fragment program
<optLegacyTexUnitNum> ::= ""
| "[" <legacyTexUnitNum> "]"
-
-NOTE: <optLegaceTexUnitNum> is not optional.
*/
optLegacyTexUnitNum
+ optLegacyTexUnitNum_1 .or .true .emit 0x00;
+optLegacyTexUnitNum_1
lbracket_ne .and legacyTexUnitNum .and rbracket;
/*