How do I select pages that have a template default value? - mediawiki

Question

So we have this template:
{| class="wikitable"
|-
| [[Saplings]] || ''{{{saplings|Lower}}}'' || [[Sappiness]] || ''{{{sappiness|Lowest}}}''
|-
| [[Matures]] || ''{{{matures|Average}}}'' || [[Effect (Tree)|Effect]] || ''{{{effect|None}}}''
|-
| [[Height]] || ''{{{height|Small}}}'' || [[Growth (Forestry)|Growth]] || ''{{{growth|Light}}}''
|-
| [[Girth]] || ''{{{girth|1}}}x{{{girth|1}}}'' || [[Tolerates]] || ''{{{tolerates| }}}''
|-
| [[Yield]] || ''{{{yield|Lowest}}}'' || [[Fruits]] || ''{{{fruits|None}}}''
|}<noinclude>{{Documentation}}</noinclude>
As you can see, all the fields have defaults. Now, in the actual pages, some leave off the default altogether (notice, no 'saplings'):
{{Tree-Attributes
| sappiness = Average
| fruits = Crabapple
}}
While others include the default explicitly:
{{Tree-Attributes
| saplings = Lower
| height = Large
| yield = Lowest
| sappiness = Lower
| fruits = none
| girth = 2
}}
Using the following DPL command, I can see all the ones with an explicit 'Lower' value. How do I get that and the ones left to default?
{{#dpl:
|category = Trees
|uses = Template:Tree
|includematch = ,/saplings\s*=\s*Lower\s*/i
|include = {Tree}:name, {Tree-Attributes}:speed
|table = class="wikitable",-,Lower
|tablerow = ²{P{{!}}%% Sapling{{!}}F}² [[%%]]<span style="display:none;">«nowiki»,«/nowiki»</span>
|allowcachedresults = true
}}
[Incidentally, I have no idea why there's a reference to attribute 'speed', when none is defined…]

Answer 1

Self-answer: I won't select this answer for a while, to see if anybody else comes up with something better.
I got the results I wanted by changing
includematch = ,/saplings\s*=\s*Lower\s*/i
to
includematch = ,/(saplings\s*=\s*Lower\s*){{!}}(^((?!saplings)(.{{!}}\n))+$)/i