Code before warnings are enabled at line 7, column 1.  See page 431 of PBP.  (Severity: 4)
Don't modify $_ in list functions at line 375, column 14.  See page 114 of PBP.  (Severity: 5)
Don't modify $_ in list functions at line 376, column 15.  See page 114 of PBP.  (Severity: 5)
Comma used to separate statements at line 380, column 19.  See pages 68,71 of PBP.  (Severity: 4)