New parser now well advanced, parses all but one of the test rules.

However code generation only just started.

src/mw_parser/insta.clj

@@ -6,27 +6,143 @@
 
 (def grammar
   "RULE := 'if' SPACE CONDITIONS SPACE 'then' SPACE ACTIONS;
-   CONDITIONS := CONDITION | CONDITION SPACE 'and' SPACE CONDITIONS;
+   CONDITIONS := DISJUNCT-CONDITION | CONJUNCT-CONDITION | PROPERTY-CONDITION | NEIGHBOURS-CONDITION ;
-   CONDITION := DISJUNCT-CONDITION | PROPERTY-CONDITION;
+   DISJUNCT-CONDITION := CONDITION SPACE 'or' SPACE CONDITIONS;
-   DISJUNCT-CONDITION := CONDITION SPACE 'or' SPACE CONDITION;
+   CONJUNCT-CONDITION := CONDITION SPACE 'and' SPACE CONDITIONS;
-   PROPERTY-CONDITION := PROPERTY SPACE 'is' SPACE EXPRESSION;
+   CONDITION := NEIGHBOURS-CONDITION | PROPERTY-CONDITION;
-   EXPRESSION := VALUE QUALIFIER EXPRESSION | VALUE OPERATOR EXPRESSION | VALUE;
+   NEIGHBOURS-CONDITION := QUANTIFIER SPACE NEIGHBOURS SPACE IS SPACE PROPERTY-CONDITION | QUANTIFIER SPACE NEIGHBOURS IS EXPRESSION | QUALIFIER SPACE NEIGHBOURS-CONDITION;
-   QUALIFIER := SPACE 'more' SPACE 'than' SPACE | SPACE 'less' SPACE 'than' SPACE | SPACE 'fewer' SPACE 'than' SPACE | SPACE 'equal' SPACE 'to' SPACE ;
+   PROPERTY-CONDITION := PROPERTY SPACE QUALIFIER SPACE EXPRESSION;
+   EXPRESSION := SIMPLE-EXPRESSION | RANGE-EXPRESSION | NUMERIC-EXPRESSION | DISJUNCT-EXPRESSION | VALUE;
+   SIMPLE-EXPRESSION := QUALIFIER SPACE EXPRESSION | VALUE;
+   DISJUNCT-EXPRESSION := 'in' SPACE DISJUNCT-VALUE;
+   RANGE-EXPRESSION := 'between' SPACE NUMERIC-EXPRESSION SPACE 'and' SPACE NUMERIC-EXPRESSION;
+   NUMERIC-EXPRESSION := VALUE | VALUE SPACE OPERATOR SPACE NUMERIC-EXPRESSION;
+   QUALIFIER := COMPARATIVE SPACE 'than' | EQUIVALENCE | IS SPACE QUALIFIER;
+   NEIGHBOURS := 'neighbour' | 'neighbor' | 'neighbours' | 'neighbors';
+   QUANTIFIER := NUMBER | 'some' | 'no' | 'all';
+   EQUIVALENCE := IS SPACE 'equal to' | 'equal to' | IS ;
+   COMPARATIVE := 'more' | 'less' | 'fewer';
    OPERATOR := '+' | '-' | '*' | '/';
    PROPERTY := SYMBOL;
+   DISJUNCT-VALUE := VALUE | VALUE SPACE 'or' SPACE DISJUNCT-VALUE;
    VALUE := SYMBOL | NUMBER;
-   NUMBER := #'[0-9.]+';
+   IS := 'is' | 'are' | 'have';
+   NUMBER := #'[0-9]+' | #'[0-9]+.[0-9]+';
    SYMBOL := #'[a-z]+';
    ACTIONS := ACTION | ACTION SPACE 'and' SPACE ACTIONS
-   ACTION := SYMBOL SPACE 'should' SPACE 'be' SPACE EXPRESSION
+   ACTION := SIMPLE-ACTION | PROBABLE-ACTION;
-   SPACE := #'[:blank:]*'"
+   PROBABLE-ACTION := VALUE SPACE 'chance in' SPACE VALUE SPACE SIMPLE-ACTION;
+   SIMPLE-ACTION := SYMBOL SPACE 'should be' SPACE EXPRESSION
+   SPACE := #' *'"
   )
 
+(defn TODO
+  "Marker to indicate I'm not yet finished!"
+  [message]
+  message)
+
+
+(declare generate)
+
+(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]
+  (let [left (generate (nth tree 2))
+        right (generate (nth tree 4))]
+    (list 'fn ['cell 'world] (list 'if left right))))
+
+(defn generate-conditions
+  "From this `tree`, assumed to be a syntactically correct conditions clause,
+  generate and return the appropriate clojure fragment."
+  [tree]
+  (generate (nth tree 1)))
+
+(defn generate-condition
+  [tree]
+  (generate (nth tree 1)))
+
+(defn generate-conjunct-condition
+  [tree]
+  (list 'and (generate (nth tree 1))(generate (nth tree 3))))
+
+(defn generate-disjunct-condition
+  [tree]
+  (list 'or (generate (nth tree 1))(generate (nth tree 3))))
+
+(defn generate-qualifier
+  "Return more than (>), less than (<) or equal to (=) depending on the `qualifier`."
+  [qualifier]
+  (TODO "not written yet")
+  tree)
+
+
+(defn generate-property-condition
+  [tree]
+  (let [property (generate (nth tree 1))
+        qualifier (generate (nth tree 2))
+        expression (generate (nth tree 3))]
+    (list qualifier (list (keyword property) 'cell) expression)))
+
+
+(defn generate
+  "Generate code for this (fragment of a) parse tree"
+  [tree]
+  (case (first tree)
+    :RULE (generate-rule tree)
+    :CONDITIONS (generate-conditions tree)
+    :CONDITION (generate-condition tree)
+;;    :NEIGHBOURS-CONDITION (generate-neighbours-condition tree)
+    :DISJUNCT-CONDITION (generate-disjunct-condition tree)
+    :CONJUNCT-CONDITION (generate-conjunct-condition tree)
+    :PROPERTY-CONDITION (generate-property-condition tree)
+;;    :EXPRESSION (generate-expression tree)
+;;    :SIMPLE-EXPRESSION
+    tree))
+
+(defn prune-tree
+  "Simplify/canonicalise the `tree`. Opportunistically replace complex fragments with
+  semantically identical simpler fragments"
+  [tree]
+  (TODO "not written yet")
+  tree)
+
+(defn clean-tree
+  "Returns a structure which is structurally equivalent to `tree` but which has
+  the noise tokens (spaces) removed. As a side effect this new structure is a
+  list, not a vector, but that is not a desideratum and you should not rely in it."
+  [tree]
+  (cond
+   (and (coll? tree) (= (first tree) :SPACE)) nil
+   (coll? tree) (remove nil? (map clean-tree tree))
+   true tree))
+
 (def rule-parser
   (insta/parser grammar))
 
-(def token-parser (insta/parser "TOKEN := #'[a-z]+'"))
+(defn compile-rule [rule]
+  (generate (prune-tree (clean-tree (rule-parser rule)))))
 
 
 
 
+(compile-rule "if state is climax and some neighbours have state equal to fire then 3 chance in 5 state should be fire")
+
+
+(rule-parser "if state is in grassland or pasture or heath and 4 neighbours have state equal to water then state should be village")
+
+(rule-parser "if 6 neighbours have state equal to water then state should be village")
+
+(rule-parser "if fertility is between 55 and 75 then state should be climax")
+
+(rule-parser "if state is forest then state should be climax")
+
+
+(rule-parser "if state is in grassland or pasture or heath and 4 neighbours have state equal to water then state should be village")
+(rule-parser "if altitude is less than 100 and state is forest then state should be climax and deer should be 3")
+(rule-parser "if altitude is 100 or fertility is 25 then state should be heath and fertility should be 24.3")
+(rule-parser "if altitude is 100 or fertility is 25 then state should be heath")
+
+(rule-parser "if deer is more than 2 and wolves is 0 and fertility is more than 20 then deer should be deer + 2")
+(rule-parser "if deer is more than 1 and wolves is more than 1 then deer should be deer - wolves")
+(rule-parser "if state is grassland and 4 neighbours have state equal to water then state should be village")