/// <summary>
/// Tries to get the <see cref="L20nCore.Objects.Entity"/> instance based on the stored reference (name)
/// and will return the evaluation result of the looked up object if possible.
/// Returns <c>null</c> in case the object could not be found or the evaluation
/// of the looked up object returned <c>null</c> itself.
/// </summary>
public override L20nObject Eval(LocaleContext ctx, params L20nObject[] argv)
{
var entity = ctx.GetEntity(m_Identifier);
if (entity == null)
{
return entity;
}
return entity.Eval(ctx, argv);
}
/// <summary>
/// Evaluate all the expressions contained in this <see cref="L20nCore.Objects.StringValue"/>
/// and use the results of these evaluations as the variables used in the evaluation
/// of the format string to compute the final result value as a <see cref="L20nCore.Objects.StringOutput"/>.
/// </summary>
public override L20nObject Eval(LocaleContext ctx, params L20nObject[] argv)
{
// Evaluate each expression and store them in the cached list
for (int i = 0; i < m_EvaluatedExpressions.Length; ++i)
{
var e = m_Expressions [i].Eval(ctx);
// if one cannot evaluate, we can't know the real final result
// and thus we return early
if (e == null)
{
return null;
}
// Identifiers get evaluated until we get a non-reference value
Identifier id;
Entity entity;
while ((id = e as Identifier) != null)
{
entity = ctx.GetEntity(id.Value);
if (entity != null)
e = entity.Eval(ctx);
}
var primitive = e as Primitive;
// in the end we expect to be left with a primitive value,
// if not there is something wrong in the global evaluation logic.
if (primitive == null)
{
Logger.WarningFormat("<StringValue>: couldn't evaluate expression #{0}", i);
return null;
}
// we expect a primitive value so that we can turn it into a string
var stringOutput = primitive.ToString(ctx);
if (stringOutput == null)
{
Logger.WarningFormat("<StringValue>: couldn't evaluate expression #{0} to <StringOutput>", i);
return null;
}
m_EvaluatedExpressions [i] = stringOutput;
}
// we update the cached StringOutput value and return it as
// the result of this evaluation.
m_Output.Value = FormatString(m_Value, m_EvaluatedExpressions);
return m_Output;
}
/// <summary>
/// A help function to get the entity based on the first variable.
/// The given identifier is either an Identifier, Variable or Global,
/// which will define the action to be taken in order to get and return the Root Entity.
/// </summary>
private Entity GetEntity(LocaleContext ctx)
{
// is it an identifier?
var identifier = m_Root as Identifier;
if (identifier != null)
return ctx.GetEntity(identifier.Value);
// is it a string?
var str = m_Root.Eval(ctx) as StringOutput;
if (str != null)
return ctx.GetEntity(str.Value);
// is it a variable?
var variable = m_Root as Variable;
if (variable != null)
return ctx.GetVariable(variable.Identifier) as Entity;
// is it a global?
var global = m_Root as Global;
if (global != null)
return ctx.GetGlobal(global.Identifier) as Entity;
return null;
}
/// <summary>
/// A help function to get the root entity based on the first variable.
/// The given identifier is either an Identifier, Variable or Global,
/// which will define the action to be taken in order to get and return the Root Entity.
/// </summary>
private Entity GetEntity(LocaleContext ctx, L20nObject key)
{
// is it an identifier?
var identifier = key as Identifier;
if (identifier != null)
return ctx.GetEntity(identifier.Value);
// is it a variable?
var variable = key as Variable;
if (variable != null)
{
var obj = ctx.GetVariable(variable.Identifier);
// a variable can also be a string-reference to an entity
var reference = obj as StringOutput;
if (reference != null)
{
return ctx.GetEntity(reference.Value);
}
// otherwise it's simply an entity (or at least it should be)
return obj as Entity;
}
// is it a global?
var global = key as Global;
if (global != null)
return ctx.GetGlobal(global.Identifier) as Entity;
// is it a string?
var str = key as StringOutput;
if (str != null)
return ctx.GetEntity(str.Value);
return null;
}
