/** <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;
}
/** <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>
* 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;
}
