branch: elpa/emacsql
commit 109664b88b2920eb35bb5807e36dc342552e943d
Author: Christopher Wellons <well...@nullprogram.com>
Commit: Christopher Wellons <well...@nullprogram.com>
Memoize emacsql-expand.
---
emacsql.el | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/emacsql.el b/emacsql.el
index fb7e700120..e2c646d578 100644
--- a/emacsql.el
+++ b/emacsql.el
@@ -289,6 +289,9 @@ Each row must be a sequence of values to store into TABLE.
(defvar emacsql-expanders ()
"Alist of all expansion functions.")
+(defvar emacsql-expander-cache (make-hash-table :test 'equal)
+ "Cache used to memoize `emacsql-expand'.")
+
(defun emacsql-add-expander (keyword arity function)
"Register FUNCTION for KEYWORD as a SQL expander.
FUNCTION should accept the keyword's arguments and should return
@@ -296,6 +299,7 @@ a list of (<string> [arg-pos] ...).
See also `emacsql-with-errors'."
(prog1 keyword
+ (clrhash emacsql-expander-cache)
(push (list keyword arity function) emacsql-expanders)))
(defmacro emacsql-defexpander (keyword args &rest body)
@@ -305,16 +309,22 @@ See also `emacsql-with-errors'."
(defun emacsql-expand (sql)
"Expand SQL into a SQL-consumable string, with variables."
- (cl-loop with items = (cl-coerce sql 'list)
- while (not (null items))
- for keyword = (pop items)
- for (arity expander) = (cdr (assoc keyword emacsql-expanders))
- when expander
- collect (apply expander (cl-subseq items 0 arity)) into parts
- else do (error "Unrecognized keyword %s" keyword)
- do (setf items (cl-subseq items arity))
- finally (cl-return (cons (concat (mapconcat #'car parts " ") ";")
- (apply #'nconc (mapcar #'cdr parts))))))
+ (let* ((cache emacsql-expander-cache)
+ (cached (and cache (gethash sql cache))))
+ (or cached
+ (cl-loop with items = (cl-coerce sql 'list)
+ while (not (null items))
+ for keyword = (pop items)
+ for (arity expander) = (cdr (assoc keyword emacsql-expanders))
+ when expander
+ collect (apply expander (cl-subseq items 0 arity)) into parts
+ else do (error "Unrecognized keyword %s" keyword)
+ do (setf items (cl-subseq items arity))
+ finally
+ (let ((string (concat (mapconcat #'car parts " ") ";"))
+ (vars (apply #'nconc (mapcar #'cdr parts))))
+ (cl-return (setf (gethash sql cache)
+ (cons string vars))))))))
(defun emacsql-format (expansion &rest args)
"Fill in the variables EXPANSION with ARGS."
