query: fix #:cross joins

deta-doc/deta.scrbl

@@ -730,10 +730,10 @@ queries.
 
 @defform*[
   #:literals (subquery unquote)
-  ((join query maybe-type maybe-lateral table-name #:as alias #:on q-expr)
-   (join query maybe-type maybe-lateral schema-id #:as alias #:on q-expr)
-   (join query maybe-type maybe-lateral (subquery query) #:as alias #:on q-expr)
-   (join query maybe-type maybe-lateral (unquote table-name-expr) #:as alias #:on q-expr))
+  ((join query maybe-type maybe-lateral table-name #:as alias maybe-condition)
+   (join query maybe-type maybe-lateral schema-id #:as alias maybe-condition)
+   (join query maybe-type maybe-lateral (subquery query) #:as alias maybe-condition)
+   (join query maybe-type maybe-lateral (unquote table-name-expr) #:as alias maybe-condition))
   #:grammar
   ([maybe-type (code:line)
                (code:line #:inner)
@@ -742,13 +742,16 @@ queries.
                (code:line #:full)
                (code:line #:cross)]
    [maybe-lateral (code:line)
-                  (code:line #:lateral)])
+                  (code:line #:lateral)]
+   [maybe-condition (code:line)
+                    (code:line #:on q-expr)])
   #:contracts
   ([table-name non-empty-string?]
    [query query?])]{
 
-  Adds a @tt{JOIN} to @racket[query].  If a join type is not provided,
-  then the join defaults to an @tt{INNER} join.
+  Adds a @tt{JOIN} to @racket[query]. If a join type is not provided,
+  then the join defaults to an @tt{INNER} join. A join condition is
+  required for all join types apart from @racket[#:cross].
 
   @interaction[
     #:eval reference-eval

deta-lib/info.rkt

@@ -1,7 +1,7 @@
 #lang info
 
 (define license 'BSD-3-Clause)
-(define version "0.15")
+(define version "0.15.1")
 (define collection "deta")
 
 (define deps '("base"

deta-lib/private/dialect/standard.rkt

@@ -306,8 +306,9 @@
      (when lateral?
        (write-string "LATERAL "))
      (write-expr with)
-     (write-string " ON ")
-     (write-expr constraint)]
+     (unless (eq? type 'cross)
+       (write-string " ON ")
+       (write-expr constraint))]
 
     [(where e)
      (write-string "WHERE ")

deta-lib/private/query.rkt

@@ -89,7 +89,7 @@
        #:lateral? boolean?
        #:with (or/c ast:subquery? schema? string? symbol?)
        #:as symbol?
-       #:on ast:expr?
+       #:on (or/c #f ast:expr?)
        query?)]
   [limit (-> query? (or/c ast:scalar? ast:placeholder?) query?)]
   [offset (-> query? (or/c ast:scalar? ast:placeholder?) query?)]
@@ -99,8 +99,8 @@
   [project-virtual-fields (-> query? query?)]
   [returning (-> query? ast:expr? ast:expr? ... query?)]
   [select
-   (->* (query? ast:expr?)
-        (#:distinct? boolean?)
+   (->* [query? ast:expr?]
+        [#:distinct? boolean?]
         #:rest (listof ast:expr?)
         query?)]
   [select-for-schema

deta-lib/query.rkt

@@ -474,16 +474,27 @@
      #'(dyn:group-by q e.e ...)]))
 
 (define-syntax (join stx)
-  (define-syntax-class join-type
+  (define-syntax-class qualified-join-type
     (pattern #:inner #:with type #''inner)
     (pattern #:left  #:with type #''left)
     (pattern #:right #:with type #''right)
-    (pattern #:full  #:with type #''full)
-    (pattern #:cross #:with type #''cross))
+    (pattern #:full  #:with type #''full))
 
   (syntax-parse stx
     [(_ q:expr
-        (~optional t:join-type)
+        #:cross
+        (~optional (~and #:lateral lateral))
+        source:q-source
+        #:as alias:id)
+     #:with lateral? (if (attribute lateral) #'#t #'#f)
+     #'(dyn:join q
+                 #:type 'cross
+                 #:lateral? lateral?
+                 #:with source.e
+                 #:as 'alias
+                 #:on #f)]
+    [(_ q:expr
+        (~optional t:qualified-join-type)
         (~optional (~and #:lateral lateral))
         source:q-source
         #:as alias:id

deta-test/deta/sql-postgresql.rkt

@@ -354,7 +354,27 @@
                   #:as pi
                   #:on #t)
             (select p.* pi.*))
-        "SELECT p.*, pi.* FROM posts AS p LEFT JOIN LATERAL (SELECT * FROM post_images AS pi WHERE pi.post_id = p.id ORDER BY pi.id DESC LIMIT 1) AS pi ON TRUE")))
+        "SELECT p.*, pi.* FROM posts AS p LEFT JOIN LATERAL (SELECT * FROM post_images AS pi WHERE pi.post_id = p.id ORDER BY pi.id DESC LIMIT 1) AS pi ON TRUE"))
+
+     (test-case "emits cross joins"
+       (check-emitted
+        (~> (from "posts" #:as p)
+            (join #:cross "post_images" #:as pi)
+            (select p.* pi.*))
+        "SELECT p.*, pi.* FROM posts AS p CROSS JOIN post_images AS pi"))
+
+     (test-case "emits cross lateral joins"
+       (check-emitted
+        (~> (from "posts" #:as p)
+            (join #:cross
+                  #:lateral
+                  (subquery
+                   (~> (from "post_images" #:as pi)
+                       (where (= pi.post-id p.id))
+                       (limit 1)))
+                  #:as pi)
+            (select p.*))
+        "SELECT p.* FROM posts AS p CROSS JOIN LATERAL (SELECT * FROM post_images AS pi WHERE pi.post_id = p.id LIMIT 1) AS pi")))
 
     (test-suite
      "group-by"