Try out replace and omit-tag

replace

replaced text = should be replaced
+: 1 1 = 2 = should be replaced
pre ( +: 1 1 ) post = pre ( 2 ) post = pre ( should be replaced ) post

omit-tag

Not using omit-tag (should not omit)
Void omit-tag (should omit)
'true' literal (should omit)
gt: 1 0 (should omit)
not: lt: 1 0 (should omit)
1 (should omit)
Children: 1 2 3
'false' literal (should not omit)
lt: 1 0 (should not omit)
not: gt: 1 0 (should not omit)
1 (should not omit)
Children: 1 2 3