Add a scale subcommand to monitor.lua (#623)

src/main/resources/data/computercraft/lua/rom/programs/monitor.lua

@@ -1,6 +1,8 @@
 local function printUsage()
     local programName = arg[0] or fs.getName(shell.getRunningProgram())
-    print("Usage: " .. programName .. " <name> <program> <arguments>")
+    print("Usage:")
+    print("  " .. programName .. " <name> <program> <arguments>")
+    print("  " .. programName .. " scale <name> <scale>")
     return
 end
 
@@ -10,6 +12,23 @@ if #tArgs < 2 then
     return
 end
 
+if tArgs[1] == "scale" then
+    local sName = tArgs[2]
+    if peripheral.getType(sName) ~= "monitor" then
+        print("No monitor named " .. sName)
+        return
+    end
+
+    local nRes = tonumber(tArgs[3])
+    if nRes == nil or nRes < 0.5 or nRes > 5 then
+        print("Invalid scale: " .. nRes)
+        return
+    end
+
+    peripheral.call(sName, "setTextScale", nRes)
+    return
+end
+
 local sName = tArgs[1]
 if peripheral.getType(sName) ~= "monitor" then
     print("No monitor named " .. sName)

src/main/resources/data/computercraft/lua/rom/startup.lua

@@ -67,10 +67,25 @@ shell.setCompletionFunction("rom/programs/label.lua", completion.build(
 ))
 shell.setCompletionFunction("rom/programs/list.lua", completion.build(completion.dir))
 shell.setCompletionFunction("rom/programs/mkdir.lua", completion.build({ completion.dir, many = true }))
+
+local complete_monitor_extra = { "scale" }
 shell.setCompletionFunction("rom/programs/monitor.lua", completion.build(
-    { completion.peripheral, true },
+    function(shell, text, previous)
-    completion.program
+        local choices = completion.peripheral(shell, text, previous, true)
+        for _, option in pairs(completion.choice(shell, text, previous, complete_monitor_extra, true)) do
+            choices[#choices + 1] = option
+        end
+        return choices
+    end,
+    function(shell, text, previous)
+        if previous[2] == "scale" then
+            return completion.peripheral(shell, text, previous, true)
+        else
+            return completion.program(shell, text, previous)
+        end
+    end
 ))
+
 shell.setCompletionFunction("rom/programs/move.lua", completion.build(
     { completion.dirOrFile, true },
     completion.dirOrFile

src/test/resources/test-rom/spec/programs/monitor_spec.lua

@@ -3,6 +3,22 @@ local capture = require "test_helpers".capture_program
 describe("The monitor program", function()
     it("displays its usage when given no arguments", function()
         expect(capture(stub, "monitor"))
-            :matches { ok = true, output = "Usage: monitor <name> <program> <arguments>\n", error = "" }
+            :matches {
+                ok = true,
+                output =
+                    "Usage:\n" ..
+                    "  monitor <name> <program> <arguments>\n" ..
+                    "  monitor scale <name> <scale>\n",
+                error = "",
+            }
+    end)
+
+    it("changes the text scale with the scale command", function()
+        local r = 1
+        stub(peripheral, "call", function(s, f, t) r = t end)
+        stub(peripheral, "getType", function() return "monitor" end)
+        expect(capture(stub, "monitor", "scale", "left", "0.5"))
+            :matches { ok = true, output = "", error = "" }
+        expect(r):equals(0.5)
     end)
 end)