Over here I said: " I suppose one could implement .t for patterns by pulling all the stream values from the right operand into an array before doing the operation. That would hang the interpreter if the right-hand operand is infinite-length however – which is common for patterns, hence risky."
.t at least is conceptually not outrageous, but IMO too dangerous. Even I made the mistake of putting an infinite pattern to the right of +.x – which in that case meant only that the left pattern would draw one value only. For +.t, the same mistake would be fatal.
Also patternA + patternB.clump(n) would do something like .t, but without the risk… coming back around to Daniel’s point (that adverbs may be less useful than they initially seem).
hjh