commit 1c5e559f907c867fae6c09b7b09c5b347de8e7e0
parent 0d8907b5e851e084ed4fc420d00d69f67df16323
Author: septeql <septeql@telent.net>
Date: Tue, 7 Aug 2007 15:30:36 +0000
add translation for sql CASE
Diffstat:
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/septeql.lisp b/septeql.lisp
@@ -70,6 +70,21 @@ interpolated into a SQL statement as a string literal"
(define-scalar-translator as (column-expr alias)
(format nil "~A AS ~A" (translate-scalar column-expr) (lisp-to-sql-name alias)))
+(define-scalar-translator case (&rest clauses)
+ (with-output-to-string (o)
+ (princ "(CASE " o)
+ (loop for (expr result) in clauses
+ if (and (symbolp expr) (member expr '(t else) :test #'string-equal))
+ do (format o "ELSE ~A " (translate-scalar result))
+ else do (format o "WHEN ~A THEN ~A "
+ (translate-scalar expr)
+ (translate-scalar result)))
+ (princ "END) " o)))
+
+;; SQL's CASE is more like CL's COND, so define the latter as an alias
+(define-scalar-translator cond (&rest clauses)
+ (translate-scalar `(case ,@clauses)))
+
;;; we *could* use the zero-length symbol for string concatenation,
;;; relying on the printer to render it as ``||'', but that's arguably
;;; kinda tacky. So, ++ for sticking strings together
@@ -166,8 +181,6 @@ interpolated into a SQL statement as a string literal"
`(rename ,(sv sql 'from) ,name))
sql))))
-
-
(defun min~ (&rest args)
(let ((real-args (remove-if #'not args)))
(and (car real-args) (apply #'min real-args))))
@@ -208,7 +221,6 @@ interpolated into a SQL statement as a string literal"
(translate-scalar (fourth from))))
(t (error "buggered if I know"))))
-
(defun as-string (sql)
(with-output-to-string (s)
(format s "SELECT ~{~A~^,~} "
@@ -231,4 +243,3 @@ interpolated into a SQL statement as a string literal"
(defun to-sql (relation)
(as-string (parse-relation relation)))
-
