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fgdata/Nasal/props.nas
2003-12-02 17:54:15 +00:00

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##
# Node class definition. The class methods simply wrap the
# low level exention functions which work on a "ghost" handle to a
# SGPropertyNode object stored in the _g field.
#
# Not all of the features of SGPropertyNode are supported. There is
# no support for ties, obviously, as that wouldn't make much sense
# from a Nasal context. The various get/set methods work only on the
# local node, there is no equivalent of the "relative path" variants
# available in C++; just use node.getNode(path).whatever() instead.
# There is no support for the "listener" interface yet. The aliasing
# feature isn't exposed, except that you can get an "ALIAS" return
# from getType to detect them (to avoid cycles while walking the
# tree).
#
Node = {
getType : func { wrap(_getType(me._g, arg)) },
getName : func { wrap(_getName(me._g, arg)) },
getIndex : func { wrap(_getIndex(me._g, arg)) },
getValue : func { wrap(_getValue(me._g, arg)) },
setValue : func { wrap(_setValue(me._g, arg)) },
setIntValue : func { wrap(_setIntValue(me._g, arg)) },
setBoolValue : func { wrap(_setBoolValue(me._g, arg)) },
setDoubleValue : func { wrap(_setDoubleValue(me._g, arg)) },
getParent : func { wrap(_getParent(me._g, arg)) },
getChild : func { wrap(_getChild(me._g, arg)) },
getChildren : func { wrap(_getChildren(me._g, arg)) },
removeChild : func { wrap(_removeChild(me._g, arg)) },
getNode : func { wrap(_getNode(me._g, arg)) },
};
# Static constructor. Accepts a hash as an argument and duplicates
# its contents in the property node. ex:
# Node.new({ value : 1.0, units : "ms" });
Node.new = func {
result = wrapNode(_new());
if(typeof(arg[0]) == "hash") {
foreach(k; keys(arg[0])) {
result.getNode(k, 1).setValue(arg[0][k]);
}
}
}
##
# Useful debugging utility. Recursively dumps the full state of a
# Node object to the console. Try binding "props.dump(props.globals)"
# to a key for a fun hack.
#
dump = func {
if(size(arg) == 1) { prefix = ""; node = arg[0]; }
else { prefix = arg[0]; node = arg[1]; }
index = node.getIndex();
type = node.getType();
name = node.getName();
val = node.getValue();
if(val == nil) { val = "nil"; }
name = prefix ~ name;
if(index > 0) { name = name ~ "[" ~ index ~ "]"; }
print(name, " {", type, "} = ", val);
# Don't recurse into aliases, lest we get stuck in a loop
if(type != "ALIAS") {
children = node.getChildren();
foreach(c; children) { dump(name ~ "/", c); }
}
}
##
# Utility. Turns any ghosts it finds (either solo, or in an
# array) into Node objects.
#
wrap = func {
argtype = typeof(arg[0]);
if(argtype == "ghost") {
return wrapNode(arg[0]);
} elsif(argtype == "vector") {
v = arg[0];
n = size(v);
for(i=0; i<n; i=i+1) { v[i] = wrapNode(v[i]); }
return v;
}
return arg[0];
}
##
# Utility. Returns a new object with its superclass/parent set to the
# Node object and its _g (ghost) field set to the specified object.
# Nasal's literal syntax can be pleasingly terse. I like that. :)
#
wrapNode = func { { parents : [Node], _g : arg[0] } }
##
# Global property tree. Set once at initialization. Is that OK?
# Does anything ever call globals.set_props() from C++? May need to
# turn this into a function if so.
#
props.globals = wrapNode(_globals());