perl 中的控制流验证 [英] control flow validation in perl

问题描述

这是我的代码，它有 switch 语句工作正常，但如果用户输入大于 3 或空白文本，那么它应该留在第一个子例程中我如何在 perl 中执行此操作

This is my code which has switch statement works fine but if user enters greater than 3 or blank text then it should stay in first sub routine how can i do this in perl

use strict;
use warnings;
use Switch;

my $input = "Enter the number:";


sub input(){
    print "Choose You Input Method"."\n";
    print "1.UPC"."\n";
    print "2.URL"."\n";
    print "3.Elastic Search"."\n";
    print $input;
    $input = <>;
    chomp($input);
    switch($input){
        case 1 {print "UPC"."\n"}
        case 2 {print "URL"."\n"}
        case 3 {print "Elastic Search"."\n"}
        else {print "Enter the correct value"."\n"}

}
}

input();

my $pinput = "Enter the number:";
sub pinput(){
    print "Choose Your Process Method"."\n";
    print "1.API"."\n";
    print "2.Mongo"."\n";
    print $pinput;
    $pinput = <>;
    chomp($pinput);
    switch($pinput){
       case 1 {print "API"."\n"}
       case 2 {print "MONGO"."\n"}
       else {print "Enter the correct value"."\n"}
}
}

pinput();

如果用户输入诸如 4 或空白数据之类的内容，则不应将其传递给另一个子例程，而应保留在同一个子例程中，我该怎么做?

if user enters something like 4 or blank data it should not pass to another sub routine it should stay on the same sub routine how can i do this?

推荐答案

用redo将提示代码包裹成块:

Wrap the prompt code into a block with redo:

#!/usr/bin/perl
use warnings;
use strict;

use Switch::Plain;

PROMPT: {
    chomp(my $input = <>);
     nswitch ($input) {
         case 1  : { print "UPC\n" }
         case 2  : { print "URL\n" }
         case 3  : { print "Elastic Search\n" }
         default : { print "Enter the correct value\n" ; redo PROMPT }
     }
}

我使用了 Switch::Plain 而不是 Switch，因为它更安全(它不使用源过滤器)并且足以满足您的需求.

I used Switch::Plain instead of Switch, as it is much safer (it doesn't use a source filter) and sufficient for your case.

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