October 8th Monday (十月 八日 月曜日）

 A syntax-case expression first evaluates <expression>.  It then attempts to match thepattern from
the first syntax-case clause against the resulting value, which is unwrapped as necessary to perform
the match.  If the pattern matches the value and no fender is present, <output expression> is evaluated
and its value returned as the value of the syntax-case expression. If the pattern does not match the
value, syntax-case tries the second <syntax-case clause>, then the third, and so on. It is a syntax
violation if the value does not match any of the pattern.

  If the optional <fender> is present, it serves as an additional constraint on acceptance of a clause.
If the <pattern> of a given <syntax-case clause> matches the input value, the corresponding <fender> is evaluated.  If <fender> evaluates to a true value, the clause is accepted;  otherwise, the clause is
rejected as if the pattern had failed to match the value.  Fenders are logically a part of the matching
process, i.e., they specify additional matching constraints beyond the basic structure of the input.