add relative-distance
#887
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| (in-package :relative-distance) | ||
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| (defun degree-of-separation (family-tree person-a person-b) |
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I think factoring this out into a few functions might be good. for example the tree parsing could be its own function
| (dolist (child children) | ||
| (unless (gethash child neighbors) | ||
| (setf (gethash child neighbors) (make-hash-table :test 'equal))) | ||
| (setf (gethash child (gethash parent neighbors)) t) |
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setf can take pairs of symbols and values so instead of (setf a b) (setf c d) you can do (setf a b c d). I personally think it looks nicer instead of two expressions.
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| (setf (gethash person-a visited) t) | ||
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| (loop while queue do |
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Starting to review the function I was thinking: "oh dolist not loop nice..." but now that I see loop I wonder why you didn't use loop above as well. You could do something like: (loop for (parent . child) in tree ...)
I don't care do vs. loop but think it would good to be consistent.
| (let ((current-neighbors (gethash current-person neighbors))) | ||
| (when current-neighbors | ||
| (maphash (lambda (neighbor _) | ||
| (unless (gethash neighbor visited) |
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Don't you get a STYLE-WARNING here about the unused symbol _? Use (declare (ignore _)) Maybe give it a reasonable name even though it is ignored...
| (current-degree (cdr current))) | ||
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| (when (equal current-person person-b) | ||
| (return-from degree-of-separation current-degree)) |
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How about you factor this loop so it evaluates to current-degree and then this whole function can evaluate to what this loop evaluates to?
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Just a general comment - the use of several |
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