User blog comment:Hyp cos/R function II/@comment-2033667-20150408182105/@comment-11227630-20150408230117


 * There're 3 kinds of things we scan - 0, non-0 numbers and braces not a separator. 

A separator is NOT what you scan!

Scan nR{0+1}0 and you get the latter 0, and case A1 applies.