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Major restructuring, switched over to use the new declarative parser.

Browse source 
Some rules in the bulk test file no longer parse, but all rules in the
demonstration rule-sets do.
This commit is contained in:
simon 2016-08-10 20:11:17 +01:00
parent 9836cbff50
commit d2a73ba408
8 changed files with 488 additions and 444 deletions
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2
src/mw_parser/bulk.clj
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@ -2,7 +2,7 @@
;; objective is to parse rules out of a block of text from a textarea
(ns mw-parser.bulk
(:use mw-parser.core
(:use mw-parser.declarative
mw-engine.utils
clojure.java.io
[clojure.string :only [split trim]])

418
src/mw_parser/declarative.clj
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@ -1,19 +1,13 @@
(ns mw-parser.declarative
(:use mw-engine.utils
mw-parser.utils
[mw-parser.errors :as pe]
[mw-parser.generate :as pg]
[mw-parser.simplify :as ps]
[clojure.string :only [split trim triml]])
(:require [instaparse.core :as insta]))
;; error thrown when an attempt is made to set a reserved property
(def reserved-properties-error
"The properties 'x' and 'y' of a cell are reserved and should not be set in rule actions")
;; error thrown when a rule cannot be parsed. Slots are for
;; (1) rule text
;; (2) cursor showing where in the rule text the error occurred
;; (3) the reason for the error
(def bad-parse-error "I did not understand:\n '%s'\n %s\n %s")
(def grammar
;; in order to simplify translation into other natural languages, all
;; TOKENS within the parser should be unambiguous
@ -69,395 +63,33 @@
SPACE := #' *'";
)
(defn TODO
"Marker to indicate I'm not yet finished!"
[message]
message)
(declare generate generate-action simplify)
(defn suitable-fragment?
"Return `true` if `tree-fragment` appears to be a tree fragment of the expected `type`."
[tree-fragment type]
(and (coll? tree-fragment)
(= (first tree-fragment) type)))
(defn assert-type
"If `tree-fragment` is not a tree fragment of the expected `type`, throw an exception."
[tree-fragment type]
(assert (suitable-fragment? tree-fragment type)
(throw (Exception. (format "Expected a %s fragment" type)))))
(defn search-tree
"Return the first element of this tree which has this tag in a depth-first, left-to-right search"
[tree tag]
(cond
(= (first tree) tag) tree
:else (first
(remove nil?
(map
#(search-tree % tag)
(rest tree))))))
(defn generate-rule
"From this `tree`, assumed to be a syntactically correct rule specification,
generate and return the appropriate rule as a function of two arguments."
[tree]
(assert-type tree :RULE)
(list 'fn ['cell 'world] (list 'if (generate (nth tree 2)) (generate (nth tree 3)))))
(defn generate-conditions
"From this `tree`, assumed to be a syntactically correct conditions clause,
generate and return the appropriate clojure fragment."
[tree]
(assert-type tree :CONDITIONS)
(generate (second tree)))
(defn generate-condition
[tree]
(assert-type tree :CONDITION)
(generate (second tree)))
(defn generate-conjunct-condition
[tree]
(assert-type tree :CONJUNCT-CONDITION)
(cons 'and (map generate (rest tree))))
(defn generate-disjunct-condition
[tree]
(assert-type tree :DISJUNCT-CONDITION)
(cons 'or (map generate (rest tree))))
(defn generate-ranged-property-condition
"Generate a property condition where the expression is a numeric range"
[tree property expression]
(assert-type tree :PROPERTY-CONDITION)
(assert-type (nth tree 3) :RANGE-EXPRESSION)
(let [l1 (generate (nth expression 2))
l2 (generate (nth expression 4))
pv (list property 'cell)]
(list 'let ['lower (list 'min l1 l2)
'upper (list 'max l1 l2)]
(list 'and (list '>= pv 'lower)(list '<= pv 'upper)))))
(defn generate-disjunct-property-condition
"Generate a property condition where the expression is a disjunct expression.
TODO: this is definitely still wrong!"
([tree]
(let [property (generate (second tree))
qualifier (generate (nth tree 2))
expression (generate (nth tree 3))]
(generate-disjunct-property-condition tree property qualifier expression)))
([tree property qualifier expression]
(let [e (list 'some (list 'fn ['i] '(= i value)) (list 'quote expression))]
(list 'let ['value (list property 'cell)]
(if (= qualifier '=) e
(list 'not e))))))
(defn generate-property-condition
([tree]
(assert-type tree :PROPERTY-CONDITION)
(if
(and (= (count tree) 2) (= (first (second tree)) :SYMBOL))
;; it's a shorthand for 'state equal to symbol'. This should probably have
;; been handled in simplify...
(generate-property-condition
(list
:PROPERTY-CONDITION
'(:SYMBOL "state")
'(:QUALIFIER (:EQUIVALENCE (:EQUAL "equal to")))
(second tree)))
;; otherwise...
(generate-property-condition tree (first (nth tree 3)))))
([tree expression-type]
(assert-type tree :PROPERTY-CONDITION)
(let [property (generate (second tree))
qualifier (generate (nth tree 2))
e (generate (nth tree 3))
expression (cond
(and (not (= qualifier '=)) (keyword? e)) (list 'or (list e 'cell) e)
(and (not (= qualifier 'not=)) (keyword? e)) (list 'or (list e 'cell) e)
:else e)]
(case expression-type
:DISJUNCT-EXPRESSION (generate-disjunct-property-condition tree property qualifier expression)
:RANGE-EXPRESSION (generate-ranged-property-condition tree property expression)
(list qualifier (list property 'cell) expression)))))
(defn generate-qualifier
[tree]
(if
(= (count tree) 2)
(generate (second tree))
;; else
(generate (nth tree 2))))
(defn generate-simple-action
([tree]
(assert-type tree :SIMPLE-ACTION)
(generate-simple-action tree []))
([tree others]
(assert-type tree :SIMPLE-ACTION)
(let [property (generate (second tree))
expression (generate (nth tree 3))]
(if (or (= property :x) (= property :y))
(throw (Exception. reserved-properties-error))
(list 'merge
(if (empty? others) 'cell
;; else
(generate others))
{property expression})))))
(defn generate-probable-action
([tree]
(assert-type tree :PROBABLE-ACTION)
(generate-probable-action tree []))
([tree others]
(assert-type tree :PROBABLE-ACTION)
(let
[chances (generate (nth tree 1))
total (generate (nth tree 2))
action (generate-action (nth tree 3) others)]
;; TODO: could almost certainly be done better with macro syntax
(list 'if
(list '< (list 'rand total) chances)
action))))
(defn generate-action
[tree others]
(case (first tree)
:ACTIONS (generate-action (first tree) others)
:SIMPLE-ACTION (generate-simple-action tree others)
:PROBABLE-ACTION (generate-probable-action tree others)
(throw (Exception. (str "Not a known action type: " (first tree))))))
(defn generate-multiple-actions
[tree]
(assert-type tree :ACTIONS)
(generate-action (first (rest tree)) (second (rest tree))))
(defn generate-disjunct-value
"Generate a disjunct value. Essentially what we need here is to generate a
flat list of values, since the `member` has already been taken care of."
[tree]
(assert-type tree :DISJUNCT-VALUE)
(if (= (count tree) 4)
(cons (generate (second tree)) (generate (nth tree 3)))
(list (generate (second tree)))))
(defn generate-numeric-expression
[tree]
(assert-type tree :NUMERIC-EXPRESSION)
(case (count tree)
4 (let [[p operator expression] (rest tree)
property (if (number? p) p (list p 'cell))]
(list (generate operator) (generate property) (generate expression)))
(case (first (second tree))
:SYMBOL (list (keyword (second (second tree))) 'cell)
(generate (second tree)))))
(defn generate-neighbours-condition
"Generate code for a condition which refers to neighbours."
([tree]
(assert-type tree :NEIGHBOURS-CONDITION)
(case (first (second tree))
:QUANTIFIER (generate-neighbours-condition tree (first (second (second tree))))
:QUALIFIER (cons (generate (second tree)) (rest (generate (nth tree 2))))))
([tree quantifier-type]
(let [quantifier (second tree)
pc (generate (nth tree 4))]
(case quantifier-type
:NUMBER (generate-neighbours-condition '= (read-string (second (second quantifier))) pc 1)
:SOME (generate-neighbours-condition '> 0 pc 1)
:MORE (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '> value pc 1))
:LESS (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '< value pc 1))
)))
([comp1 quantity property-condition distance]
(list comp1
(list 'count
(list 'remove 'false?
(list 'map (list 'fn ['cell] property-condition)
(list 'mw-engine.utils/get-neighbours 'world 'cell distance)))) quantity))
([comp1 quantity property-condition]
(generate-neighbours-condition comp1 quantity property-condition 1)))
(defn generate-within-condition
"Generate code for a condition which refers to neighbours within a specified distance.
NOTE THAT there's clearly masses of commonality between this and
`generate-neighbours-condition`, and that some refactoring is almost certainly
desirable. It may be that it's better to simplify a `NEIGHBOURS-CONDITION`
into a `WITHIN-CONDITION` in the simplification stage."
([tree]
(assert-type tree :WITHIN-CONDITION)
(case (first (second tree))
:QUANTIFIER (generate-within-condition tree (first (second (second tree))))
:QUALIFIER (TODO "qualified within... help!")))
([tree quantifier-type]
(let [quantifier (second tree)
distance (generate (nth tree 4))
pc (generate (nth tree 6))]
(case quantifier-type
:NUMBER (generate-neighbours-condition '= (read-string (second (second quantifier))) pc distance)
:SOME (generate-neighbours-condition '> 0 pc distance)
:MORE (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '> value pc distance))
:LESS (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '< value pc distance))
))))
(defn generate
"Generate code for this (fragment of a) parse tree"
[tree]
(if
(coll? tree)
(case (first tree)
:ACTIONS (generate-multiple-actions tree)
:COMPARATIVE (generate (second tree))
:COMPARATIVE-QUALIFIER (generate (second tree))
:CONDITION (generate-condition tree)
:CONDITIONS (generate-conditions tree)
:CONJUNCT-CONDITION (generate-conjunct-condition tree)
:DISJUNCT-CONDITION (generate-disjunct-condition tree)
:DISJUNCT-EXPRESSION (generate (nth tree 2))
:DISJUNCT-VALUE (generate-disjunct-value tree)
:EQUIVALENCE '=
:EXPRESSION (generate (second tree))
:LESS '<
:MORE '>
:NEGATED-QUALIFIER (case (generate (second tree))
= 'not=
> '<
< '>)
:NEIGHBOURS-CONDITION (generate-neighbours-condition tree)
:NUMERIC-EXPRESSION (generate-numeric-expression tree)
:NUMBER (read-string (second tree))
:OPERATOR (symbol (second tree))
:PROBABLE-ACTION (generate-probable-action tree)
:PROPERTY (list (generate (second tree)) 'cell) ;; dubious - may not be right
:PROPERTY-CONDITION (generate-property-condition tree)
:QUALIFIER (generate-qualifier tree)
:RULE (generate-rule tree)
:SIMPLE-ACTION (generate-simple-action tree)
:SYMBOL (keyword (second tree))
:VALUE (generate (second tree))
:WITHIN-CONDITION (generate-within-condition tree)
(map generate tree))
tree))
(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 (second tree)) tree))
(defn rule?
"Return true if the argument appears to be a parsed rule tree, else false."
[maybe-rule]
(and (coll? maybe-rule) (= (first maybe-rule) :RULE)))
(defn simplify
"Simplify/canonicalise this `tree`. Opportunistically replace complex fragments with
semantically identical simpler fragments"
[tree]
(if
(coll? tree)
(case (first tree)
:ACTION (simplify-second-of-two tree)
:ACTIONS (cons (first tree) (simplify (rest tree)))
:CHANCE-IN nil
:COMPARATIVE (simplify-second-of-two tree)
:CONDITION (simplify-second-of-two tree)
:CONDITIONS (simplify-second-of-two tree)
:EXPRESSION (simplify-second-of-two tree)
:PROPERTY (simplify-second-of-two tree)
:PROPERTY-CONDITION-OR-EXPRESSION (simplify-second-of-two tree)
:SPACE nil
:THEN nil
:AND nil
:VALUE (simplify-second-of-two tree)
(remove nil? (map simplify tree)))
tree))
(def parse-rule
"Parse the argument, assumed to be a string in the correct syntax, and return a parse tree."
(insta/parser grammar))
(defn explain-parse-error-reason
"Attempt to explain the reason for the parse error."
[reason]
(str "Expecting one of (" (apply str (map #(str (:expecting %) " ") reason)) ")"))
(defn parser-error-to-map
[parser-error]
(let [m (reduce (fn [map item](merge map {(first item)(second item)})) {} parser-error)
reason (map
#(reduce (fn [map item] (merge {(first item) (second item)} map)) {} %)
(:reason m))]
(merge m {:reason reason})))
(defn throw-parse-exception
"Construct a helpful error message from this `parser-error`, and throw an exception with that message."
[parser-error]
(assert (coll? parser-error) "Expected a paser error structure?")
(let
[
;; the error structure is a list, such that each element is a list of two items, and
;; the first element in each sublist is a keyword. Easier to work with it as a map
error-map (parser-error-to-map parser-error)
text (:text error-map)
reason (explain-parse-error-reason (:reason error-map))
;; rules have only one line, by definition; we're interested in the column
column (if (:column error-map)(:column error-map) 0)
;; create a cursor to point to that column
cursor (apply str (reverse (conj (repeat column " ") "^")))
message (format bad-parse-error text cursor reason)
]
(throw (Exception. message))))
(defn compile-rule
"Compile this `rule`, assumed to be a string with appropriate syntax, into a function of two arguments,
a `cell` and a `world`, having the same semantics."
[rule]
(assert (string? rule))
(let [tree (simplify (parse-rule rule))]
(if (rule? tree) (eval (generate tree))
(throw-parse-exception tree))))
"Parse this `rule-text`, a string conforming to the grammar of MicroWorld rules,
into Clojure source, and then compile it into an anonymous
function object, getting round the problem of binding mw-engine.utils in
the compiling environment. If `return-tuple?` is present and true, return
a list comprising the anonymous function compiled, and the function from
which it was compiled.
Throws an exception if parsing fails."
([rule-text return-tuple?]
(assert (string? rule-text))
(let [rule (trim rule-text)
tree (ps/simplify (parse-rule rule))
afn (if (rule? tree) (eval (pg/generate tree))
;; else
(pe/throw-parse-exception tree))]
(if return-tuple?
(list afn rule)
;; else
afn)))
([rule-text]
(compile-rule rule-text false)))

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src/mw_parser/errors.clj Normal file
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@ -0,0 +1,45 @@
(ns mw-parser.errors)
;; error thrown when an attempt is made to set a reserved property
(def reserved-properties-error
"The properties 'x' and 'y' of a cell are reserved and should not be set in rule actions")
;; error thrown when a rule cannot be parsed. Slots are for
;; (1) rule text
;; (2) cursor showing where in the rule text the error occurred
;; (3) the reason for the error
(def bad-parse-error "I did not understand:\n '%s'\n %s\n %s")
(defn- explain-parse-error-reason
"Attempt to explain the reason for the parse error."
[reason]
(str "Expecting one of (" (apply str (map #(str (:expecting %) " ") reason)) ")"))
(defn- parser-error-to-map
[parser-error]
(let [m (reduce (fn [map item](merge map {(first item)(second item)})) {} parser-error)
reason (map
#(reduce (fn [map item] (merge {(first item) (second item)} map)) {} %)
(:reason m))]
(merge m {:reason reason})))
(defn throw-parse-exception
"Construct a helpful error message from this `parser-error`, and throw an exception with that message."
[parser-error]
(assert (coll? parser-error) "Expected a paser error structure?")
(let
[
;; the error structure is a list, such that each element is a list of two items, and
;; the first element in each sublist is a keyword. Easier to work with it as a map
error-map (parser-error-to-map parser-error)
text (:text error-map)
reason (explain-parse-error-reason (:reason error-map))
;; rules have only one line, by definition; we're interested in the column
column (if (:column error-map)(:column error-map) 0)
;; create a cursor to point to that column
cursor (apply str (reverse (conj (repeat column " ") "^")))
message (format bad-parse-error text cursor reason)
]
(throw (Exception. message))))

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src/mw_parser/generate.clj Normal file
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(ns mw-parser.generate
(:use mw-engine.utils
mw-parser.utils
[mw-parser.errors :as pe]))
(declare generate generate-action)
(defn generate-rule
"From this `tree`, assumed to be a syntactically correct rule specification,
generate and return the appropriate rule as a function of two arguments."
[tree]
(assert-type tree :RULE)
(list 'fn ['cell 'world] (list 'if (generate (nth tree 2)) (generate (nth tree 3)))))
(defn generate-conditions
"From this `tree`, assumed to be a syntactically correct conditions clause,
generate and return the appropriate clojure fragment."
[tree]
(assert-type tree :CONDITIONS)
(generate (second tree)))
(defn generate-condition
[tree]
(assert-type tree :CONDITION)
(generate (second tree)))
(defn generate-conjunct-condition
[tree]
(assert-type tree :CONJUNCT-CONDITION)
(cons 'and (map generate (rest tree))))
(defn generate-disjunct-condition
[tree]
(assert-type tree :DISJUNCT-CONDITION)
(cons 'or (map generate (rest tree))))
(defn generate-ranged-property-condition
"Generate a property condition where the expression is a numeric range"
[tree property expression]
(assert-type tree :PROPERTY-CONDITION)
(assert-type (nth tree 3) :RANGE-EXPRESSION)
(let [l1 (generate (nth expression 2))
l2 (generate (nth expression 4))
pv (list property 'cell)]
(list 'let ['lower (list 'min l1 l2)
'upper (list 'max l1 l2)]
(list 'and (list '>= pv 'lower)(list '<= pv 'upper)))))
(defn generate-disjunct-property-condition
"Generate a property condition where the expression is a disjunct expression.
TODO: this is definitely still wrong!"
([tree]
(let [property (generate (second tree))
qualifier (generate (nth tree 2))
expression (generate (nth tree 3))]
(generate-disjunct-property-condition tree property qualifier expression)))
([tree property qualifier expression]
(let [e (list 'some (list 'fn ['i] '(= i value)) (list 'quote expression))]
(list 'let ['value (list property 'cell)]
(if (= qualifier '=) e
(list 'not e))))))
(defn generate-property-condition
([tree]
(assert-type tree :PROPERTY-CONDITION)
(if
(and (= (count tree) 2) (= (first (second tree)) :SYMBOL))
;; it's a shorthand for 'state equal to symbol'. This should probably have
;; been handled in simplify...
(generate-property-condition
(list
:PROPERTY-CONDITION
'(:SYMBOL "state")
'(:QUALIFIER (:EQUIVALENCE (:EQUAL "equal to")))
(second tree)))
;; otherwise...
(generate-property-condition tree (first (nth tree 3)))))
([tree expression-type]
(assert-type tree :PROPERTY-CONDITION)
(let [property (generate (second tree))
qualifier (generate (nth tree 2))
e (generate (nth tree 3))
expression (cond
(and (not (= qualifier '=)) (keyword? e)) (list 'or (list e 'cell) e)
(and (not (= qualifier 'not=)) (keyword? e)) (list 'or (list e 'cell) e)
:else e)]
(case expression-type
:DISJUNCT-EXPRESSION (generate-disjunct-property-condition tree property qualifier expression)
:RANGE-EXPRESSION (generate-ranged-property-condition tree property expression)
(list qualifier (list property 'cell) expression)))))
(defn generate-qualifier
[tree]
(if
(= (count tree) 2)
(generate (second tree))
;; else
(generate (nth tree 2))))
(defn generate-simple-action
([tree]
(assert-type tree :SIMPLE-ACTION)
(generate-simple-action tree []))
([tree others]
(assert-type tree :SIMPLE-ACTION)
(let [property (generate (second tree))
expression (generate (nth tree 3))]
(if (or (= property :x) (= property :y))
(throw (Exception. pe/reserved-properties-error))
(list 'merge
(if (empty? others) 'cell
;; else
(generate others))
{property expression})))))
(defn generate-probable-action
([tree]
(assert-type tree :PROBABLE-ACTION)
(generate-probable-action tree []))
([tree others]
(assert-type tree :PROBABLE-ACTION)
(let
[chances (generate (nth tree 1))
total (generate (nth tree 2))
action (generate-action (nth tree 3) others)]
;; TODO: could almost certainly be done better with macro syntax
(list 'if
(list '< (list 'rand total) chances)
action))))
(defn generate-action
[tree others]
(case (first tree)
:ACTIONS (generate-action (first tree) others)
:SIMPLE-ACTION (generate-simple-action tree others)
:PROBABLE-ACTION (generate-probable-action tree others)
(throw (Exception. (str "Not a known action type: " (first tree))))))
(defn generate-multiple-actions
[tree]
(assert-type tree :ACTIONS)
(generate-action (first (rest tree)) (second (rest tree))))
(defn generate-disjunct-value
"Generate a disjunct value. Essentially what we need here is to generate a
flat list of values, since the `member` has already been taken care of."
[tree]
(assert-type tree :DISJUNCT-VALUE)
(if (= (count tree) 4)
(cons (generate (second tree)) (generate (nth tree 3)))
(list (generate (second tree)))))
(defn generate-numeric-expression
[tree]
(assert-type tree :NUMERIC-EXPRESSION)
(case (count tree)
4 (let [[p operator expression] (rest tree)
property (if (number? p) p (list p 'cell))]
(list (generate operator) (generate property) (generate expression)))
(case (first (second tree))
:SYMBOL (list (keyword (second (second tree))) 'cell)
(generate (second tree)))))
(defn generate-neighbours-condition
"Generate code for a condition which refers to neighbours."
([tree]
(assert-type tree :NEIGHBOURS-CONDITION)
(case (first (second tree))
:QUANTIFIER (generate-neighbours-condition tree (first (second (second tree))))
:QUALIFIER (cons (generate (second tree)) (rest (generate (nth tree 2))))))
([tree quantifier-type]
(let [quantifier (second tree)
pc (generate (nth tree 4))]
(case quantifier-type
:NUMBER (generate-neighbours-condition '= (read-string (second (second quantifier))) pc 1)
:SOME (generate-neighbours-condition '> 0 pc 1)
:MORE (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '> value pc 1))
:LESS (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '< value pc 1))
)))
([comp1 quantity property-condition distance]
(list comp1
(list 'count
(list 'remove 'false?
(list 'map (list 'fn ['cell] property-condition)
(list 'mw-engine.utils/get-neighbours 'world 'cell distance)))) quantity))
([comp1 quantity property-condition]
(generate-neighbours-condition comp1 quantity property-condition 1)))
(defn generate-within-condition
"Generate code for a condition which refers to neighbours within a specified distance.
NOTE THAT there's clearly masses of commonality between this and
`generate-neighbours-condition`, and that some refactoring is almost certainly
desirable. It may be that it's better to simplify a `NEIGHBOURS-CONDITION`
into a `WITHIN-CONDITION` in the simplification stage."
([tree]
(assert-type tree :WITHIN-CONDITION)
(case (first (second tree))
:QUANTIFIER (generate-within-condition tree (first (second (second tree))))
:QUALIFIER (TODO "qualified within... help!")))
([tree quantifier-type]
(let [quantifier (second tree)
distance (generate (nth tree 4))
pc (generate (nth tree 6))]
(case quantifier-type
:NUMBER (generate-neighbours-condition '= (read-string (second (second quantifier))) pc distance)
:SOME (generate-neighbours-condition '> 0 pc distance)
:MORE (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '> value pc distance))
:LESS (let [value (generate (nth quantifier 3))]
(generate-neighbours-condition '< value pc distance))
))))
(defn generate
"Generate code for this (fragment of a) parse tree"
[tree]
(if
(coll? tree)
(case (first tree)
:ACTIONS (generate-multiple-actions tree)
:COMPARATIVE (generate (second tree))
:COMPARATIVE-QUALIFIER (generate (second tree))
:CONDITION (generate-condition tree)
:CONDITIONS (generate-conditions tree)
:CONJUNCT-CONDITION (generate-conjunct-condition tree)
:DISJUNCT-CONDITION (generate-disjunct-condition tree)
:DISJUNCT-EXPRESSION (generate (nth tree 2))
:DISJUNCT-VALUE (generate-disjunct-value tree)
:EQUIVALENCE '=
:EXPRESSION (generate (second tree))
:LESS '<
:MORE '>
:NEGATED-QUALIFIER (case (generate (second tree))
= 'not=
> '<
< '>)
:NEIGHBOURS-CONDITION (generate-neighbours-condition tree)
:NUMERIC-EXPRESSION (generate-numeric-expression tree)
:NUMBER (read-string (second tree))
:OPERATOR (symbol (second tree))
:PROBABLE-ACTION (generate-probable-action tree)
:PROPERTY (list (generate (second tree)) 'cell) ;; dubious - may not be right
:PROPERTY-CONDITION (generate-property-condition tree)
:QUALIFIER (generate-qualifier tree)
:RULE (generate-rule tree)
:SIMPLE-ACTION (generate-simple-action tree)
:SYMBOL (keyword (second tree))
:VALUE (generate (second tree))
:WITHIN-CONDITION (generate-within-condition tree)
(map generate tree))
tree))

48
src/mw_parser/simplify.clj Normal file
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@ -0,0 +1,48 @@
(ns mw-parser.simplify
(:use mw-engine.utils
mw-parser.utils))
(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 (second tree)) tree))
(defn simplify
"Simplify/canonicalise this `tree`. Opportunistically replace complex fragments with
semantically identical simpler fragments"
[tree]
(if
(coll? tree)
(case (first tree)
:ACTION (simplify-second-of-two tree)
:ACTIONS (cons (first tree) (simplify (rest tree)))
:CHANCE-IN nil
:COMPARATIVE (simplify-second-of-two tree)
:CONDITION (simplify-second-of-two tree)
:CONDITIONS (simplify-second-of-two tree)
:EXPRESSION (simplify-second-of-two tree)
:PROPERTY (simplify-second-of-two tree)
:PROPERTY-CONDITION-OR-EXPRESSION (simplify-second-of-two tree)
:SPACE nil
:THEN nil
:AND nil
:VALUE (simplify-second-of-two tree)
(remove nil? (map simplify tree)))
tree))

39
src/mw_parser/utils.clj Normal file
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@ -0,0 +1,39 @@
(ns mw-parser.utils)
(defn rule?
"Return true if the argument appears to be a parsed rule tree, else false."
[maybe-rule]
(and (coll? maybe-rule) (= (first maybe-rule) :RULE)))
(defn TODO
"Marker to indicate I'm not yet finished!"
[message]
message)
(defn suitable-fragment?
"Return `true` if `tree-fragment` appears to be a tree fragment of the expected `type`."
[tree-fragment type]
(and (coll? tree-fragment)
(= (first tree-fragment) type)))
(defn assert-type
"If `tree-fragment` is not a tree fragment of the expected `type`, throw an exception."
[tree-fragment type]
(assert (suitable-fragment? tree-fragment type)
(throw (Exception. (format "Expected a %s fragment" type)))))
(defn search-tree
"Return the first element of this tree which has this tag in a depth-first, left-to-right search"
[tree tag]
(cond
(= (first tree) tag) tree
:else (first
(remove nil?
(map
#(search-tree % tag)
(rest tree))))))

53
test/mw_parser/declarative_test.clj
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@ -2,7 +2,8 @@
(:use clojure.pprint
mw-engine.core
mw-engine.world
mw-engine.utils)
mw-engine.utils
mw-parser.utils)
(:require [clojure.test :refer :all]
[mw-parser.declarative :refer :all]))
@ -32,55 +33,6 @@
(is (rule? (parse-rule "if 6 neighbours have state equal to water then state should be village")))
))
(deftest expressions-tests
(testing "Generating primitive expressions."
(is (generate '(:NUMERIC-EXPRESSION (:NUMBER "50"))) 50)
(is (generate '(:NUMERIC-EXPRESSION (:SYMBOL "sealevel")))
'(:sealevel cell))
))
(deftest comparative-tests
(testing "Parsing comparatives."
))
(deftest lhs-generators-tests
(testing "Generating left-hand-side fragments of rule functions from appropriate fragments of parse trees"
(is (generate
'(:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")))
'(= (:state cell) :forest))
(is (generate
'(:PROPERTY-CONDITION (:SYMBOL "fertility") [:EQUIVALENCE [:IS "is"]] (:NUMBER "10")))
'(= (:fertility cell) 10))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "fertility") [:COMPARATIVE [:LESS "less"]] (:NUMBER "10")))
'(< (:fertility cell) 10))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "fertility") [:COMPARATIVE [:MORE "more"]] (:NUMBER "10")))
'(> (:fertility cell) 10))
(is (generate '(:CONJUNCT-CONDITION (:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")) (:AND "and") (:PROPERTY-CONDITION (:SYMBOL "fertility") [:EQUIVALENCE [:IS "is"]] (:NUMBER "10"))))
'(and (= (:state cell) :forest) (= (:fertility cell) 10)))
(is (generate '(:DISJUNCT-CONDITION (:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")) (:OR "or") (:PROPERTY-CONDITION (:SYMBOL "fertility") [:EQUIVALENCE [:IS "is"]] (:NUMBER "10"))))
'(or (= (:state cell) :forest) (= (:fertility cell) 10)))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:DISJUNCT-EXPRESSION (:IN "in") (:DISJUNCT-VALUE (:SYMBOL "grassland") (:OR "or") (:DISJUNCT-VALUE (:SYMBOL "pasture") (:OR "or") (:DISJUNCT-VALUE (:SYMBOL "heath")))))))
'(let [value (:state cell)] (some (fn [i] (= i value)) (quote (:grassland :pasture :heath)))))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "altitude") [:EQUIVALENCE [:IS "is"]] (:RANGE-EXPRESSION (:BETWEEN "between") (:NUMERIC-EXPRESSION (:NUMBER "50")) (:AND "and") (:NUMERIC-EXPRESSION (:NUMBER "100")))))
'(let [lower (min 50 100) upper (max 50 100)] (and (>= (:altitude cell) lower) (<= (:altitude cell) upper))))
))
(deftest rhs-generators-tests
(testing "Generating right-hand-side fragments of rule functions from appropriate fragments of parse trees"
(is (generate
'(:SIMPLE-ACTION (:SYMBOL "state") (:BECOMES "should be") (:SYMBOL "climax")))
'(merge cell {:state :climax}))
(is (generate
'(:SIMPLE-ACTION (:SYMBOL "fertility") (:BECOMES "should be") (:NUMBER "10")))
'(merge cell {:fertility 10}))
))
(deftest full-generation-tests
(testing "Full rule generation from pre-parsed tree"
(is (generate '(:RULE (:IF "if") (:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")) (:SIMPLE-ACTION (:SYMBOL "state") (:BECOMES "should be") (:SYMBOL "climax"))))
'(fn [cell world] (if (= (:state cell) :forest) (merge cell {:state :climax}))))
))
(deftest exception-tests
(testing "Constructions which should cause exceptions to be thrown"
@ -100,6 +52,7 @@
"Exception thrown on attempt to set 'y'")
))
(deftest correctness-tests
;; these are, in so far as possible, the same as the correctness-tests in core-tests - i.e., the two compilers
;; compile the same language.

57
test/mw_parser/generate_test.clj Normal file
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@ -0,0 +1,57 @@
(ns mw-parser.generate-test
(:use clojure.pprint
mw-engine.core
mw-engine.world
mw-engine.utils
mw-parser.utils)
(:require [clojure.test :refer :all]
[mw-parser.generate :refer :all]))
(deftest expressions-tests
(testing "Generating primitive expressions."
(is (generate '(:NUMERIC-EXPRESSION (:NUMBER "50"))) 50)
(is (generate '(:NUMERIC-EXPRESSION (:SYMBOL "sealevel")))
'(:sealevel cell))
))
(deftest lhs-generators-tests
(testing "Generating left-hand-side fragments of rule functions from appropriate fragments of parse trees"
(is (generate
'(:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")))
'(= (:state cell) :forest))
(is (generate
'(:PROPERTY-CONDITION (:SYMBOL "fertility") [:EQUIVALENCE [:IS "is"]] (:NUMBER "10")))
'(= (:fertility cell) 10))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "fertility") [:COMPARATIVE [:LESS "less"]] (:NUMBER "10")))
'(< (:fertility cell) 10))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "fertility") [:COMPARATIVE [:MORE "more"]] (:NUMBER "10")))
'(> (:fertility cell) 10))
(is (generate '(:CONJUNCT-CONDITION (:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")) (:AND "and") (:PROPERTY-CONDITION (:SYMBOL "fertility") [:EQUIVALENCE [:IS "is"]] (:NUMBER "10"))))
'(and (= (:state cell) :forest) (= (:fertility cell) 10)))
(is (generate '(:DISJUNCT-CONDITION (:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")) (:OR "or") (:PROPERTY-CONDITION (:SYMBOL "fertility") [:EQUIVALENCE [:IS "is"]] (:NUMBER "10"))))
'(or (= (:state cell) :forest) (= (:fertility cell) 10)))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:DISJUNCT-EXPRESSION (:IN "in") (:DISJUNCT-VALUE (:SYMBOL "grassland") (:OR "or") (:DISJUNCT-VALUE (:SYMBOL "pasture") (:OR "or") (:DISJUNCT-VALUE (:SYMBOL "heath")))))))
'(let [value (:state cell)] (some (fn [i] (= i value)) (quote (:grassland :pasture :heath)))))
(is (generate '(:PROPERTY-CONDITION (:SYMBOL "altitude") [:EQUIVALENCE [:IS "is"]] (:RANGE-EXPRESSION (:BETWEEN "between") (:NUMERIC-EXPRESSION (:NUMBER "50")) (:AND "and") (:NUMERIC-EXPRESSION (:NUMBER "100")))))
'(let [lower (min 50 100) upper (max 50 100)] (and (>= (:altitude cell) lower) (<= (:altitude cell) upper))))
))
(deftest rhs-generators-tests
(testing "Generating right-hand-side fragments of rule functions from appropriate fragments of parse trees"
(is (generate
'(:SIMPLE-ACTION (:SYMBOL "state") (:BECOMES "should be") (:SYMBOL "climax")))
'(merge cell {:state :climax}))
(is (generate
'(:SIMPLE-ACTION (:SYMBOL "fertility") (:BECOMES "should be") (:NUMBER "10")))
'(merge cell {:fertility 10}))
))
(deftest full-generation-tests
(testing "Full rule generation from pre-parsed tree"
(is (generate '(:RULE (:IF "if") (:PROPERTY-CONDITION (:SYMBOL "state") [:EQUIVALENCE [:IS "is"]] (:SYMBOL "forest")) (:SIMPLE-ACTION (:SYMBOL "state") (:BECOMES "should be") (:SYMBOL "climax"))))
'(fn [cell world] (if (= (:state cell) :forest) (merge cell {:state :climax}))))
))