在 Ruby 的情况下使用带有正则表达式匹配的命名捕获......什么时候? [英] Using Named Captures with regex match in Ruby's case...when?
问题描述
为了便于阅读,我想使用命名捕获来解析用户输入.
I want to parse user input using named captures for readability.
当他们输入命令时,我想捕获一些参数并传递它们.我在 case 语句中使用 RegExps,因此无法分配 /pattern/.named_captures
的返回值.
When they type a command I want to capture some params and pass them. I'm using RegExps in a case statement and thus I can't assign the return of /pattern/.named_captures
.
这是我想做的事情(例如):
Here is what I would like to be able to do (for example):
while command != "quit"
print "Command: "
command = gets.chomp
case command
when /load (?<filename>w+)/
load(filename)
end
end
推荐答案
named captures设置局部变量时使用这种语法.
named captures set local variables when this syntax.
regex-literal =~ string
不使用其他语法设置.# 见 rdoc(re.c)
Dosen't set in other syntax. # See rdoc(re.c)
regex-variable =~ string
string =~ regex
regex.match(string)
case string
when regex
else
end
我也喜欢命名捕获,但我不喜欢这种行为.现在,我们必须在 case 语法中使用 $~.
I like named captures too, but I don't like this behavior. Now, we have to use $~ in case syntax.
case string
when /(?<name>.)/
$~[:name]
else
end
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