+(defun %clsql-subclauses (clauses)
+ "a helper for dealing with lists of sql clauses"
+ (loop for c in clauses
+ when c
+ collect (typecase c
+ (string (clsql-sys:sql-expression :string c))
+ (T c))))
+
+(defun clsql-ands (clauses)
+ "Correctly creates a sql 'and' expression for the clauses
+ ignores any nil clauses
+ returns a single child expression if there is only one
+ returns an 'and' expression if there are many
+ returns nil if there are no children"
+ (let ((ex (%clsql-subclauses clauses)))
+ (when ex
+ (case (length ex)
+ (1 (first ex))
+ (t (apply #'clsql-sys:sql-and ex))))))
+
+(defun clsql-and (&rest clauses)
+ "Correctly creates a sql 'and' expression for the clauses
+ ignores any nil clauses
+ returns a single child expression if there is only one
+ returns an 'and' expression if there are many
+ returns nil if there are no children"
+ (clsql-ands clauses))
+
+(defun clsql-ors (clauses)
+ "Correctly creates a sql 'or' expression for the clauses
+ ignores any nil clauses
+ returns a single child expression if there is only one
+ returns an 'or' expression if there are many
+ returns nil if there are no children"
+ (let ((ex (%clsql-subclauses clauses)))
+ (when ex
+ (case (length ex)
+ (1 (first ex))
+ (t (apply #'clsql-sys:sql-or ex))))))
+
+(defun clsql-or (&rest clauses)
+ "Correctly creates a sql 'or' expression for the clauses
+ ignores any nil clauses
+ returns a single child expression if there is only one
+ returns an 'or' expression if there are many
+ returns nil if there are no children"
+ (clsql-ors clauses))
+
+
+(defclass sql-escape-string-exp (%sql-expression)
+ ((string
+ :initarg :string
+ :initform nil))
+ (:documentation
+ "An escaped string string expression (postgresql E'stuff') ."))
+
+(defmethod output-sql ((exp sql-escape-string-exp) database)
+ (with-slots (string) exp
+ (when string
+ (write-char #\E *sql-stream*)
+ (output-sql string database))))