lib6005.parser

Interface ParseTree<NT extends Enum<NT>>

Type Parameters:

NT - is an Enum type with one value for every nonterminal in the grammar. See Parser for more information.

public interface ParseTree<NT extends Enum<NT>>

Represents an immutable parse tree. Each node represents the application of a production rule from the grammar, "name ::= expr". The node's name() is the nonterminal on the left side of the production rule, and the node's children() are the production rules that were matched for each nonterminal used in the righthand side (expr). A node also has text() representing the entire substring matched by this node's subtree.

If the grammar used @skip to skip over some nonterminals automatically, then the skipped subtrees do not appear among this node's children(), but can be found by using allChildren() or childrenByName().

Author:

6.005/6.031 course staff

Method Summary

Modifier and Type	Method and Description
List<ParseTree<NT>>	allChildren() Get all of this node's children, including @skip rules.
List<ParseTree<NT>>	children() Get this node's children.
List<ParseTree<NT>>	childrenByName(NT name) Get the children that correspond to a particular production rule
boolean	isSkipped() Test if this node is in a subtree that was @skipped.
NT	name() Get this node's name.
String	text() Get this subtree's text.

Method Detail

name

NT name()

Get this node's name.

Returns:

the nonterminal corresponding to this node in the parse tree.

children

List<ParseTree<NT>> children()

Get this node's children.

Returns:

the children of this node, in order, excluding @skipped subtrees

text

String text()

Get this subtree's text.

Returns:

the substring of the original string that this subtree matched

childrenByName

List<ParseTree<NT>> childrenByName(NT name)

Get the children that correspond to a particular production rule

Parameters:

name - Name of the nonterminal corresponding to the desired production rule.

Returns:

children that represent matches of name's production rule.

allChildren

List<ParseTree<NT>> allChildren()

Get all of this node's children, including @skip rules.

Returns:

all the children of this node, in order, including @skipped subtrees

isSkipped

boolean isSkipped()

Test if this node is in a subtree that was @skipped.

Returns:

true iff this node is part of a subtree that was automatically skipped over by a @skip rule.