Module:Step vis

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Note: Do not invoke this module directly; use the corresponding template instead: Template:Step vis.

This module depends on the following other modules: Module: Template input parse Module: Yesno

Generates a visual representation of a scale based on predefined step sizes.

---

local tip = require("Module:Template input parse")
local yesno = require("Module:Yesno")
local p = {}

-- Helper function
-- Create a step visualization that's based on the table on the diasem page
function p.step_pattern_to_visualization(step_pattern)
	local step_pattern = step_pattern or { 5, 2, 5, 0, 5, 2, 0 }
	
	local left_border = "├"              -- U+251C ├
	local right_border = "┤"	            -- U+2524 ┤
	local no_border = "─"                -- U+2500 ─
	local double_border = "╫"            -- U+256B ╫
	local double_border_left = "╟"       -- U+255F ╟
	local double_border_right = "╢"      -- U+2562 ╢
	local single_border = "┼"            -- U+253C ┼
	
	local step_visualization = ""
	local previous_step_size = 0
	
	--[[
	 - For each step size of k, print a single border, followed by k-1 no-border symbols
	 - If this is the first step, print the left border instead
	 - If the step size is 0, print a double border only; if this happens, the next step should start with a border character
	 - If this is the last step, add a right border after the entire sequence
	]]--
	for i = 1, #step_pattern do
		local current_step_vis = ""
		local current_step_size = step_pattern[i]
		
		if i == 1 then
			-- Start of string
			current_step_vis = (current_step_size == 0 and double_border_left or left_border .. string.rep(no_border, current_step_size - 1))
		elseif i == #step_pattern then
			-- End of string
			if current_step_size == 0 then
				-- If the last step size is 0, the last character will be a double right border
				if (previous_step_size == 0) then
					--[[
					 - The beginning of a string is index 1 in the first argument of string.sub
					 - The end of the string is index -1 in the second argument of string.sub, and an ampersand version
					   of a 4-digit code point is 8 characters long, so removing the last box-drawing character means
					   removing the last 8 characters representing it, between indices -1 and -9
					 - This removes the double centre border at the end if the second-to-last and last steps are both 0
					 - In debugging mode, the HTML entities themselves are displayed, so the index is -13 instead of -9
					]]--
					step_visualization = string.sub(step_visualization, 1, -9)
				end
				current_step_vis = double_border_right
			else
				-- If the last step size is not 0, add a single border, then add the horizontal bar and right border
				if previous_step_size ~= 0 then
					current_step_vis = current_step_vis .. single_border
				end
				current_step_vis = current_step_vis .. string.rep(no_border, current_step_size - 1) .. right_border
			end
		else
			-- Steps in between
			if current_step_size == 0 and previous_step_size ~= 0 then
				-- Zero-size steps that are not first or last
				current_step_vis = double_border
			else
				-- Other non-zero step sizes
				if step_pattern[i - 1] ~= 0 then
					current_step_vis = current_step_vis .. single_border
				end
				current_step_vis = current_step_vis .. string.rep(no_border, current_step_size - 1)
			end
		end
		
		step_visualization = step_visualization .. current_step_vis
		previous_step_size = current_step_size
	end
	
	return step_visualization
end

-- Wrapper function for step visualization
function p.step_vis_frame(frame)
	local step_pattern = tip.parse_numeric_entries(frame.args["Step Pattern"], " ")
	local debugg = yesno(frame.args["debug"])
	local result = p.step_pattern_to_visualization(step_pattern)
	
	-- Debugger option
	if debugg == true then
		result = "<syntaxhighlight lang=\"wikitext\">" .. result .. "</syntaxhighlight>"
	end
	
	return frame:preprocess(result)
end

return p