About errors of script-fu

1. Try to work not exist layers.

   Example

   (gimp-image-merge-visible-layers img 0)

   :

   (gimp-layer-resize layer1 width height 0 0)

   If layer1 was visible, layer1 merged and not exist, so it is an error.

2. Used wrong variable.

   Example

   (gimp-message a)

   If you wanna receive message a, it is "a", if you wanna watch the value of a, it is (number->string a).

3. Set impossible number of plugins.
4. After GIMP2.0, before (gimp-image-add-layer img layer1 0), change layer-size or add some plug-ins effects, it's an error. (Only GIMP1.2 can use this).
5. Used not declared variable.

   Example

   (gimp-layer-resize layer1 tate yoko 0 0)

   layer1, tate and yoko should declare.

   
   

   The right answer

   (let* (

       (yoko (car (gimp-drawable-width drawable)))

       (tate (car (gimp-drawable-height drawable)))

       (layer1 (car (gimp-layer-new img width height RGB_IMAGE "Background" 100 NORMAL)))

     )

   :

   :

   )

6. Not close bracket. I think this mistake many people did. If too much left bracket used, declared variable treated error, and if too much right bracket used, in script-fu menu scm name doesn't come out.
7. Declared variable is too few. Message is "too few arguments". If used plug-ins variable is too few, it's an error.
8. Syntax error. Message is "bad function".

   Example

   (if (= a 0) set! (a 1))

    

   The right answer

   (if (= a 0) (set! a 1))

9. About gimp2.6, if "Bad syntax of binding spec in let : (layer1)" showed, change (layer1) to (layer1 0).