Matching REx `^s(?:(?:al)?|pre)ad$' against `sad' Setting an EVAL scope, savestack=6 0 <> | 1: BOL 0 <> | 2: EXACT 1 | 4: BRANCH Setting an EVAL scope, savestack=16 1 | 5: CURLYM[0] {0,1} 1 | 7: EXACT failed... matched 0 times, len=0... Setting an EVAL scope, savestack=16 trying tail with n=0... 1 | 15: EXACT 3 <> | 17: EOL 3 <> | 18: END Match successful! Guessing start of match, REx `^s(?:(?:al)?|pre)ad$' against `salad'... Found floating substr `ad'$ at offset 3... Found anchored substr `s' at offset 0... Guessed: match at offset 0 Matching REx `^s(?:(?:al)?|pre)ad$' against `salad' Setting an EVAL scope, savestack=6 0 <> | 1: BOL 0 <> | 2: EXACT 1 | 4: BRANCH Setting an EVAL scope, savestack=16 1 | 5: CURLYM[0] {0,1} 1 | 7: EXACT 3 | 9: SUCCEED could match... matched 1 times, len=2... Setting an EVAL scope, savestack=16 trying tail with n=1... 3 | 15: EXACT 5 <> | 17: EOL 5 <> | 18: END Match successful! Freeing REx: `"^s(?:(?:al)?|pre)ad$"'