implement math, tweak syntax

waltz/macros.fnl

@@ -5,7 +5,9 @@
 (fn clause [c]
   (match c
     (where [:hashfn expr] (list? c)) `[:const ,expr]
-    (where [name & params] (list? c)) `[:literal ,(tostring name) ,(icollect [_ param (ipairs params)] (clause param))]
+    (where [name & params] (sequence? c)) `[:literal ,(tostring name) ,(icollect [_ param (ipairs params)] (clause param))]
+    (where [head & args] (list? c) (sym? head)) (icollect [_ expr (ipairs args) :into [(tostring head)]] (clause expr))
+    (where c (list? c)) (icollect [_ val (ipairs c)] (clause val))
     (where v (sym? c)) `[:var ,(tostring v)]
     _ `[:const ,c]))
 

waltz/sqlog.fnl

@@ -19,37 +19,39 @@
 ; case and build up from there.
 
 ; simple queries:
-; (p x y) -> SELECT p.c1 AS x, p.c2 AS y FROM p
-; (p 1 y) -> SELECT p.c2 AS y FROM p WHERE p.c1 = 1
-; (q x) (p x 1) -> SELECT q.c1 AS x FROM q JOIN p WHERE p.c1 = q.c1 AND p.c2 = 1
-; (p 1 2) -> SELECT true FROM p WHERE p.c1 = 1 AND p.c2 = 2
-; (p 1 x) (p x 2) -> SELECT t1.c2 AS x FROM p AS t1 JOIN p AS t2 WHERE t1.c1 = 1 AND t1.c2 = t2.c1 AND t2.c2 = 2
+; [p x y] -> SELECT p.c1 AS x, p.c2 AS y FROM p
+; [p 1 y] -> SELECT p.c2 AS y FROM p WHERE p.c1 = 1
+; [q x] [p x 1] -> SELECT q.c1 AS x FROM q JOIN p WHERE p.c1 = q.c1 AND p.c2 = 1
+; [p 1 2] -> SELECT true FROM p WHERE p.c1 = 1 AND p.c2 = 2
+; [p 1 x] [p x 2] -> SELECT t1.c2 AS x FROM p AS t1 JOIN p AS t2 WHERE t1.c1 = 1 AND t1.c2 = t2.c1 AND t2.c2 = 2
 
 ; queries using rules:
-; [(ancestor x y) (parent x y)] -> SELECT p.c1 AS x, p.c2 AS y FROM parent AS p
-; [(ancestor x y) (parent x z) (ancestor z y)] -> SELECT p.c1 AS x, a.y AS y FROM parent AS p JOIN ancestor AS a WHERE p.c1 = a.x AND p.c2 = a.y
-; (ancestor x :john) -> WITH RECURSIVE ancestor(x, y) AS (SELECT ... UNION SELECT ...) SELECT a.c1 AS x FROM ancestor AS a WHERE a.y = 'john'
-; [(ancestor :bob x) (ancestor x :john)] -> SELECT 'bob' AS c1, a.c1 AS c2 FROM ancestor AS a WHERE a.c2 = 'john'
+; ([ancestor x y] [parent x y]) -> SELECT p.c1 AS x, p.c2 AS y FROM parent AS p
+; ([ancestor x y] [parent x z] [ancestor z y]) -> SELECT p.c1 AS x, a.y AS y FROM parent AS p JOIN ancestor AS a WHERE p.c1 = a.x AND p.c2 = a.y
+; [ancestor x :john] -> WITH RECURSIVE ancestor(x, y) AS (SELECT ... UNION SELECT ...) SELECT a.c1 AS x FROM ancestor AS a WHERE a.y = 'john'
+; ([ancestor :bob x] [ancestor x :john]) -> SELECT 'bob' AS c1, a.c1 AS c2 FROM ancestor AS a WHERE a.c2 = 'john'
 
-; queries with comparisons? arithmetic operations? function calls?
-; (p x y) (< x 5) -> SELECT p.c1 AS x, p.c2 AS y FROM p WHERE p.c1 < 5
-; (p x y) (q (+ x 1)) -> SELECT p.c1 AS x, p.c2 AS y FROM p JOIN q WHERE q.c1 = p.c1 + 1
-; (p (+ x 1) y) (q x) -> SELECT q.c1 AS x, p.c2 AS y FROM p JOIN q WHERE p.c1 + 1 = q.c1
-; (p (+ x 1) x) -> SELECT p.c2 AS x FROM p WHERE p.c1 + 1 = p.c2
+; queries with arithmetic operations (function calls?)
+; [p x y] [q (+ x 1)] -> SELECT p.c1 AS x, p.c2 AS y FROM p JOIN q WHERE q.c1 = p.c1 + 1
+; [p (+ x 1) y] [q x] -> SELECT q.c1 AS x, p.c2 AS y FROM p JOIN q WHERE p.c1 = q.c1 + 1
+; [p (+ x 1) x] -> SELECT p.c2 AS x FROM p WHERE p.c1 = p.c2 + 1
+
+; queries with comparisons
+; [p x y] (< x 5) -> SELECT p.c1 AS x, p.c2 AS y FROM p WHERE p.c1 < 5
 
 ; confusing expressions we probably won't support:
-; (p (+ x 1) (* x 2)) -> SELECT p.c1 - 1 AS x FROM p WHERE p.c1 + 1 = p.c2 * 2??
+; [p (+ x 1) (* x 2)] -> SELECT p.c1 - 1 AS x FROM p WHERE p.c1 + 1 = p.c2 * 2??
 ; no, that's not right - this says x+1 = c1 AND x*2 = c2
-; (p (+ x 1) (* x 2)) -> SELECT p.c1 - 1 AS x FROM p WHERE p.c2 = (p.c1 - 1) * 2
-  ; (p (+ x 1) y) -> meaningless? or...
+; [p (+ x 1) (* x 2)] -> SELECT p.c1 - 1 AS x FROM p WHERE p.c2 = (p.c1 - 1) * 2
+; [p (+ x 1) y] -> meaningless? or...
 ;               -> SELECT p.c1 - 1 AS x, p.c2 AS y FROM p
 ; is there a way to trick sql into generating x = p.c1 - 1 from p.c1 = x + 1?
-; (p z y) (= z (+ x 1))
+; [p z y] (= z (+ x 1))
 
 ; unsupported: inline comparisons, explicit equality checks (use unification instead)
-; (p (< x 5) y) -> SELECT p.c1 AS x, p.c2 AS y FROM p WHERE p.c1 < 5 -- does this make sense? seems hard to read, hard to parse
-; (p x y) (= x y) -> unnecessary, can be written (p x x)
-; (p x y) (= x (+ y 1)) -> unnecessary, can be written (p (+ x 1) x)?
+; [p (< x 5) y] -> SELECT p.c1 AS x, p.c2 AS y FROM p WHERE p.c1 < 5 -- does this make sense? seems hard to read, hard to parse
+; [p x y] (= x y) -> unnecessary, can be written (p x x)
+; [p x y] (= x (+ y 1)) -> unnecessary, can be written (p (+ x 1) x)?
 
 (fn Sqlog.new [self]
   (set self.tables {})
@@ -97,6 +99,7 @@
                                (match value
                                  [:var varname] (self:reference-variable analysis varname [:column itable icolumn])
                                  [:const val]   (add-clause analysis [:= [:column itable icolumn] [:const val]])
+                                 [op & args]    (add-clause analysis [:= [:column itable icolumn] value])
                                  _ (error (.. "expected var or const, got " (fv value))))))
     _ (error (.. "Expected literal but got " (fv literal)))))
 
@@ -109,6 +112,7 @@
    :constants (or (?. ?parent :constants) [])
    :referenced-rules (or (?. ?parent :referenced-rules) [])})
 
+(local infix-ops (collect [_ op (ipairs [:+ :- :* :/ :< :> :<= :>= := :|| :and :or])] op true))
 (fn Sqlog.gen-expr [self analysis expr]
   (match expr
     [:const val] (do (table.insert analysis.constants val) "?")
@@ -117,7 +121,8 @@
                                    colnames (. colnames icolumn)
                                    _        (.. "c" icolumn)))
     [:as subexpr name] (.. (self:gen-expr analysis subexpr) " AS " name)
-    [:= lhs rhs] (.. (self:gen-expr analysis lhs) " = " (self:gen-expr analysis rhs))
+    (where [:var name] (. analysis.variable-mapping name)) (self:gen-expr analysis (. analysis.variable-mapping name))
+    (where [op lhs rhs] (. infix-ops op)) (.. (self:gen-expr analysis lhs) " " op " " (self:gen-expr analysis rhs))
     _ (error (.. "Unrecognized expression " (fv expr)))))
 
 (fn cat [list sep ?f]

waltz/sqltest.fnl

@@ -3,8 +3,10 @@
 
 (local s (Sqlog))
 (s:deftable :parent :parent :child)
+(s:deftable :p :x :y)
+(s:deftable :q :z)
 (defrules s
-  [(ancestor x y) (parent x y)]
-  [(ancestor x y) (parent x z) (ancestor z y)])
-(pp (query s (ancestor x y)))
+  ([ancestor x y] [parent x y])
+  ([ancestor x y] [parent x z] [ancestor z y]))
+(pp (query s [p x y] [q (+ x 1)]))