Re: [Scid-users] (patch) scmerge may take merged files from standard input instead of command line

[Marcin K. <Mar...@so...>]

>> No, no, no, it should be continue!
>>
>> This is just semantics of handling possible empty lines. In case of 
>> continue, we just ignore empty lines and keep reading stdin. In case 
>> of break, first empty line abort the process.
>> The process is over when stdin is finished, fgets returns false then 
>> and while loop is over. stdin is finished
>> - if you run it manually, when you press Ctrl-D
>> - if you redirect from pipe or file - when it is finishe
> I thought a blank line to abort the process was more intuitive than 
> Ctrl-D (moreover I don't know if Ctrl -D is correctly handled under 
> Windows).
On Windows that's Ctrl-Z if I remember correctly. But neither of those 
shortcuts is of any importance, no one will be ever writing names of the 
bases to merge using keyboard on the terminal/console (maybe except 
testing ;-)). The feature is to be used for shell scripts and for 
reading bases list from the file. In thise cases end-of-file works 
perfectly well as the signal of end of data.


> And in a script, there shouldn't be any blank lines : for example 
> "find . -name '*.si3' ..........." does not generate blank lines.
Single find, does not. But if you try to merge a few finds and feed 
those to the command, then empty lines may happen.

Also, empty lines may be useful if somebody prepares such bases list by 
hand, to separate groups.

> So I don't see any use case where the process should continue after a 
> blank line.
The case where it would be necessary to break is even more difficult to 
find.

At the same time aborting on the blank line is likely to cause the 
problems. Some shells report an error if the consuming side of pipe ends 
before whole input is read.

To summarize: this is of course corner case, in most situations no empty 
line will ever happen on input. But if it ever happens, continuing the 
work seems to be better solution (and suits the way most shell utils 
work....).