LookupIcon (iconname, size):
for each subdir in $(theme subdir list) {
    for each directory in $(basename list) {
        for extension in ("png", "svg", "xpm") {
            if DirectoryMatchesSize(subdir, size) {
                filename = directory/$(themename)/subdirectory/iconname.extension
                if exist filename
	            return filename
            }
	}
   }
}

minimal_size = MAXINT
for each subdir in $(theme subdir list) {
    for each directory in $(basename list) {
        for extension in ("png", "svg", "xpm") {
            filename = directory/$(themename)/subdirectory/iconname.extension
            if exist filename and DirectorySizeDistance(subdir, size) < minimal_size
	        closest_filename = filename
		minimal_size = DirectorySizeDistance(subdir, size)
	}
   }
}
if closest_filename set
   return closest_filename
   
for each directory in $(basename list) {
    for extension in ("png", "svg", "xpm") {
	if exists directory/iconname.extension
	   return directory/iconname.extension
    }
}

return failed icon lookup
     

[Icon Theme]
Name=Birch
Name[sv]=Björk
Comment=Icon theme with a wooden look
Comment[sv]=Träinspirerat ikontema
Inherits=wood,default
Directories=48x48/apps,48x48/mimetypes,32x32/apps,scalable/apps,scalable/mimetypes

[scalable/apps]
Size=48
Type=Scalable
MinSize=1
MaxSize=256
Context=Applications

[scalable/mimetypes]
Size=48
Type=Scalable
MinSize=1
MaxSize=256
Context=MimeTypes

[32x32/apps]
Size=32
Type=Fixed
Context=Applications

[48x48/apps]
Size=48
Type=Fixed
Context=Applications

[48x48/mimetypes]
Size=48
Type=Fixed
Context=MimeTypes