[求助]：菜单格式的迷惑

chat_lin

我在看CAD自带的ACAD.MNU文件是有这些内容不了解：
***BUTTONS1
// Simple + button
// if a grip is hot bring up the Grips Cursor Menu (POP 500), else send a carriage return
// If the SHORTCUTMENU sysvar is not 0 the first item (for button 1) is NOT USED.
$M=$(if,$(eq,$(substr,$(getvar,cmdnames),1,5),GRIP_),$P0=ACAD.GRIPS $P0=*);
$P0=SNAP $p0=*
^C^C
^B
^O
^G
^D
^E
^T
还有：
***AUX1
// Simple button
// if a grip is hot bring up the Grips Cursor Menu (POP 500), else send a carriage return
// If the SHORTCUTMENU sysvar is not 0 the first item (for button 1, the "right button")
// is NOT USED.
$M=$(if,$(eq,$(substr,$(getvar,cmdnames),1,5),GRIP_),$P0=ACAD.GRIPS $P0=*);
$P0=SNAP $p0=*
^C^C
^B
^O
^G
^D
^E
^T
能不能讲一下这两种菜单相的作用呢