Merge pull request #190 from TechHog8984/master

Fix an issue with vararg being indexed and add partial support for Luau if/else expressions.

Author: levno-710

src/prometheus/ast.lua

@@ -76,6 +76,8 @@ local AstKind = {
 
 	-- Misc
 	NopStatement = "NopStatement";
+
+	IfElseExpression = "IfElseExpression";
 }
 
 local astKindExpressionLookup = {
@@ -144,6 +146,15 @@ function Ast.NopStatement()
 	}
 end
 
+function Ast.IfElseExpression(condition, true_value, false_value)
+	return {
+		kind = AstKind.IfElseExpression,
+		condition = condition,
+		true_value = true_value,
+		false_value = false_value
+	}
+end
+
 -- Create Ast Top Node
 function Ast.TopNode(body, globalScope)
 	return {
@@ -789,4 +800,4 @@ end
 
 
 
-return Ast;
+return Ast;

src/prometheus/parser.lua

@@ -928,6 +928,19 @@ function Parser:expressionLiteral(scope)
 		local scope, id = scope:resolve(name);
 		return Ast.VariableExpression(scope, id);
 	end
+
+	-- IfElse
+	if(LuaVersion.LuaU) then
+		if(consume(self, TokenKind.Keyword, "if")) then
+			local condition = self:expression(scope);
+			expect(self, TokenKind.Keyword, "then");
+			local true_value = self:expression(scope);
+			expect(self, TokenKind.Keyword, "else");
+			local false_value = self:expression(scope);
+
+			return Ast.IfElseExpression(condition, true_value, false_value);
+		end
+	end
 
 	if(self.disableLog) then error() end
 	logger:error(generateError(self, "Unexpected Token \"" .. peek(self).source .. "\". Expected a Expression!"))
@@ -966,4 +979,4 @@ function Parser:tableConstructor(scope)
 	return Ast.TableConstructorExpression(entries);
 end
 
-return Parser
+return Parser

src/prometheus/unparser.lua

@@ -738,7 +738,7 @@ function Unparser:unparseExpression(expression, tabbing)
 	k = AstKind.IndexExpression;
 	if(expression.kind == k or expression.kind == AstKind.AssignmentIndexing) then
 		local base = self:unparseExpression(expression.base, tabbing);
-		if(Ast.astKindExpressionToNumber(expression.base.kind) > Ast.astKindExpressionToNumber(k)) then
+		if(expression.base.kind == AstKind.VarargExpression or Ast.astKindExpressionToNumber(expression.base.kind) > Ast.astKindExpressionToNumber(k)) then
 			base = "(" .. base .. ")";
 		end
 
@@ -860,6 +860,21 @@ function Unparser:unparseExpression(expression, tabbing)
 		return code .. self:optionalWhitespace((p and "," or "") .. self:newline() .. self:tabs(tabbing)) .. "}";
 	end
 
+	if (self.luaVersion == LuaVersion.LuaU) then
+		k = AstKind.IfElseExpression
+		if(expression.kind == k) then
+			code = "if ";
+
+			code = code .. self:unparseExpression(expression.condition);
+			code = code .. " then ";
+			code = code .. self:unparseExpression(expression.true_value);
+			code = code .. " else ";
+			code = code .. self:unparseExpression(expression.false_value);
+
+			return code
+		end
+	end
+
 	logger:error(string.format("\"%s\" is not a valid unparseable expression", expression.kind));
 end
 

src/prometheus/visitast.lua

@@ -235,11 +235,16 @@ function visitExpression(expression, previsit, postvisit, data)
 		expression.base = visitExpression(expression.base, previsit, postvisit, data);
 		expression.index = visitExpression(expression.index, 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);
+	end
 
 	if(type(postvisit) == "function") then
 		expression = postvisit(expression, data) or expression;
 	end
 	return expression;
 end
 
-return visitAst;
+return visitAst;