51.4.2 sicstus Execution Mode Rules

quoted-name ::= quoted-atom

base-prefix ::= base ' {indicates base base }

base ::= digit... { in the range [2..36] }

char-item ::= char { other than `\' }
| \ escape-sequence { unless character escapes have been switched off }

other-escape-sequence ::= x alpha alpha {treating a,b,... and A,B,... as 10,11,... in the range [0..15], hex character code }
| digit ?digit ?digit { in the range [0..7], octal character code }
| ^ ?{ delete, character code 127 }
| ^ alpha { where alpha must be a letter, stands for the control character alpha mod 32 }
| c ?layout-char...{ ignored }
| layout-char { ignored }
| char { other than the above, stands for itself }

quoted-char ::= layout-char
| printing-char