actually regenerate parser

more_math/Parser/MathExpr.g4

@@ -202,7 +202,8 @@ func3:
 	| SINE_EASE LPAREN expr COMMA expr COMMA expr RPAREN	# SineEaseFunc
 	| SMOOTHERSTEP LPAREN expr COMMA expr COMMA expr RPAREN	# SmootherstepFunc
 	| CROP LPAREN expr COMMA expr COMMA expr RPAREN	# CropFunc
-	| SIFFT LPAREN expr (COMMA expr)? RPAREN		# sifftFunc;
+	| SIFFT LPAREN expr (COMMA expr)? RPAREN		# sifftFunc
+	| OVERLAY LPAREN expr COMMA expr COMMA expr RPAREN	# OverlayFunc;
 func4:
 	SWAP LPAREN expr COMMA expr COMMA expr COMMA expr RPAREN	# SwapFunc
 	| NVL LPAREN expr COMMA expr COMMA expr COMMA expr RPAREN	# NvlFunc

more_math/Parser/MathExprVisitor.py

@@ -854,6 +854,11 @@ class MathExprVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
+    # Visit a parse tree produced by MathExprParser#OverlayFunc.
+    def visitOverlayFunc(self, ctx:MathExprParser.OverlayFuncContext):
+        return self.visitChildren(ctx)
+
+
     # Visit a parse tree produced by MathExprParser#SwapFunc.
     def visitSwapFunc(self, ctx:MathExprParser.SwapFuncContext):
         return self.visitChildren(ctx)