Full support of LuaU's if else expression.

src/prometheus/ast.lua

@@ -148,11 +148,12 @@ function Ast.NopStatement()
 	}
 end
 
-function Ast.IfElseExpression(condition, true_value, false_value)
+function Ast.IfElseExpression(condition, true_value, elseifs, false_value)
 	return {
 		kind = AstKind.IfElseExpression,
 		condition = condition,
 		true_value = true_value,
+		elseifs = elseifs,
 		false_value = false_value
 	}
 end

src/prometheus/compiler/expressions.lua

@@ -28,6 +28,7 @@ handlers[AstKind.AndExpression] = requireExpression("and");
 handlers[AstKind.TableConstructorExpression] = requireExpression("table_constructor");
 handlers[AstKind.FunctionLiteralExpression] = requireExpression("function_literal");
 handlers[AstKind.VarargExpression] = requireExpression("vararg");
+handlers[AstKind.IfElseExpression] = requireExpression("if_else");
 
 -- Binary ops share one handler
 local binaryHandler = requireExpression("binary");

src/prometheus/compiler/expressions/if_else.lua

@@ -0,0 +1,80 @@
+-- This Script is Part of the Prometheus Obfuscator by levno-710
+--
+-- if_else.lua
+--
+-- This Script contains the statement handler for the IfElseExpression.
+
+local Ast = require("prometheus.ast");
+
+return function(self, expression, funcDepth, numReturns)
+	local scope = self.activeBlock.scope;
+	local posState = self.registers[self.POS_REGISTER];
+    self.registers[self.POS_REGISTER] = self.VAR_REGISTER;
+
+	local regs = {};
+	for i = 1, numReturns do
+		regs[i] = self:allocRegister();
+		if i ~= 1 then
+			self:addStatement(self:setRegister(scope, regs[i], Ast.NilExpression()), {regs[i]}, {}, false);
+		end
+	end
+
+	local resReg = regs[1];
+	local tmpReg;
+
+	if posState then
+        tmpReg = self:allocRegister(false);
+        self:addStatement(self:copyRegisters(scope, {tmpReg}, {self.POS_REGISTER}), {tmpReg}, {self.POS_REGISTER}, false);
+    end
+
+	local conditionReg = self:compileExpression(expression.condition, funcDepth, 1)[1];
+
+	local finalBlock = self:createBlock();
+	local nextBlock = self:createBlock();
+	local innerBlock = self:createBlock();
+
+	self:addStatement(self:setRegister(scope, self.POS_REGISTER, Ast.OrExpression(Ast.AndExpression(self:register(scope, conditionReg), Ast.NumberExpression(innerBlock.id)), Ast.NumberExpression(nextBlock.id))), {self.POS_REGISTER}, {conditionReg}, false);
+	self:freeRegister(conditionReg, false);
+
+	self:setActiveBlock(innerBlock);
+	scope = innerBlock.scope;
+
+	local trueReg = self:compileExpression(expression.true_value, funcDepth, 1)[1];
+	self:addStatement(self:copyRegisters(scope, {resReg}, {trueReg}), {resReg}, {trueReg}, false);
+	self:addStatement(self:setRegister(scope, self.POS_REGISTER, Ast.NumberExpression(finalBlock.id)), {self.POS_REGISTER}, {}, false);
+
+	for _, elif in ipairs(expression.elseifs) do
+		self:setActiveBlock(nextBlock);
+		conditionReg = self:compileExpression(elif.condition, funcDepth, 1)[1];
+		local elifBlock = self:createBlock();
+		nextBlock = self:createBlock();
+		local elifScope = self.activeBlock.scope;
+
+		self:addStatement(self:setRegister(elifScope, self.POS_REGISTER, Ast.OrExpression(Ast.AndExpression(self:register(elifScope, conditionReg), Ast.NumberExpression(elifBlock.id)), Ast.NumberExpression(nextBlock.id))), {self.POS_REGISTER}, {conditionReg}, false);
+		self:freeRegister(conditionReg, false);
+
+		self:setActiveBlock(elifBlock);
+		elifScope = elifBlock.scope;
+		local valueReg = self:compileExpression(elif.value, funcDepth, 1)[1];
+		self:addStatement(self:copyRegisters(elifScope, {resReg}, {valueReg}), {resReg}, {valueReg}, false);
+		self:addStatement(self:setRegister(elifScope, self.POS_REGISTER, Ast.NumberExpression(finalBlock.id)), {self.POS_REGISTER}, {}, false);
+	end
+
+	self:setActiveBlock(nextBlock);
+	scope = self.activeBlock.scope;
+	local falseReg = self:compileExpression(expression.false_value, funcDepth, 1)[1];
+	self:addStatement(self:copyRegisters(scope, {resReg}, {falseReg}), {resReg}, {falseReg}, false);
+	self:addStatement(self:setRegister(scope, self.POS_REGISTER, Ast.NumberExpression(finalBlock.id)), {self.POS_REGISTER}, {}, false);
+
+	self.registers[self.POS_REGISTER] = posState;
+
+	self:setActiveBlock(finalBlock);
+	scope = finalBlock.scope;
+
+    if tmpReg then
+        self:addStatement(self:copyRegisters(scope, {self.POS_REGISTER}, {tmpReg}), {self.POS_REGISTER}, {tmpReg}, false);
+        self:freeRegister(tmpReg, false);
+    end
+
+	return regs;
+end

src/prometheus/parser.lua

@@ -946,10 +946,23 @@ function Parser:expressionLiteral(scope)
 			local condition = self:expression(scope);
 			expect(self, TokenKind.Keyword, "then");
 			local true_value = self:expression(scope);
+
+			local elseifs = {}
+			while(consume(self, TokenKind.Keyword, "elseif")) do
+				local elseif_condition = self:expression(scope);
+				expect(self, TokenKind.Keyword, "then");
+				local elseif_value = self:expression(scope);
+
+				table.insert(elseifs, {
+					condition = elseif_condition,
+					value = elseif_value
+				});
+			end
+
 			expect(self, TokenKind.Keyword, "else");
 			local false_value = self:expression(scope);
 
-			return Ast.IfElseExpression(condition, true_value, false_value);
+			return Ast.IfElseExpression(condition, true_value, elseifs, false_value);
 		end
 	end
 

src/prometheus/unparser.lua

@@ -688,6 +688,12 @@ function Unparser:unparseExpression(expression, tabbing)
 			push(self:unparseExpression(expression.condition));
 			push(" then ");
 			push(self:unparseExpression(expression.true_value));
+			for _, elseifexp in pairs(expression.elseifs) do
+				push(" elseif ");
+				push(self:unparseExpression(elseifexp.condition));
+				push(" then ");
+				push(self:unparseExpression(elseifexp.value));
+			end
 			push(" else ");
 			push(self:unparseExpression(expression.false_value));
 			return joinParts(parts);

src/prometheus/visitast.lua

@@ -238,8 +238,12 @@ function visitExpression(expression, previsit, postvisit, data)
 	end
 	if(expression.kind == AstKind.IfElseExpression) then
 		expression.condition = visitExpression(expression.condition, previsit, postvisit, data);
-		expression.true_expr = visitExpression(expression.true_expr, previsit, postvisit, data);
-		expression.false_expr = visitExpression(expression.false_expr, previsit, postvisit, data);
+		expression.true_value = visitExpression(expression.true_value, previsit, postvisit, data);
+		for i, elif in pairs(expression.elseifs) do
+			elif.condition = visitExpression(elif.condition, previsit, postvisit, data);
+			elif.value = visitExpression(elif.value, previsit, postvisit, data);
+		end
+		expression.false_value = visitExpression(expression.false_value, previsit, postvisit, data);
 	end
 
 	if(type(postvisit) == "function") then