Java – only remove system. Java from the for loops block Out statement

Any method can only easily delete them from the for loop blocks in the file

Before:

for( ... ) {
...
System.out.println("string");
...
System.out.println("string");
...
}

After:

for( ... ) {
...
... 
...
}

Solution

This is tricky: which closing bracket closes for loop? Either parse the entire code or use some heuristics In the following solution, I require that the intention of the right parenthesis is the same as that of the for keyword:

$perl -nE'
    if( /^(\s*)for\b/ .. /^$ws\}/ ) {
      $ws = $1 // $ws;
      /^\s*System\.out\.println/ or print;
    } else { print }'

This uses the trigger operator cond1 COND2. This script can be used as a simple filter

$perl -nE'...' <source >processed

Or backup function:

$perl -i.bak -nE'...' source

(create the file source.bak as a backup)

Test only for example inputs; Not a sensible test suite The script passed the gles prateek Nina test

To run this script on all java files in the directory

$perl -i.bak -nE'...' *.java

edit

On Windows systems, the delimiter must be changed to ". In addition, we must perform global operations ourselves

> perl -nE"if(/^(\s*)for\b/../^$ws\}/){$ws=$1//$ws;/^\s*System\.out\.println/ or print}else{print}BEGIN{@ARGV=$#ARGV?@ARGV:glob$ARGV[0]}" *.java

Edit 2

This is the implementation of the bracket counting algorithm outlined in my review This solution can also be backed up Command line arguments are interpreted as glob expressions

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

clean($_) for map glob($_),@ARGV;

sub clean {
    local @ARGV = @_;
    local $^I = ".bak";
    my $depth = 0;
    while (<>) {
        $depth ||= /^\s*for\b/ ? "0 but true" : 0;
        my $delta = ( ()= /\{/g ) - ( ()= /\}/g );
        $depth += $delta if $depth && $delta;
        $depth = 0 if $depth < 0;
        print unless $depth && /^\s*System\.out\.println/;
    }
    return !!1;
}

There is no comment This will only re identify the system that started the new line out. Println statement

Usage example: > Perl thisscript pl * . java.

This is a test file with pseudo Java syntax. I use it to test Once the script runs, all lines marked XXX will disappear

/** Java test suite **/

bare block {
    System.out.println(...); // 1 -- let stand
}

if (true) {
    for (foo in bar) {
        System.out.println; // 2 XXX
        if (x == y) {
            // plz kill this
            System.out.println // 3 XXX
        } // don't exit here
        System.out.println // 4 XXX
    }
}

for (...) {
    for {
        // will this be removed?
        System.out.println // 5 XXX
    }
}

/* pathological cases */

// intendation
for (...) { System.out.println()/* 6 */} 

// intendation 2
for (...)
{
    if (x)
    {
        System.out.println // 7 XXX
    }}

// inline weirdness
for (...) {
    // "confuse" script here
    foo = new baz() {void qux () {...}
    };
    System.out.println // 8 XXX
}

No. 1 should stay, and it is Declaration № 6 shall be deleted; But these scripts can't do that