/// <summary>
/// To write out the value of a condition expr, we invoke the evaluator
/// in eval.g to walk the condition tree computing the boolean value.
/// If result is true, then we write subtemplate.
/// </summary>
public override int Write(StringTemplate self, IStringTemplateWriter output)
{
if (exprTree == null || self == null || output == null)
{
return 0;
}
// System.out.println("evaluating conditional tree: "+exprTree.toStringList());
ActionEvaluator eval = new ActionEvaluator(self, this, output);
ActionParser.initializeASTFactory(eval.getASTFactory());
int n = 0;
try
{
// get conditional from tree and compute result
AST cond = exprTree.getFirstChild();
bool includeSubtemplate = eval.ifCondition(cond); // eval and write out tree
// System.out.println("subtemplate "+subtemplate);
if (includeSubtemplate)
{
/* To evaluate the IF chunk, make a new instance whose enclosingInstance
* points at 'self' so get attribute works. Otherwise, enclosingInstance
* points at the template used to make the precompiled code. We need a
* new template instance every time we exec this chunk to get the new
* "enclosing instance" pointer.
*/
StringTemplate s = subtemplate.GetInstanceOf();
s.EnclosingInstance = self;
// make sure we evaluate in context of enclosing template's
// group so polymorphism works. :)
s.Group = self.Group;
s.NativeGroup = self.NativeGroup;
n = s.Write(output);
}
else if (elseSubtemplate != null)
{
// evaluate ELSE clause if present and IF condition failed
StringTemplate s = elseSubtemplate.GetInstanceOf();
s.EnclosingInstance = self;
s.Group = self.Group;
s.NativeGroup = self.NativeGroup;
n = s.Write(output);
}
}
catch (RecognitionException re)
{
self.Error("can't evaluate tree: " + exprTree.ToStringList(), re);
}
return n;
}
/// <summary>
/// Evaluate an argument list within the context of the enclosing
/// template but store the values in the context of self, the
/// new embedded template. For example, bold(item=item) means
/// that bold.item should get the value of enclosing.item.
/// </summary>
protected internal virtual void EvaluateArguments(StringTemplate self)
{
StringTemplateAST argumentsAST = self.ArgumentsAST;
if (argumentsAST == null || argumentsAST.getFirstChild() == null)
{
// return immediately if missing tree or no actual args
return ;
}
// Evaluate args in the context of the enclosing template, but we
// need the predefined args like 'it', 'attr', and 'i' to be
// available as well so we put a dummy ST between the enclosing
// context and the embedded context. The dummy has the predefined
// context as does the embedded.
StringTemplate enclosing = self.EnclosingInstance;
StringTemplate argContextST = new StringTemplate(self.Group, "");
argContextST.Name = "<invoke " + self.Name + " arg context>";
argContextST.EnclosingInstance = enclosing;
argContextST.ArgumentContext = self.ArgumentContext;
ActionEvaluator eval = new ActionEvaluator(argContextST, this, null);
ActionParser.initializeASTFactory(eval.getASTFactory());
/*
System.out.println("eval args: "+argumentsAST.toStringList());
System.out.println("ctx is "+self.getArgumentContext());
*/
try
{
// using any initial argument context (such as when obj is set),
// evaluate the arg list like bold(item=obj). Since we pass
// in any existing arg context, that context gets filled with
// new values. With bold(item=obj), context becomes:
// {[obj=...],[item=...]}.
IDictionary ac = eval.argList(argumentsAST, self, self.ArgumentContext);
self.ArgumentContext = ac;
}
catch (RecognitionException re)
{
self.Error("can't evaluate tree: " + argumentsAST.ToStringList(), re);
}
}
/// <summary>
/// An EXPR is normally just a string literal, but is still an AST that
/// we must evaluate. The EXPR can be any expression such as a template
/// include or string cat expression etc...
///
/// Evaluate with its own writer so that we can convert to string and then
/// reuse, don't want to compute all the time; must precompute w/o writing
/// to output buffer.
/// </summary>
protected internal string EvaluateExpression(StringTemplate self, object expr)
{
if (expr == null)
{
return null;
}
if (expr is StringTemplateAST)
{
StringTemplateAST exprTree = (StringTemplateAST) expr;
// must evaluate, writing to a string so we can hand on to it
StringWriter buf = new StringWriter();
IStringTemplateWriter sw = self.group.CreateInstanceOfTemplateWriter(buf);
ActionEvaluator eval = new ActionEvaluator(self, this, sw);
try
{
eval.action(exprTree); // eval tree
}
catch (RecognitionException ex)
{
self.Error("can't evaluate tree: " + exprTree.ToStringList(), ex);
}
return buf.ToString();
}
else
{
// just in case we expand in the future and it's something else
return expr.ToString();
}
}
/// <summary>
/// To write out the value of an ASTExpr, invoke the evaluator in eval.g
/// to walk the tree writing out the values. For efficiency, don't
/// compute a bunch of strings and then pack them together. Write out directly.
///
/// Compute separator and wrap expressions, save as strings so we don't
/// recompute for each value in a multi-valued attribute or expression.
///
/// If they set anchor option, then inform the writer to push current
/// char position.
/// </summary>
public override int Write(StringTemplate self, IStringTemplateWriter output)
{
if (exprTree == null || self == null || output == null)
{
return 0;
}
output.PushIndentation(Indentation);
// handle options, anchor, wrap, separator...
StringTemplateAST anchorAST = (StringTemplateAST)GetOption("anchor");
if (anchorAST != null) // any non-empty expr means true; check presence
{
output.PushAnchorPoint();
}
HandleExprOptions(self);
ActionEvaluator eval = new ActionEvaluator(self, this, output);
ActionParser.initializeASTFactory(eval.getASTFactory());
int n = 0;
try
{
n = eval.action(exprTree); // eval and write out tree
}
catch (RecognitionException re)
{
self.Error("can't evaluate tree: " + exprTree.ToStringList(), re);
}
output.PopIndentation();
if (anchorAST != null)
{
output.PopAnchorPoint();
}
return n;
}
