这个问题处理传递给 Ruby 块的可选参数。我想知道是否也可以使用默认值定义参数,以及它的语法是什么。
乍一看,答案似乎是“否”:
def call_it &block
block.call
end
call_it do |x = "foo"|
p "Called the block with value #{x}"
end
...结果是:
my_test.rb:5: syntax error, unexpected '=', expecting '|'
call_it do |x = "foo"|
^
my_test.rb:6: syntax error, unexpected tSTRING_BEG, expecting kDO or '{' or '('
p "Called the block with value #{x}"
^
my_test.rb:7: syntax error, unexpected kEND, expecting $end
end
^