The set commands assign the value provided to the member.
The commands with the "var" suffix are used to access custom members for a struct, which are really just that ID's gamevars which have the per-<struct> flag set. So
setactorvar[THISACTOR].temp 0 is the same as
setvar temp 0.
|actor||sprite id||Yes||sprites and hittypes||You can use THISACTOR as the id for current sprite.|
|tspr||sprite id||No||sprites' display properties||Can only be used within EVENT_ANIMATESPRITES on sprites with mdflags containing flag 16.|
You can use THISACTOR as the id for current sprite.
|projectile||tile number||No||projectile types|
|thisprojectile||sprite id||No||individual projectiles||You can use THISACTOR as the id for current sprite.|
|sector||sector id||No||sectors, floors, and ceilings||You can use THISACTOR as the sector id for the sector in which the current actor is in.|
|player||player id||Yes||players||The player id is usually THISACTOR, but screenpeek and myconnectindex are technically possible.|
|input||player id||No||input||Can only be used within EVENT_PROCESSINPUT.|
The player id is usually provided by THISACTOR. It is unknown whether other values are useful or applicable.
|userdef||(none)||No||user preferences||Use THISACTOR for the id.|