Re: [RFC] scripts: kernel-doc: reduce repeated regex expressions into variables

From: Aditya Srivastava
Date: Sat Apr 24 2021 - 07:57:47 EST


On 23/4/21 6:51 pm, Matthew Wilcox wrote:
> On Fri, Apr 23, 2021 at 12:48:39AM +0530, Aditya Srivastava wrote:
>> +my $pointer_function = qr{([^\(]*\(\*)\s*\)\s*\(([^\)]*)\)};
>
> Is that a pointer-to-function? Or as people who write C usually call it,
> a function pointer? Wouldn't it be better to call it $function_pointer?
>
Will do it.

>> @@ -1210,8 +1211,14 @@ sub dump_struct($$) {
>> my $decl_type;
>> my $members;
>> my $type = qr{struct|union};
>> + my $packed = qr{__packed};
>> + my $aligned = qr{__aligned};
>> + my $cacheline_aligned_in_smp = qr{____cacheline_aligned_in_smp};
>> + my $cacheline_aligned = qr{____cacheline_aligned};
>
> I don't think those four definitions actually simplify anything.
>
>> + my $attribute = qr{__attribute__\s*\(\([a-z0-9,_\*\s\(\)]*\)\)}i;
>
> ... whereas this one definitely does.
>
>> - $members =~ s/\s*__attribute__\s*\(\([a-z0-9,_\*\s\(\)]*\)\)/ /gi;
>> - $members =~ s/\s*__aligned\s*\([^;]*\)/ /gos;
>> - $members =~ s/\s*__packed\s*/ /gos;
>> + $members =~ s/\s*$attribute/ /gi;
>> + $members =~ s/\s*$aligned\s*\([^;]*\)/ /gos;
>
> Maybe put the \s*\([^;]*\) into $aligned? Then it becomes a useful
> abstraction.

Actually, I had made these variables as they were repeated here and at
- my $definition_body =
qr{\{(.*)\}(?:\s*(?:__packed|__aligned|____cacheline_aligned_in_smp|____cacheline_aligned|__attribute__\s*\(\([a-z0-9,_\s\(\)]*\)\)))*};
+ my $definition_body =
qr{\{(.*)\}(?:\s*(?:$packed|$aligned|$cacheline_aligned_in_smp|$cacheline_aligned|$attribute))*};

So, defining them at a place might help.

What do you think?

>
>> - } elsif ($prototype =~ m/^()([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^(\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^(\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
>> - $prototype =~ m/^()([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
>> - $prototype =~ m/^(\w+\s+\w+\s*\*+\s*\w+\s*\*+\s*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/) {
>> + } elsif ($prototype =~ m/^()($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^(\w+)\s+($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^(\w+\s*\*+)\s*($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^(\w+\s+\w+)\s+($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s*\*+)\s*($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s+\w+)\s+($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*+)\s*($name)\s*$prototype_end1/ ||
>> + $prototype =~ m/^()($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+)\s+($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s*\*+)\s*($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+)\s+($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s*\*+)\s*($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s+\w+)\s+($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*+)\s*($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+)\s+($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+\s*\*+)\s*($name)\s*$prototype_end2/ ||
>> + $prototype =~ m/^(\w+\s+\w+\s*\*+\s*\w+\s*\*+\s*)\s*($name)\s*$prototype_end2/) {
>
> This is probably the best patch I've seen so far this year.
>
> Now, can we go further? For example:
> $prototype_end = $prototype_end1|$prototype_end2
> That would let us cut the number of lines here in half.
> > Can we create a definition for a variable number of \w and \s and '*'
> in the return type? In fact, can we define a regex that matches a type?
> So this would become:
>
>> + } elsif ($prototype =~ m/^($type)\s*($name)\s*$prototype_end/) {
>

I have been able to reduce these expressions furthermore. Will send a
v2 in few..

Thanks
Aditya