From 31a4d89a4960a1367428d74f89e4eccd72cc1ba1 Mon Sep 17 00:00:00 2001
From: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>
Date: Wed, 28 Jul 2021 17:39:09 +0100
Subject: [PATCH] TEST: implement split_shell

---
 .../utils/strings/split_shell.lua             | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 worldeditadditions/utils/strings/split_shell.lua

diff --git a/worldeditadditions/utils/strings/split_shell.lua b/worldeditadditions/utils/strings/split_shell.lua
new file mode 100644
index 0000000..6b8b2ba
--- /dev/null
+++ b/worldeditadditions/utils/strings/split_shell.lua
@@ -0,0 +1,72 @@
+function is_whitespace(char)
+	return char == " " or char == "\t" or char == "\r" or char == "\n"
+end
+
+function split_shell(text)
+	local text_length = #text
+	local scan_pos = 1
+	local result = {  }
+	local acc = {}
+	local mode = "NORMAL"	-- NORMAL, INSIDE_QUOTES_SINGLE, INSIDE_QUOTES_DOUBLE
+	
+	
+	for i=1,text_length do
+		local prevchar = ""
+		local curchar = text:sub(i,i)
+		local nextchar = ""
+		local nextnextchar = ""
+		if i > 1 then prevchar = text:sub(i-1, i-1) end
+		if i < text_length then nextchar = text:sub(i+1, i+1) end
+		if i+1 < text_length then nextnextchar = text:sub(i+2, i+2) end
+		
+		if mode == "NORMAL" then
+			if is_whitespace(curchar) and #acc > 0 then
+				table.insert(result, table.concat(acc, ""))
+				acc = {}
+			elseif (curchar == "\"" or curchar == "'") and #acc == 0 and prevchar ~= "\\" then
+				if curchar == "\"" then
+					mode = "INSIDE_QUOTES_DOUBLE"
+				else
+					mode = "INSIDE_QUOTES_SINGLE"
+				end
+			else
+				table.insert(acc, curchar)
+			end
+		elseif mode == "INSIDE_QUOTES_DOUBLE" then
+			if curchar == "\"" and prevchar ~= "\\" and is_whitespace(nextchar) then
+				-- It's the end of a quote!
+				mode = "NORMAL"
+			elseif (curchar == "\\" and nextchar ~= "\"" and not is_whitespace(nextnextchar)) or curchar ~= "\\" then
+				-- It's a regular character
+				table.insert(acc, curchar)
+			end
+		elseif mode == "INSIDE_QUOTES_SINGLE" then
+			if curchar == "'" and prevchar ~= "\\" and is_whitespace(nextchar) then
+				-- It's the end of a quote!
+				mode = "NORMAL"
+			elseif (curchar == "\\" and nextchar ~= "'" and not is_whitespace(nextnextchar)) or curchar ~= "\\" then
+				-- It's a regular character
+				table.insert(acc, curchar)
+			end
+		end
+	end
+	
+	if #acc > 0 then
+		table.insert(result, table.concat(acc, ""))
+	end
+	return result
+end
+
+function test(text)
+	print("Source", text)
+	for i,value in ipairs(split_shell(text)) do
+		print("i", i, "→", value)
+	end
+	print("************")
+end
+
+test("yay yay yay")
+test("yay \"yay yay\" yay")
+test("yay \"yay\\\" yay\" yay")
+test("yay \"yay 'inside quotes' yay\" yay")
+test("yay 'inside quotes' another")