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There's a null pointer exception that currently occurs when a rule maps

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onto neighbours, e.g.:
	(map #(population % :deer) (get-neighbours world cell))
I've worked around it for now by commenting out the rules which do this,
but the bug is in get-neighbours and should be fixed there.
This commit is contained in:
simon 2014-07-04 09:10:58 +01:00
parent 8a00e5c0da
commit 6320b3e5b0
2 changed files with 20 additions and 18 deletions
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30
src/mw_engine/natural_rules.clj
View file

@ -87,12 +87,12 @@
(cond (> (* (population cell :deer) 10) (get-int cell :fertility))
(merge cell {:deer (int (/ (get-int cell :fertility) 10))})))
;; deer gradually spread through the world by breeding or migrating.
(fn [cell world]
(let [n (apply + (map #(population % :deer) (get-neighbours world cell)))]
(cond (and
(= (population cell :deer) 0)
(>= n 2))
(merge cell {:deer (int (/ n 2))}))))
;; (fn [cell world]
;; (let [n (apply + (map #(population % :deer) (get-neighbours world cell)))]
;; (cond (and
;; (= (population cell :deer) 0)
;; (>= n 2))
;; (merge cell {:deer (int (/ n 2))}))))
;; deer breed.
(fn [cell world]
(cond
@ -110,16 +110,16 @@
(merge cell {:wolves 2})))
;; if there are not enough deer to sustain the population of wolves,
;; some wolves die or move on.
(fn [cell world]
(cond (> (population cell :wolves) (population cell :deer))
(merge cell {:wolves 0})))
(fn [cell world]
(cond (> (population cell :wolves) (population cell :deer))
(merge cell {:wolves 0})))
;; wolves gradually spread through the world by breeding or migrating.
(fn [cell world]
(let [n (apply + (map #(population % :wolves) (get-neighbours world cell)))]
(cond (and
(= (population cell :wolves) 0)
(>= n 2))
(merge cell {:wolves 2}))))
;; (fn [cell world]
;; (let [n (apply + (map #(population % :wolves) (get-neighbours world cell)))]
;; (cond (and
;; (= (population cell :wolves) 0)
;; (>= n 2))
;; (merge cell {:wolves 2}))))
;; wolves breed.
(fn [cell world]
(cond

8
src/mw_engine/utils.clj
View file

@ -30,9 +30,11 @@
(defn get-int
"Get the value of a property expected to be an integer from a map; if not present (or not an integer) return 0."
[map key]
(let [v (map key)]
(cond (integer? v) v
true 0)))
(cond map
(let [v (map key)]
(cond (and v (integer? v)) v
true 0))
true (throw (Exception. "No map passed?"))))
(defn population
"Return the population of this species in this cell.