branch: elpa/emacsql
commit 4a89bfaf4487d82429944fb35893e16680483417
Author: Christopher Wellons <[email protected]>
Commit: Christopher Wellons <[email protected]>
Use a macro to greatly simplify expanders.
---
emacsql.el | 78 ++++++++++++++++++++++++++++++++------------------------------
1 file changed, 40 insertions(+), 38 deletions(-)
diff --git a/emacsql.el b/emacsql.el
index dc27c69de1..ab39fa7c8d 100644
--- a/emacsql.el
+++ b/emacsql.el
@@ -355,53 +355,55 @@ KIND should be :value or :identifier."
(:identifier (emacsql-escape thing))
(otherwise thing))))
+(defvar emacsql--vars ()
+ "For use with `emacsql-with-vars'.")
+
+(defun emacsql-symbol-function (symbol)
+ "Like `symbol-function' but don't return an error."
+ (ignore-errors (symbol-function symbol)))
+
+(gv-define-setter emacsql-symbol-function (store symbol)
+ `(if ,store (fset ,symbol ,store) (fmakunbound ,symbol)))
+
+(defun emacsql--vars-collect (thing kind)
+ "Only use within `emacsql-with-vars'!"
+ (if (emacsql-var thing)
+ (prog1 "%s" (push (cons (emacsql-var thing) kind) emacsql--vars))
+ (ecase kind
+ ((:identifier :value) (emacsql-escape-format thing kind))
+ (:auto (emacsql-escape-format
+ thing (if (symbolp thing) :identifier :value))))))
+
+(defmacro emacsql-with-vars (prefix &rest body)
+ "Evaluate BODY, collecting variables with `var'.
+BODY should return a string, which will be combined with variable
+definitions for return from a `emacsql-defexpander'."
+ (declare (indent 1))
+ `(let ((emacsql--vars ()))
+ (cl-letf (((emacsql-symbol-function 'var)
+ (symbol-function 'emacsql--vars-collect)))
+ (cons (concat ,prefix (progn ,@body)) emacsql--vars))))
+
;; SQL Expansion Functions:
(emacsql-defexpander :select (arg)
"Expands to the SELECT keyword."
- (let ((vars ()))
- (cons
- (concat
- "SELECT "
- (cond
- ((eq '* arg) "*")
- ((emacsql-var arg)
- (push (cons (emacsql-var arg) :identifier) vars)
- "%s")
- ((symbolp arg)
- (emacsql-escape-format arg :identifier))
- ((vectorp arg)
- (mapconcat
- #'identity
- (cl-loop for name elements of arg
- when (emacsql-var name)
- collect (prog1 "%s" (push (cons it :identifier) vars))
- else when (symbolp name)
- collect (emacsql-escape-format name :identifier)
- else do (error "Unknown format %S" name))
- ", "))))
- (nreverse vars))))
+ (emacsql-with-vars "SELECT "
+ (cond
+ ((eq '* arg) "*")
+ ((vectorp arg)
+ (mapconcat (lambda (s) (var s :identifier)) arg ", "))
+ ((var arg :identifier)))))
(emacsql-defexpander :from (table)
"Expands to the FROM keyword."
- (if (emacsql-var table)
- (list "FROM %s" (cons (emacsql-var table) :identifier))
- (list (concat "FROM " (emacsql-escape-format table :identifier)))))
+ (emacsql-with-vars "FROM "
+ (var table :identifier)))
(emacsql-defexpander :where (expr)
- (let ((vars ()))
- (cl-flet* ((collect (thing)
- (push (cons (emacsql-var thing) :auto) vars) "%s")
- (handle (v)
- (cond ((emacsql-var v) (collect v))
- ((symbolp v) (emacsql-escape-format v :identifier))
- ((emacsql-escape-format v :value)))))
- (cl-destructuring-bind (op a b) expr
- (cons (format "WHERE %s %s %s"
- (handle a)
- op
- (handle b))
- (nreverse vars))))))
+ (emacsql-with-vars "WHERE "
+ (cl-destructuring-bind (op a b) expr
+ (format "%s %s %s" (var a :auto) op (var b :auto)))))
(provide 'emacsql)
