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Specification of executing order of multiple scope(s)
May 31, 2023
An Pham
Jun 01, 2023
vit
Jun 02, 2023
bauss
May 31, 2023
Gravatar of An PhamPosted by An PhamReply
An Pham
Gravatar of An Pham


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Should the scope failure to be executed before exit regardless of the code order?

import std.exception, std.stdio;

void test()
{
    writeln("test");

    scope (failure)
    {
    	writeln("failure");
    }

    scope (exit)
    {
        writeln("exit");
    }

    throw new Exception("exception");
}

void main()
{
    try
    {
        test();
    }
    catch (Exception e) writeln(e.msg);
}

Output
test
exit
failure
exception

June 01, 2023
Gravatar of vitPosted by vit
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vit
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Posted in reply to An Pham


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On Wednesday, 31 May 2023 at 15:52:08 UTC, An Pham wrote:

>

Should the scope failure to be executed before exit regardless of the code order?

import std.exception, std.stdio;

void test()
{
    writeln("test");

    scope (failure)
    {
    	writeln("failure");
    }

    scope (exit)
    {
        writeln("exit");
    }

    throw new Exception("exception");
}

void main()
{
    try
    {
        test();
    }
    catch (Exception e) writeln(e.msg);
}

Output
test
exit
failure
exception

No, scopes are rewritten with compiler to something like this:


	void test()
	{
		writeln("test");

		try{
		
			try{
				throw new Exception("exception");
			
			}
			finally{
				writeln("exit");
			}
		}
		catch(Exception ex){
			writeln("failure");
			throw ex;
		}
	}
	void main()
	{
		try
		{
			test();
		}
		catch (Exception e) writeln(e.msg);
	}
June 01, 2023
Gravatar of Steven SchveighofferPosted by Steven Schveighoffer
in reply to An Pham		Reply
Steven Schveighoffer
Gravatar of Steven Schveighoffer
Posted in reply to An Pham


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On 5/31/23 11:52 AM, An Pham wrote:

>

Should the scope failure to be executed before exit regardless of the code order?

import std.exception, std.stdio;

    void test()
    {
        writeln("test");

        scope (failure)
        {
            writeln("failure");
        }

        scope (exit)
        {
            writeln("exit");
        }

        throw new Exception("exception");
    }

    void main()
    {
        try
        {
            test();
        }
        catch (Exception e) writeln(e.msg);
    }

Output
test
exit
failure
exception

From the D spec:

If there are multiple ScopeGuardStatements in a scope, they will be executed in the reverse lexical order in which they appear.

-Steve

June 02, 2023
Gravatar of baussPosted by bauss
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bauss
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Posted in reply to An Pham


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On Wednesday, 31 May 2023 at 15:52:08 UTC, An Pham wrote:

>

Should the scope failure to be executed before exit regardless of the code order?

import std.exception, std.stdio;

void test()
{
    writeln("test");

    scope (failure)
    {
    	writeln("failure");
    }

    scope (exit)
    {
        writeln("exit");
    }

    throw new Exception("exception");
}

void main()
{
    try
    {
        test();
    }
    catch (Exception e) writeln(e.msg);
}

Output
test
exit
failure
exception

Just move the exit scope guard before failure and it will do what you want.