[boost] Re: Re: Some comments on program_options/howto.html

From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-11-03 02:21:04

Peter Dimov wrote:

> Vladimir Prus wrote:
>>> The Response Files section shows example code for parsing a response
>>> file using Tokenizer. Why shouldn't one be able to use
>>> split_command_line instead? There doesn't seem to be any difference
>>> between a command line in string format and a response file.
>>
>> Good question. The problem is that split_winmain uses Windows-style
>> quoting rules, while tokenizer uses more Unix-like rules. I'm not
>> sure which syntax the response files should use.
> 
> My instinctive reaction is to provide both via an options argument to
> split_command_line (a name that would now be more appropriate). But I
> haven't devoted much time to thinking this through, so I may be wrong. :-)
> 
> In any event, the tokenization isn't much fun. I'd expect the library to
> provide a convenient mechanism for parsing a response file.

Noted.

>>> Also, response file support doesn't seem proper. Response files
>>> should work like this:
>>>
>>> @file1 --option=value @file2
>>>
>>> If file1 contains --option, it will be overriden by the command line.
>>> Similarly, all options in file2 will override both file1 and the
>>> command line --option=value. From a cursory look at the example,
>>> this doesn't seem to be the case, but I may be wrong.
>>
>> In the example, options on the command line will override options in
>> both response files. If that behaviour is not correct, I'll have to
>> modify the example by looking over vector of parsed options that's
>> returned by parse_command_line and expanding @ options. Do you think
>> that specifying
>> the same option in @file1 and @file2 is OK, and definition in @file2
>> should override the previous one? On the command line, two duplicated
>> assignments to a scalar option results in an error.
> 
> It should certainly be possible to override @file1 from the command line
> and from @file2 - this has many valid uses. 

Could you explain the uses for overriding @file1 from @file2? 

- Volodya