Enhance expressionPow to support unary operators on the right-hand side, preserving right-associativity. Added tests to validate the fix for precedence issues.

Author: SpinnySpiwal

src/prometheus/parser.lua

@@ -716,7 +716,8 @@ function Parser:expressionPow(scope)
 	local lhs = self:tableOrFunctionLiteral(scope);
 
 	if(consume(self, TokenKind.Symbol, "^")) then
-		local rhs = self:expressionPow(scope);
+		-- Allow unary operators on the rhs (e.g. 2 ^ #x, 2 ^ -x) while preserving right-associativity. ~ SpinnySpiwal
+		local rhs = self:expressionUnary(scope);
 		return Ast.PowExpression(lhs, rhs, true);
 	end
 

tests/syntax.lua

@@ -2,7 +2,8 @@
 -- Syntax Test Suite
 -- Target: Unparser
 -- Author: SpinnySpiwal
--- Purpose: Validate appropriate unparser functionality, specifically in unseen edge cases.
+-- Purpose: Validate appropriate parser & unparser functionality, specifically in unseen edge cases.
+-- Update 1: Added test for precedence bug fix in expressionPow.
 --============================================================
 
 local char = ("").char
@@ -17,3 +18,21 @@ local ok = pcall(function(...)
     print("hello " .. ...)
 end)
 print(ok and "no" or "yes")
+
+local function getString()
+	return "this string is 24 chars!"
+end
+
+-- Test for precedence bug fix in expressionPow
+if 2 ^ #getString() == 16777216 then
+	print("TEST 1 PASSED")
+else
+	print("TEST 1 FAILED")
+end
+
+-- Check if it still works the other way around
+if (#getString()) ^ 2 == 576 then
+	print("TEST 2 PASSED")
+else
+	print("TEST 2 FAILED")
+end