嵌套块和 ERB

Question

对于我的一生，我无法弄清楚为什么这不能按预期工作。

代码：

require 'erb'

def say_hello(name)
  "Nice to see you, #{ name }!"
end

def greetings
  template = <<-TEMPLATE
Hello!
<%= yield %>
Goodbye!
  TEMPLATE
  ERB.new(template).result(binding)
end

people = ['Aaron', 'Bob', 'Tim', 'Juan']
t = greetings do
  people.each do |p|
    say_hello(p)
  end
end

puts t

（有点做作，我知道，但它会起到作用。）

我的期望：

Hello!
Nice to see you, Aaron!
Nice to see you, Bob!
Nice to see you, Tim!
Nice to see you, Juan!
Goodbye!

我得到了什么：

Hello!
['Aaron', 'Bob', 'Tim', 'Juan']
Goodbye!

想法：

我猜这是因为内部块（以people.each 开头）在块执行之前被强制转换为字符串。也许 ERB 不喜欢我尝试将新的构造文本块注入其模板的方式。

这是怎么回事？

Answer 1

each的返回值是数组本身，而不是块的返回值：

people.each do |p|
  say_hello(p)
end
# => ['Aaron', 'Bob', 'Tim', 'Juan']

你应该使用map，它从块中返回返回值的数组：

people.map do |p|
  say_hello(p)
end
# => ["Nice to see you, Aaron!", "Nice to see you, Bob!", "Nice to see you, Tim!", "Nice to see you, Juan!"]

您还需要连接数组以正确呈现它：

t = greetings do
  people.map do |p|
    say_hello(p)
  end.join("\n")
end