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fgdata/Nasal/props.nas
2012-10-13 15:20:27 +02:00

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##
# Node class definition. The class methods simply wrap the
# low level extension 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.
#
var Node = {
getNode : func wrap(_getNode(me._g, arg)),
getParent : func wrap(_getParent(me._g, arg)),
getChild : func wrap(_getChild(me._g, arg)),
getChildren : func wrap(_getChildren(me._g, arg)),
addChild : func wrap(_addChild(me._g, arg)),
removeChild : func wrap(_removeChild(me._g, arg)),
removeChildren : func wrap(_removeChildren(me._g, arg)),
getAliasTarget : func wrap(_getAliasTarget(me._g, arg)),
getName : func _getName(me._g, arg),
getIndex : func _getIndex(me._g, arg),
getType : func _getType(me._g, arg),
getAttribute : func _getAttribute(me._g, arg),
setAttribute : func _setAttribute(me._g, arg),
getValue : func _getValue(me._g, arg),
setValue : func _setValue(me._g, arg),
setIntValue : func _setIntValue(me._g, arg),
setBoolValue : func _setBoolValue(me._g, arg),
setDoubleValue : func _setDoubleValue(me._g, arg),
unalias : func _unalias(me._g, arg),
alias : func(n) _alias(me._g, [isa(n, Node) ? n._g : n]),
clearValue : func _alias(me._g, [_globals()]) and me.unalias(),
getPath : func {
var (name, index, parent) = (me.getName(), me.getIndex(), me.getParent());
if(index != 0) { name ~= "[" ~ index ~ "]"; }
if(parent != nil) { name = parent.getPath() ~ "/" ~ name; }
return name;
},
getBoolValue : func {
var val = me.getValue();
var mytype = me.getType();
if((mytype == "STRING" or mytype == "UNSPECIFIED") and val == "false") return 0;
return !!val;
},
remove : func {
if((var p = me.getParent()) == nil) return nil;
p.removeChild(me.getName(), me.getIndex());
},
};
##
# Static constructor for a Node object. Accepts a Nasal hash
# expression to initialize the object a-la setValues().
#
Node.new = func(values = nil) {
var result = wrapNode(_new());
if(typeof(values) == "hash")
result.setValues(values);
return result;
}
##
# Useful utility. Sets a whole property tree from a Nasal hash
# object, such that scalars become leafs in the property tree, hashes
# become named subnodes, and vectors become indexed subnodes. This
# works recursively, so you can define whole property trees with
# syntax like:
#
# dialog = {
# name : "exit", width : 180, height : 100, modal : 0,
# text : { x : 10, y : 70, label : "Hello World!" } };
#
Node.setValues = func(val) {
foreach(var k; keys(val)) { me._setChildren(k, val[k]); }
}
##
# Private function to do the work of setValues().
# The first argument is a child name, the second a nasal scalar,
# vector, or hash.
#
Node._setChildren = func(name, val) {
var subnode = me.getNode(name, 1);
if(typeof(val) == "scalar") { subnode.setValue(val); }
elsif(typeof(val) == "hash") { subnode.setValues(val); }
elsif(typeof(val) == "vector") {
for(var i=0; i<size(val); i+=1) {
var iname = name ~ "[" ~ i ~ "]";
me._setChildren(iname, val[i]);
}
}
}
##
# Counter piece of setValues(). Returns a hash with all values
# in the subtree. Nodes with same name are returned as vector,
# where the original node indices are lost. The function should
# only be used if all or almost all values are needed, and never
# in performance-critical code paths. If it's called on a node
# without children, then the result is equivalent to getValue().
#
Node.getValues = func {
var children = me.getChildren();
if(!size(children)) return me.getValue();
var val = {};
var numchld = {};
foreach(var c; children) {
var name = c.getName();
if(contains(numchld, name)) { var nc = numchld[name]; }
else {
var nc = size(me.getChildren(name));
numchld[name] = nc;
if(nc > 1 and !contains(val, name)) val[name] = [];
}
if(nc > 1) append(val[name], c.getValues());
else val[name] = c.getValues();
}
return val;
}
##
# Initializes property if it's still undefined. First argument
# is a property name/path. It can also be nil or an empty string,
# in which case the node itself gets initialized, rather than one
# of its children. Second argument is the default value. The third,
# optional argument is a property type (one of "STRING", "DOUBLE",
# "INT", or "BOOL"). If it is omitted, then "DOUBLE" is used for
# numbers, and STRING for everything else. Returns the property
# as props.Node. The fourth optional argument enforces a type if
# non-zero.
#
Node.initNode = func(path = nil, value = 0, type = nil, force = 0) {
var prop = me.getNode(path or "", 1);
if(prop.getType() != "NONE") value = prop.getValue();
if(force) prop.clearValue();
if(type == nil) prop.setValue(value);
elsif(type == "DOUBLE") prop.setDoubleValue(value);
elsif(type == "INT") prop.setIntValue(value);
elsif(type == "BOOL") prop.setBoolValue(value);
elsif(type == "STRING") prop.setValue("" ~ value);
else die("initNode(): unsupported type '" ~ type ~ "'");
return prop;
}
##
# 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.
#
var 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); }
}
}
##
# Recursively copy property branch from source Node to
# destination Node. Doesn't copy aliases. Copies attributes
# if optional third argument is set and non-zero.
#
var copy = func(src, dest, attr = 0) {
foreach(var c; src.getChildren()) {
var name = c.getName() ~ "[" ~ c.getIndex() ~ "]";
copy(src.getNode(name), dest.getNode(name, 1), attr);
}
var type = src.getType();
var val = src.getValue();
if(type == "ALIAS" or type == "NONE") return;
elsif(type == "BOOL") dest.setBoolValue(val);
elsif(type == "INT" or type == "LONG") dest.setIntValue(val);
elsif(type == "FLOAT" or type == "DOUBLE") dest.setDoubleValue(val);
else dest.setValue(val);
if(attr) dest.setAttribute(src.getAttribute());
}
##
# Utility. Turns any ghosts it finds (either solo, or in an
# array) into Node objects.
#
var wrap = func(node) {
var argtype = typeof(node);
if(argtype == "ghost") {
return wrapNode(node);
} elsif(argtype == "vector") {
var v = node;
var n = size(v);
for(var i=0; i<n; i+=1) { v[i] = wrapNode(v[i]); }
return v;
}
return node;
}
##
# 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. :)
#
var wrapNode = func(node) { { parents : [Node], _g : node } }
##
# 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.
#
var globals = wrapNode(_globals());
##
# Sets all indexed property children to a single value. arg[0]
# specifies a property name (e.g. /controls/engines/engine), arg[1] a
# path under each node of that name to set (e.g. "throttle"), arg[2]
# is the value.
#
var setAll = func(base, child, value) {
var node = props.globals.getNode(base);
if(node == nil) return;
var name = node.getName();
node = node.getParent();
if(node == nil) return;
var children = node.getChildren();
foreach(var c; children)
if(c.getName() == name)
c.getNode(child, 1).setValue(value);
}
##
# Turns about anything into a list of props.Nodes, including ghosts,
# path strings, vectors or hashes containing, as well as functions
# returning any of the former and in arbitrary nesting. This is meant
# to be used in functions whose main purpose is to handle collections
# of properties.
#
var nodeList = func {
var list = [];
foreach(var a; arg) {
var t = typeof(a);
if(isa(a, Node))
append(list, a);
elsif(t == "scalar")
append(list, props.globals.getNode(a, 1));
elsif(t == "vector")
foreach(var i; a)
list ~= nodeList(i);
elsif(t == "hash")
foreach(var i; keys(a))
list ~= nodeList(a[i]);
elsif(t == "func")
list ~= nodeList(a());
elsif(t == "ghost" and ghosttype(a) == "prop")
append(list, wrapNode(a));
else
die("nodeList: invalid nil property");
}
return list;
}
##
# Evaluates a <condition> property branch according to the rules
# set out in $FG_ROOT/Docs/README.conditions. Undefined conditions
# and a nil argument are "true". The function dumps the condition
# branch and returns nil on error.
#
var condition = func(p) {
if(p == nil) return 1;
if(!isa(p, Node)) p = props.globals.getNode(p);
return _cond_and(p)
}
var _cond_and = func(p) {
foreach(var c; p.getChildren())
if(!_cond(c)) return 0;
return 1;
}
var _cond_or = func(p) {
foreach(var c; p.getChildren())
if(_cond(c)) return 1;
return 0;
}
var _cond = func(p) {
var n = p.getName();
if(n == "or") return _cond_or(p);
if(n == "and") return _cond_and(p);
if(n == "not") return !_cond_and(p);
if(n == "equals") return _cond_cmp(p, 0);
if(n == "not-equals") return !_cond_cmp(p, 0);
if(n == "less-than") return _cond_cmp(p, -1);
if(n == "greater-than") return _cond_cmp(p, 1);
if(n == "less-than-equals") return !_cond_cmp(p, 1);
if(n == "greater-than-equals") return !_cond_cmp(p, -1);
if(n == "property") return !!getprop(p.getValue());
printlog("alert", "condition: invalid operator ", n);
dump(p);
return nil;
}
var _cond_cmp = func(p, op) {
var left = p.getChild("property", 0, 0);
if(left != nil) { left = getprop(left.getValue()); }
else {
printlog("alert", "condition: no left value");
dump(p);
return nil;
}
var right = p.getChild("property", 1, 0);
if(right != nil) { right = getprop(right.getValue()); }
else {
right = p.getChild("value", 0, 0);
if(right != nil) { right = right.getValue(); }
else {
printlog("alert", "condition: no right value");
dump(p);
return nil;
}
}
if(left == nil or right == nil) {
printlog("alert", "condition: comparing with nil");
dump(p);
return nil;
}
if(op < 0) return left < right;
if(op > 0) return left > right;
return left == right;
}
##
# Runs <binding> as described in $FG_ROOT/Docs/README.commands using
# a given module by default, and returns 1 if fgcommand() succeeded,
# or 0 otherwise. The module name won't override a <module> defined
# in the binding.
#
var runBinding = func(node, module = nil) {
if(module != nil and node.getNode("module") == nil)
node.getNode("module", 1).setValue(module);
var cmd = node.getNode("command", 1).getValue() or "null";
condition(node.getNode("condition")) ? fgcommand(cmd, node) : 0;
}