    menu.draw(current_menu)
 
     while true do
-        -- Draw the menu
-        term.setCursorPos(1, h)
-        term.clearLine()
-        term.setTextColour(colours.white)
-        for k, v in pairs(mChoices) do
-            if selection == k then
-                term.setTextColour(colours.yellow)
-                term.write("[")
-                term.setTextColour(colours.white)
-                term.write(v)
-                term.setTextColour(colours.yellow)
-                term.write("]")
-                term.setTextColour(colours.white)
-            else
-                term.write(" " .. v .. " ")
-            end
-        end
-
         -- Handle input in the menu
-        local id, param1, param2, param3 = os.pullEvent()
+        local event = table.pack(os.pullEvent())
-        if id == "key" then
-            local key = param1
 
-            -- Handle menu shortcuts.
+        local result = menu.handle_event(current_menu, table.unpack(event, 1, event.n))
-            for _, menu_item in ipairs(mChoices) do
+        if result == false then
-                local k = keys[menu_item:sub(1, 1):lower()]
-                if k and k == key then
-                    return menu_choices[menu_item]()
-                end
-            end
-
-            if key == keys.right then
-                -- Move right
-                selection = selection + 1
-                if selection > #mChoices then
-                    selection = 1
-                end
-
-            elseif key == keys.left and selection > 1 then
-                -- Move left
-                selection = selection - 1
-                if selection < 1 then
-                    selection = #mChoices
-                end
-
-            elseif key == keys.enter or key == keys.numPadEnter then
-                -- Select an option
-                return menu_choices[mChoices[selection]]()
-            elseif key == keys.leftCtrl or keys == keys.rightCtrl then
-                -- Cancel the menu
             return false
+        elseif result ~= nil then
+            return menu_choices[result]()
         end
-        elseif id == "mouse_click" then
-            local cx, cy = param2, param3
-            if cy ~= h then return false end -- Exit the menu
 
-            local nMenuPosEnd = 1
+        if event[1] == "term_resize" then
-            local nMenuPosStart = 1
-            for _, sMenuItem in ipairs(mChoices) do
-                nMenuPosEnd = nMenuPosEnd + #sMenuItem + 1
-                if cx > nMenuPosStart and cx < nMenuPosEnd then
-                    return menu_choices[sMenuItem]()
-                end
-                nMenuPosEnd = nMenuPosEnd + 1
-                nMenuPosStart = nMenuPosEnd
-            end
-        elseif id == "term_resize" then
             termResize()
+            menu.draw(current_menu)
         end
     end
 end