This question处理传递给Ruby块的可选参数。我想知道是否也可以用默认值定义参数,以及它的语法是什么。
乍一看,答案似乎是“不”:
def call_it &block
block.call
end
call_it do |x = "foo"|
p "Called the block with value #{x}"
end
...results in:
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
^
https://stackoverflow.com/questions/1735657
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