www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 4656] New: stdio.readf does not ignore white space

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4656

           Summary: stdio.readf does not ignore white space
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: acehreli yahoo.com


--- Comment #0 from Ali Cehreli <acehreli yahoo.com> 2010-08-16 14:11:35 PDT ---
This makes it very difficult to read values. We can't retire din.readf before
fixing this.

import std.stdio;

void main()
{
    int i, j;
    readf("%s", &i);
    readf("%s", &j);
}

Run the program and provide the following as input:

42 43

The program terminates with

std.conv.ConvError: std.conv(1070): Can't convert value
`LockingTextReader(File(807637C),  )' of type LockingTextReader to type int

The reason is the white space.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Aug 16 2010
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4656


Andrei Alexandrescu <andrei metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |andrei metalanguage.com
         AssignedTo|nobody puremagic.com        |andrei metalanguage.com


-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jan 09 2011
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4656



--- Comment #1 from Andrei Alexandrescu <andrei metalanguage.com> 2011-05-09
09:18:02 PDT ---
This is by design. The example works when modified as follows:

import std.stdio;

void main()
{
    int i, j;
    readf("%s", &i);
    readf(" %s", &j);
}

The space before the second parameter tells readf to read and skip all
whitespace before attempting conversion.

I've implemented readf to be a fair amount more Nazi about whitespace than
scanf in an attempt to improve its precision. Scanf has been famously difficult
to use for complex input parsing and validation, and I attribute some of that
to its laissez-faire attitude toward whitespace. I'd be glad to relax some of
readf's insistence on precise whitespace handling if there's enough evidence
that that serves most of our users. I personally believe that the current
behavior (strict by default, easy to relax) is best.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
May 09 2011
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4656


Ali Cehreli <acehreli yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |INVALID


--- Comment #2 from Ali Cehreli <acehreli yahoo.com> 2011-05-09 10:42:43 PDT ---
My apologies for forgetting about this bug report. I have since then replaced
din and dout with stdin and stdout in D.ershane. The nazi whitespace behaviour
worked correctly and consistently in all of the examples.

Thank you,
Ali

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
May 09 2011
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4656


Andrei Alexandrescu <andrei metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|INVALID                     |


--- Comment #3 from Andrei Alexandrescu <andrei metalanguage.com> 2011-05-09
11:27:57 PDT ---
Let's keep it opened until the error message is fixed.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
May 09 2011
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4656


SomeDude <lovelydear mailmetrash.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lovelydear mailmetrash.com


--- Comment #4 from SomeDude <lovelydear mailmetrash.com> 2012-04-21 15:22:11
PDT ---
The original test case now produces this message:

PS E:\DigitalMars\dmd2\samples> rdmd bug.d
456 45646
std.conv.ConvException E:\DigitalMars\dmd2\windows\bin\..\..\src\phobos\std\conv.d(1779):
Unexpected ' ' when converting from type LockingTextReader to type int

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Apr 21 2012