/** <summary>
* Create a tree or node from the indicated tree pattern that closely
* follows ANTLR tree grammar tree element syntax:
*
* (root child1 ... child2).
* </summary>
*
* <remarks>
* You can also just pass in a node: ID
*
* Any node can have a text argument: ID[foo]
* (notice there are no quotes around foo--it's clear it's a string).
*
* nil is a special name meaning "give me a nil node". Useful for
* making lists: (nil A B C) is a list of A B C.
* </remarks>
*/
public virtual object Create(string pattern)
{
TreePatternLexer tokenizer = new TreePatternLexer(pattern);
TreePatternParser parser = new TreePatternParser(tokenizer, this, adaptor);
object t = parser.Pattern();
return(t);
}
/** <summary>
* Given a pattern like (ASSIGN %lhs:ID %rhs:.) with optional labels
* on the various nodes and '.' (dot) as the node/subtree wildcard,
* return true if the pattern matches and fill the labels Map with
* the labels pointing at the appropriate nodes. Return false if
* the pattern is malformed or the tree does not match.
* </summary>
*
* <remarks>
* If a node specifies a text arg in pattern, then that must match
* for that node in t.
*
* TODO: what's a better way to indicate bad pattern? Exceptions are a hassle
* </remarks>
*/
public bool Parse(object t, string pattern, IDictionary <string, object> labels)
{
TreePatternLexer tokenizer = new TreePatternLexer(pattern);
TreePatternParser parser =
new TreePatternParser(tokenizer, this, new TreePatternTreeAdaptor());
TreePattern tpattern = (TreePattern)parser.Pattern();
/*
* System.out.println("t="+((Tree)t).toStringTree());
* System.out.println("scant="+tpattern.toStringTree());
*/
bool matched = ParseCore(t, tpattern, labels);
return(matched);
}
/** <summary>
* For all subtrees that match the pattern, execute the visit action.
* The implementation uses the root node of the pattern in combination
* with visit(t, ttype, visitor) so nil-rooted patterns are not allowed.
* Patterns with wildcard roots are also not allowed.
* </summary>
*/
public void Visit(object t, string pattern, IContextVisitor visitor)
{
// Create a TreePattern from the pattern
TreePatternLexer tokenizer = new TreePatternLexer(pattern);
TreePatternParser parser =
new TreePatternParser(tokenizer, this, new TreePatternTreeAdaptor());
TreePattern tpattern = (TreePattern)parser.Pattern();
// don't allow invalid patterns
if (tpattern == null ||
tpattern.IsNil ||
tpattern.GetType() == typeof(WildcardTreePattern))
{
return;
}
IDictionary <string, object> labels = new Dictionary <string, object>(); // reused for each _parse
int rootTokenType = tpattern.Type;
Visit(t, rootTokenType, new VisitTreeWizardContextVisitor(this, visitor, labels, tpattern));
}
/** <summary>Return a List of subtrees matching pattern.</summary> */
public virtual IList Find(object t, string pattern)
{
IList subtrees = new List <object>();
// Create a TreePattern from the pattern
TreePatternLexer tokenizer = new TreePatternLexer(pattern);
TreePatternParser parser =
new TreePatternParser(tokenizer, this, new TreePatternTreeAdaptor());
TreePattern tpattern = (TreePattern)parser.Pattern();
// don't allow invalid patterns
if (tpattern == null ||
tpattern.IsNil ||
tpattern.GetType() == typeof(WildcardTreePattern))
{
return(null);
}
int rootTokenType = tpattern.Type;
Visit(t, rootTokenType, new FindTreeWizardContextVisitor(this, tpattern, subtrees));
return(subtrees);
}