View Compilation Error

0_0_17021142_759.cpp:1:1: error: 'P' does not name a type
 P is    if next is a unary operator         const op := unary(next)         consume         q := prec( op )         const t := Exp( q )         return mkNode( op, t )    else if next = "("         consume         const t := Exp( 0 )         expect ")"         return t    else if next is a v         const t := mkLeaf( next )         consume         return t    else         error
 ^