diff --git a/core/src/main/antlr4/MetricExpression.g4 b/core/src/main/antlr4/MetricExpression.g4
index 2c42a93416..1df365f180 100644
--- a/core/src/main/antlr4/MetricExpression.g4
+++ b/core/src/main/antlr4/MetricExpression.g4
@@ -34,6 +34,7 @@ logicalOperands : relationalExpression | TRUE | FALSE
            ;
 
 arthmeticExpression : '(' arthmeticExpression ')'                       #paren_arith_rule
+                    |  ABSOLUTE '('   arthmeticExpression ')'              #abs_rule
                     |  arthmeticExpression '%' arthmeticExpression      #mod_arith_rule
                     | arthmeticExpression ('/'|'*') arthmeticExpression #divmul_arith_rule
                     | arthmeticExpression ('-'|'+') arthmeticExpression #addsub_arith_rule
@@ -77,6 +78,8 @@ not : N O T | '!'
 TRUE : T R U E;
 FALSE: F A L S E;
 
+ABSOLUTE: A B S;
+
 modulo : '%' ;
 
 metric: REX;