GIMP: ReplaceInFile

I don't know if it's like this for all the PortableApps.com Apps, but this is what i found in part of the GIMP ReplaceInFile file.

IfFileExists $2 +1 RIF_error ; knock-knock
FileOpen $R0 $2 "r" ; open the door

GetTempFileName $R2 ; who's new?
FileOpen $R1 $R2 "w" ; the escape, please!

RIF_loop: ; round'n'round we go
FileRead $R0 $R3 ; read one line
IfErrors RIF_leaveloop ; enough is enough
RIF_sar: ; sar - search and replace
Push "$R3" ; (hair)stack
Push "$1" ; needle
Push "$0" ; blood
Call StrReplace ; do the bartwalk
StrCpy $R4 "$R3" ; remember previous state
Pop $R3 ; gimme s.th. back in return!
StrCmp "$R3" "$R4" +1 RIF_sar ; loop, might change again!
FileWrite $R1 "$R3" ; save the newbie
Goto RIF_loop ; gimme more

RIF_leaveloop: ; over'n'out, Sir!
FileClose $R1 ; S'rry, Ma'am - clos'n now
FileClose $R0 ; me 2

Delete "$2.old" ; go away, Sire
Rename "$2" "$2.old" ; step aside, Ma'am
Rename "$R2" "$2" ; hi, baby!

ClearErrors ; now i AM a newborn
Goto RIF_out ; out'n'away

RIF_error: ; ups - s.th. went wrong...
SetErrors ; ...so cry, boy!

RIF_out: ; your wardrobe?

Haha, what?