/// <summary>
/// Read parse trees from a Reader.
/// </summary>
/// <param name="input">The Reader</param>
/// <param name="tf">TreeFactory -- factory to create some kind of Tree</param>
/// <param name="tn">the method of normalizing trees</param>
/// <param name="st">Tokenizer that divides up Reader</param>
public PennTreeReader(TextReader input, ITreeFactory tf, TreeNormalizer tn, ITokenizer <string> st)
{
reader = input;
treeFactory = tf;
treeNormalizer = tn;
tokenizer = st;
// check for whacked out headers still present in Brown corpus in Treebank 3
string first = (st.HasNext() ? st.Peek() : null);
if (first != null && first.StartsWith("*x*x*x"))
{
int foundCount = 0;
while (foundCount < 4 && st.HasNext())
{
first = st.Next();
if (first != null && first.StartsWith("*x*x*x"))
{
foundCount++;
}
}
}
}
/// <summary>
/// Reads a single tree in standard Penn Treebank format from the
/// input stream. The method supports additional parentheses around the
/// tree (an unnamed ROOT node) so long as they are balanced. If the token stream
/// ends before the current tree is complete, then the method will throw an
/// <code>IOException</code>.
///
/// Note that the method will skip malformed trees and attempt to
/// read additional trees from the input stream. It is possible, however,
/// that a malformed tree will corrupt the token stream. In this case,
/// an <code>IOException</code> will eventually be thrown.
/// </summary>
/// <returns>A single tree, or <code>null</code> at end of token stream.</returns>
public Tree ReadTree()
{
Tree t = null;
while (tokenizer.HasNext() && t == null)
{
//Setup PDA
this.currentTree = null;
this.stack = new List <Tree>();
try
{
t = GetTreeFromInputStream();
}
catch (Exception e)
{
throw new IOException("End of token stream encountered before parsing could complete.");
}
if (t != null)
{
// cdm 20100618: Don't do this! This was never the historical behavior!!!
// Escape empty trees e.g. (())
// while(t != null && (t.value() == null || t.value().equals("")) && t.numChildren() <= 1)
// t = t.firstChild();
if (treeNormalizer != null && treeFactory != null)
{
t = treeNormalizer.NormalizeWholeTree(t, treeFactory);
}
t.IndexLeaves(true);
}
}
return(t);
}
/// <summary>
/// Read parse trees from a Reader.
/// </summary>
/// <param name="input">The Reader</param>
/// <param name="tf">TreeFactory -- factory to create some kind of Tree</param>
/// <param name="tn">the method of normalizing trees</param>
/// <param name="st">Tokenizer that divides up Reader</param>
public PennTreeReader(TextReader input, ITreeFactory tf, TreeNormalizer tn, ITokenizer<string> st)
{
reader = input;
treeFactory = tf;
treeNormalizer = tn;
tokenizer = st;
// check for whacked out headers still present in Brown corpus in Treebank 3
string first = (st.HasNext() ? st.Peek() : null);
if (first != null && first.StartsWith("*x*x*x"))
{
int foundCount = 0;
while (foundCount < 4 && st.HasNext())
{
first = st.Next();
if (first != null && first.StartsWith("*x*x*x"))
{
foundCount++;
}
}
}
}
