For Next Loop usage Problem

[tianchao]

Dear:
I am a rookie on avisynth.
I want to process a video clip by 16x16 or 32x32 blocks. Basic idea is crop it, and then Stackhorizontal/StackVertical the blocks. When I use ForNext loop, the error is """script error: there is no function named "fornext" """.
Could anyone help me with this problem? Thanks.

[hanfrunz]

there is no for next loop in plain avisynth. But i think there is an external filter that can add this feature. :search:

[Gavino]

See GScript.

[tianchao]

thanks a lot, it is very helpful.