Added example showing dual code using "!!".

Author: ReFreezed

examples/dualCode.lua2p

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+--[[============================================================
+--=
+--=  LuaPreprocess example: Dual code.
+--=
+--=  Here we have some constants that are used in both the
+--=  metaprogram and in the final program.
+--=
+--============================================================]]
+
+-- Assignments starting with !! will appear in both the metaprogram and the final output.
+!!local TEXT_HEIGHT    = 30
+
+!!local BUTTON_PADDING = 15
+!!local BUTTON_BORDER  = 2
+
+!!local BUTTON_WIDTH   = 400
+!!local BUTTON_HEIGHT  = TEXT_HEIGHT + 2*BUTTON_PADDING + 2*BUTTON_BORDER
+
+!(
+local function getImageWidth(imagePath)
+	return 100 -- Dummy value.
+end
+)
+
+function drawImage(imagePath, x, y, scale)    print("Drawing image with scale "..scale)  end
+function drawBackground(x, y, width, height)  print("Drawing background")                end
+function drawBorder(x, y, width, height)      print("Drawing border")                    end
+function drawLabel(x, y, label)               print("Drawing label: "..label)            end
+
+function drawButton(label, x, y)
+	!local scale = getImageWidth("button_background.png") / BUTTON_WIDTH
+
+	drawImage("button_background.png", x, y, !(scale))
+
+	drawBorder(x, y, BUTTON_WIDTH, BUTTON_HEIGHT)
+	drawLabel(x, y, label)
+end
+
+function drawContextMenu(x, y, menuItemLabels)
+	local menuWidth  = BUTTON_WIDTH
+	local menuHeight = #menuItemLabels * BUTTON_HEIGHT
+
+	drawBackground(x, y, menuWidth, menuHeight)
+
+	for i, label in ipairs(menuItemLabels) do
+		drawButton(label, x, y)
+		y = y+BUTTON_HEIGHT
+	end
+end
+
+drawContextMenu(20, 50, {"Copy","Cut","Paste"})

examples/dualCode.output.lua

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+--[[============================================================
+--=
+--=  LuaPreprocess example: Dual code.
+--=
+--=  Here we have some constants that are used in both the
+--=  metaprogram and in the final program.
+--=
+--============================================================]]
+
+-- Assignments starting with !! will appear in both the metaprogram and the final output.
+local TEXT_HEIGHT    = 30
+local BUTTON_PADDING = 15
+local BUTTON_BORDER  = 2
+local BUTTON_WIDTH   = 400
+local BUTTON_HEIGHT  = 64
+
+function drawImage(imagePath, x, y, scale)    print("Drawing image with scale "..scale)  end
+function drawBackground(x, y, width, height)  print("Drawing background")                end
+function drawBorder(x, y, width, height)      print("Drawing border")                    end
+function drawLabel(x, y, label)               print("Drawing label: "..label)            end
+
+function drawButton(label, x, y)
+	drawImage("button_background.png", x, y, 0.25)
+
+	drawBorder(x, y, BUTTON_WIDTH, BUTTON_HEIGHT)
+	drawLabel(x, y, label)
+end
+
+function drawContextMenu(x, y, menuItemLabels)
+	local menuWidth  = BUTTON_WIDTH
+	local menuHeight = #menuItemLabels * BUTTON_HEIGHT
+
+	drawBackground(x, y, menuWidth, menuHeight)
+
+	for i, label in ipairs(menuItemLabels) do
+		drawButton(label, x, y)
+		y = y+BUTTON_HEIGHT
+	end
+end
+
+drawContextMenu(20, 50, {"Copy","Cut","Paste"})