simon/mw-parser
1
0
Fork 0
Code Issues Pull requests Actions Packages Projects Releases Wiki Activity

Trying to get code quality up, but in the process I've broken something -

Browse source 
I think, the simplifier.
This commit is contained in:
simon 2016-08-13 19:45:43 +01:00
parent d2a73ba408
commit 3168c1b2fb
9 changed files with 298 additions and 183 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
src/mw_parser/bulk.clj
View file

@ -1,13 +1,32 @@
;; parse multiple rules from a stream, possibly a file - although the real (ns ^{:doc "parse multiple rules from a stream, possibly a file."
;; objective is to parse rules out of a block of text from a textarea :author "Simon Brooke"}
mw-parser.bulk
(ns mw-parser.bulk
(:use mw-parser.declarative (:use mw-parser.declarative
mw-engine.utils mw-engine.utils
clojure.java.io clojure.java.io
[clojure.string :only [split trim]]) [clojure.string :only [split trim]])
(:import (java.io BufferedReader StringReader))) (:import (java.io BufferedReader StringReader)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defn comment? (defn comment?
"Is this `line` a comment?" "Is this `line` a comment?"
[line] [line]

37
src/mw_parser/core.clj
View file

@ -1,3 +1,30 @@
(ns ^{:doc "A very simple parser which parses production rules."
:author "Simon Brooke"}
mw-parser.core
(:use mw-engine.utils
[clojure.string :only [split trim triml]])
(:gen-class)
)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; A very simple parser which parses production rules of the following forms: ;; A very simple parser which parses production rules of the following forms:
;; ;;
;; * "if altitude is less than 100 and state is forest then state should be climax and deer should be 3" ;; * "if altitude is less than 100 and state is forest then state should be climax and deer should be 3"
@ -24,18 +51,14 @@
;; ;;
;; This is the parser that is actually used currently; but see also insta.clj, ;; This is the parser that is actually used currently; but see also insta.clj,
;; which is potentially a much better parser but does not quite work yet. ;; which is potentially a much better parser but does not quite work yet.
;;
(ns mw-parser.core ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(:use mw-engine.utils
[clojure.string :only [split trim triml]])
(:gen-class)
)
(declare parse-conditions) (declare parse-conditions)
(declare parse-not-condition) (declare parse-not-condition)
(declare parse-simple-condition) (declare parse-simple-condition)
;; a regular expression which matches string representation of numbers ;; a regular expression which matches string representation of positive numbers
(def re-number #"^[0-9.]*$") (def re-number #"^[0-9.]*$")
;; error thrown when an attempt is made to set a reserved property ;; error thrown when an attempt is made to set a reserved property

39
src/mw_parser/declarative.clj
View file

@ -1,11 +1,31 @@
(ns mw-parser.declarative (ns ^{:doc "A very simple parser which parses production rules."
(:use mw-engine.utils :author "Simon Brooke"}
mw-parser.utils mw-parser.declarative
(:require [instaparse.core :as insta]
[clojure.string :refer [split trim triml]]
[mw-parser.errors :as pe] [mw-parser.errors :as pe]
[mw-parser.generate :as pg] [mw-parser.generate :as pg]
[mw-parser.simplify :as ps] [mw-parser.simplify :as ps]
[clojure.string :only [split trim triml]]) [mw-parser.utils :refer [rule?]]))
(:require [instaparse.core :as insta]))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(def grammar (def grammar
@ -93,3 +113,12 @@
(compile-rule rule-text false))) (compile-rule rule-text false)))
(ps/simplify
(parse-rule
"if more than 2 neighbours have altitude equal to 11 then state should be beach"))
(pg/generate
(ps/simplify
(parse-rule
"if more than 2 neighbours have altitude equal to 11 then state should be beach")))

25
src/mw_parser/errors.clj
View file

@ -1,4 +1,27 @@
(ns mw-parser.errors) (ns ^{:doc "Display parse errors in a format which makes it easy for the user
to see where the error occurred."
:author "Simon Brooke"}
mw-parser.errors)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; error thrown when an attempt is made to set a reserved property ;; error thrown when an attempt is made to set a reserved property
(def reserved-properties-error (def reserved-properties-error

56
src/mw_parser/generate.clj
View file

@ -1,8 +1,29 @@
(ns mw-parser.generate (ns ^{:doc "Generate Clojure source from simplified parse trees."
(:use mw-engine.utils :author "Simon Brooke"}
mw-parser.utils mw-parser.generate
(:require [mw-engine.utils :refer []]
[mw-parser.utils :refer [assert-type TODO]]
[mw-parser.errors :as pe])) [mw-parser.errors :as pe]))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(declare generate generate-action) (declare generate generate-action)
@ -24,6 +45,8 @@
(defn generate-condition (defn generate-condition
"From this `tree`, assumed to be a syntactically correct condition clause,
generate and return the appropriate clojure fragment."
[tree] [tree]
(assert-type tree :CONDITION) (assert-type tree :CONDITION)
(generate (second tree))) (generate (second tree)))
@ -31,18 +54,24 @@
(defn generate-conjunct-condition (defn generate-conjunct-condition
[tree] [tree]
"From this `tree`, assumed to be a syntactically conjunct correct condition clause,
generate and return the appropriate clojure fragment."
(assert-type tree :CONJUNCT-CONDITION) (assert-type tree :CONJUNCT-CONDITION)
(cons 'and (map generate (rest tree)))) (cons 'and (map generate (rest tree))))
(defn generate-disjunct-condition (defn generate-disjunct-condition
"From this `tree`, assumed to be a syntactically correct disjunct condition clause,
generate and return the appropriate clojure fragment."
[tree] [tree]
(assert-type tree :DISJUNCT-CONDITION) (assert-type tree :DISJUNCT-CONDITION)
(cons 'or (map generate (rest tree)))) (cons 'or (map generate (rest tree))))
(defn generate-ranged-property-condition (defn generate-ranged-property-condition
"Generate a property condition where the expression is a numeric range" "From this `tree`, assumed to be a syntactically property condition clause for
this `property` where the `expression` is a numeric range, generate and return
the appropriate clojure fragment."
[tree property expression] [tree property expression]
(assert-type tree :PROPERTY-CONDITION) (assert-type tree :PROPERTY-CONDITION)
(assert-type (nth tree 3) :RANGE-EXPRESSION) (assert-type (nth tree 3) :RANGE-EXPRESSION)
@ -55,7 +84,9 @@
(defn generate-disjunct-property-condition (defn generate-disjunct-property-condition
"Generate a property condition where the expression is a disjunct expression. "From this `tree`, assumed to be a syntactically property condition clause
where the expression is a a disjunction, generate and return
the appropriate clojure fragment.
TODO: this is definitely still wrong!" TODO: this is definitely still wrong!"
([tree] ([tree]
(let [property (generate (second tree)) (let [property (generate (second tree))
@ -70,6 +101,8 @@
(defn generate-property-condition (defn generate-property-condition
"From this `tree`, assumed to be a syntactically property condition clause,
generate and return the appropriate clojure fragment."
([tree] ([tree]
(assert-type tree :PROPERTY-CONDITION) (assert-type tree :PROPERTY-CONDITION)
(if (if
@ -100,6 +133,8 @@
(defn generate-qualifier (defn generate-qualifier
"From this `tree`, assumed to be a syntactically correct qualifier,
generate and return the appropriate clojure fragment."
[tree] [tree]
(if (if
(= (count tree) 2) (= (count tree) 2)
@ -109,6 +144,8 @@
(defn generate-simple-action (defn generate-simple-action
"From this `tree`, assumed to be a syntactically correct simple action,
generate and return the appropriate clojure fragment."
([tree] ([tree]
(assert-type tree :SIMPLE-ACTION) (assert-type tree :SIMPLE-ACTION)
(generate-simple-action tree [])) (generate-simple-action tree []))
@ -126,6 +163,8 @@
(defn generate-probable-action (defn generate-probable-action
"From this `tree`, assumed to be a syntactically correct probable action,
generate and return the appropriate clojure fragment."
([tree] ([tree]
(assert-type tree :PROBABLE-ACTION) (assert-type tree :PROBABLE-ACTION)
(generate-probable-action tree [])) (generate-probable-action tree []))
@ -142,6 +181,8 @@
(defn generate-action (defn generate-action
"From this `tree`, assumed to be a syntactically correct action,
generate and return the appropriate clojure fragment."
[tree others] [tree others]
(case (first tree) (case (first tree)
:ACTIONS (generate-action (first tree) others) :ACTIONS (generate-action (first tree) others)
@ -151,6 +192,8 @@
(defn generate-multiple-actions (defn generate-multiple-actions
"From this `tree`, assumed to be one or more syntactically correct actions,
generate and return the appropriate clojure fragment."
[tree] [tree]
(assert-type tree :ACTIONS) (assert-type tree :ACTIONS)
(generate-action (first (rest tree)) (second (rest tree)))) (generate-action (first (rest tree)) (second (rest tree))))
@ -166,6 +209,8 @@
(defn generate-numeric-expression (defn generate-numeric-expression
"From this `tree`, assumed to be a syntactically correct numeric expression,
generate and return the appropriate clojure fragment."
[tree] [tree]
(assert-type tree :NUMERIC-EXPRESSION) (assert-type tree :NUMERIC-EXPRESSION)
(case (count tree) (case (count tree)
@ -182,6 +227,7 @@
([tree] ([tree]
(assert-type tree :NEIGHBOURS-CONDITION) (assert-type tree :NEIGHBOURS-CONDITION)
(case (first (second tree)) (case (first (second tree))
:NUMBER (read-string (second (second tree)))
:QUANTIFIER (generate-neighbours-condition tree (first (second (second tree)))) :QUANTIFIER (generate-neighbours-condition tree (first (second (second tree))))
:QUALIFIER (cons (generate (second tree)) (rest (generate (nth tree 2)))))) :QUALIFIER (cons (generate (second tree)) (rest (generate (nth tree 2))))))
([tree quantifier-type] ([tree quantifier-type]

92
src/mw_parser/simplifier.clj
View file

@ -1,92 +0,0 @@
(ns mw-parser.simplifier
(:use mw-engine.utils
mw-parser.parser))
(declare simplify)
(defn simplify-qualifier
"Given that this `tree` fragment represents a qualifier, what
qualifier is that?"
[tree]
(cond
(empty? tree) nil
(and (coll? tree)
(member? (first tree) '(:EQUIVALENCE :COMPARATIVE))) tree
(coll? (first tree)) (or (simplify-qualifier (first tree))
(simplify-qualifier (rest tree)))
(coll? tree) (simplify-qualifier (rest tree))
true tree))
(defn simplify-second-of-two
"There are a number of possible simplifications such that if the `tree` has
only two elements, the second is semantically sufficient."
[tree]
(if (= (count tree) 2) (simplify (nth tree 1)) tree))
(defn simplify-some
"'some' is the same as 'more than zero'"
[tree]
[:COMPARATIVE '> 0])
(defn simplify-none
"'none' is the same as 'zero'"
[tree]
[:COMPARATIVE '= 0])
(defn simplify-all
"'all' isn't actually the same as 'eight', because cells at the edges of the world have
fewer than eight neighbours; but it's a simplifying (ha!) assumption for now."
[tree]
[:COMPARATIVE '= 8])
(defn simplify-quantifier
"If this quantifier is a number, 'simplifiy' it into a comparative whose operator is '='
and whose quantity is that number. This is actually more complicated but makes generation easier."
[tree]
(if (number? (second tree)) [:COMPARATIVE '= (second tree)] (simplify (second tree))))
(defn simplify
"Simplify/canonicalise this `tree`. Opportunistically replace complex fragments with
semantically identical simpler fragments"
[tree]
(if
(coll? tree)
(case (first tree)
:SPACE nil
:QUALIFIER (simplify-qualifier tree)
:CONDITIONS (simplify-second-of-two tree)
:CONDITION (simplify-second-of-two tree)
:EXPRESSION (simplify-second-of-two tree)
:COMPARATIVE (simplify-second-of-two tree)
:QUANTIFIER (simplify-quantifier tree)
:VALUE (simplify-second-of-two tree)
:PROPERTY (simplify-second-of-two tree)
:ACTIONS (simplify-second-of-two tree)
:ACTION (simplify-second-of-two tree)
:ALL (simplify-all tree)
:SOME (simplify-some tree)
:NONE (simplify-none tree)
(remove nil? (map simplify tree)))
tree))
(simplify (parse-rule "if state is climax and 4 neighbours have state equal to fire then 3 chance in 5 state should be fire"))
(simplify (parse-rule "if state is climax and no neighbours have state equal to fire then 3 chance in 5 state should be fire"))
(simplify (parse-rule "if state is in grassland or pasture or heath and more than 4 neighbours have state equal to water then state should be village"))
(simplify (parse-rule "if 6 neighbours have state equal to water then state should be village"))
(simplify (parse-rule "if fertility is between 55 and 75 then state should be climax"))
(simplify (parse-rule "if state is forest then state should be climax"))
(simplify (parse-rule "if state is in grassland or pasture or heath and more than 4 neighbours have state equal to water then state should be village"))
(simplify (parse-rule "if altitude is less than 100 and state is forest then state should be climax and deer should be 3"))
(simplify (parse-rule "if altitude is 100 or fertility is 25 then state should be heath and fertility should be 24.3"))
(simplify (parse-rule "if altitude is 100 or fertility is 25 then state should be heath"))
(simplify (parse-rule "if deer is more than 2 and wolves is 0 and fertility is more than 20 then deer should be deer + 2"))
(simplify (parse-rule "if deer is more than 1 and wolves is more than 1 then deer should be deer - wolves"))
(simplify (parse-rule "if state is grassland and 4 neighbours have state equal to water then state should be village"))

52
src/mw_parser/simplify.clj
View file

@ -1,6 +1,27 @@
(ns mw-parser.simplify (ns ^{:doc "Simplify a parse tree."
(:use mw-engine.utils :author "Simon Brooke"}
mw-parser.utils)) mw-parser.simplify
(:require [mw-engine.utils :refer [member?]]))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(declare simplify) (declare simplify)
@ -21,7 +42,14 @@
"There are a number of possible simplifications such that if the `tree` has "There are a number of possible simplifications such that if the `tree` has
only two elements, the second is semantically sufficient." only two elements, the second is semantically sufficient."
[tree] [tree]
(if (= (count tree) 2) (simplify (second tree)) tree)) (if (= (count tree) 2) (simplify (nth tree 1)) tree))
(defn simplify-quantifier
"If this quantifier is a number, 'simplifiy' it into a comparative whose operator is '='
and whose quantity is that number. This is actually more complicated but makes generation easier."
[tree]
(if (number? (second tree)) [:COMPARATIVE '= (second tree)] (simplify (second tree))))
(defn simplify (defn simplify
@ -31,18 +59,24 @@
(if (if
(coll? tree) (coll? tree)
(case (first tree) (case (first tree)
;; 'all' isn't actually the same as 'eight', because cells at the edges of the world have
;; fewer than eight neighbours; but it's a simplifying (ha!) assumption for now."
;; TODO: fix this so it actually works.
:ALL [:COMPARATIVE '= 8]
:ACTION (simplify-second-of-two tree) :ACTION (simplify-second-of-two tree)
:ACTIONS (cons (first tree) (simplify (rest tree))) :ACTIONS (simplify-second-of-two tree)
:CHANCE-IN nil
:COMPARATIVE (simplify-second-of-two tree) :COMPARATIVE (simplify-second-of-two tree)
:CONDITION (simplify-second-of-two tree) :CONDITION (simplify-second-of-two tree)
:CONDITIONS (simplify-second-of-two tree) :CONDITIONS (simplify-second-of-two tree)
:EXPRESSION (simplify-second-of-two tree) :EXPRESSION (simplify-second-of-two tree)
:NONE [:COMPARATIVE '= 0]
:NUMBER tree
:PROPERTY (simplify-second-of-two tree) :PROPERTY (simplify-second-of-two tree)
:PROPERTY-CONDITION-OR-EXPRESSION (simplify-second-of-two tree) :QUALIFIER (simplify-qualifier tree)
:QUANTIFIER (simplify-quantifier tree)
:SOME [:COMPARATIVE '> 0]
:SPACE nil :SPACE nil
:THEN nil
:AND nil
:VALUE (simplify-second-of-two tree) :VALUE (simplify-second-of-two tree)
(remove nil? (map simplify tree))) (remove nil? (map simplify tree)))
tree)) tree))

23
src/mw_parser/utils.clj
View file

@ -1,4 +1,25 @@
(ns mw-parser.utils) (ns ^{:doc "Utilities used in more than one namespace within the parser."
:author "Simon Brooke"}
mw-parser.utils)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 2
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
;; USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defn rule? (defn rule?

12
test/mw_parser/declarative_test.clj
View file

@ -472,3 +472,15 @@
(is (nil? (apply afn (list {:x 0 :y 1} world))) (is (nil? (apply afn (list {:x 0 :y 1} world)))
"Middle cell of the strip has only two high neighbours, so rule should not fire.")) "Middle cell of the strip has only two high neighbours, so rule should not fire."))
)) ))
(deftest regression-tests
(testing "Rule in default set which failed on switchover to declarative rules"
(let [afn (compile-rule "if state is scrub then 1 chance in 5 state should be forest")
world (transform-world
(make-world 3 3)
(list (compile-rule "if x is 2 then altitude should be 11")
(compile-rule "if x is less than 2 then state should be scrub")))]
(is (= (:state (apply afn (list {:x 1 :y 1} world))) :forest)
"Centre cell is scrub, so rule should fire")
(is (= (:state (apply afn (list {:x 2 :y 1} world))) :beach)
"Middle cell of the strip is not scrub, so rule should not fire."))))