Preserve the type information by creating a new list in which the type code precedes each value. The sender might have code like this:
list a = [ ... some series of values ];
list b = encodeList(a);
llSay( commChannel, llDumpList2String( [ "listData", llGetListLength(b) ]
encodeList(b) + ["END"] , "|" );
The receiver might have code like this
listen( integer channel, string fromName, key fromKey, string msg ) {
if ( channel == commChannel ) {
list f = llParseStringKeepNulls( msg, "|" );
if ( "listData" == llList2String(f,0) ) {
if ( "END" != llList2String(f,-1) ) {
... tell some that the message has been truncated
} else {
integer n = (integer) llList2String(f,1);
list dataList = [];
if ( n > 0 ) {
dataList = decode( llList2List( f, 2, 1 + n );
}
n = llGetListLength(dataList);
........
}
}
}
}
The encoder logic might be this
list typeList = [TYPE_FLOAT, TYPE_INTEGER, TYPE_KEY,
TYPE_ROTATION, TYPE_STRING, TYPE_VECTOR ];
list encodeTypeList( list a ) {
list b = [];
integer n = llGetListLength(a);
integer k; for ( k=0; k < n; k++ ) {
integer type = llGetListEntryType(a,k);
integer type = llGetListEntryType(a,k);
integer match = llListFindList( typeList, [type] );
if ( match >= 0 ) {
b += [type] + llList2List(a,k,k);
} else llOwnerSay("** failed to match list entry type: "+(string)type);
}
return b;
}
The decoder logic might be this:
list decodeTypeList( list a ) {
list b = [];
integer n = llGetListLength(a);
integer k; for ( k=0; k < n; k += 2 ) {
integer type = (integer) llList2String(a,k);
integer type = (integer) llList2String(a,k);
string svalue = llList2String(a,k+1);
integer match = llListFindList( typeList, [type] );
if ( match >= 0 ) {
if ( match-- == 0 ) b += (float) svalue;
if ( match-- == 0 ) b += (integer) svalue;
if ( match-- == 0 ) b += (key) svalue;
if ( match-- == 0 ) b += (rotation) svalue;
if ( match-- == 0 ) b += svalue;
if ( match-- == 0 ) b += (vector) svalue;
}
}
return b;
}
__________________
Notes:
- When sending variable length lists, append "END" to the end of the message and have the receiver verify that it is still there. There is a limit to the length of messages.
- Include the encoded list length in the message, so that the receiver can extract the list.
- Since lists may have zero length, the receiver should handle the zero length case.
[end]
