Package org.codehaus.groovy.syntax

Class Reduction

java.lang.Object
org.codehaus.groovy.syntax.CSTNode
org.codehaus.groovy.syntax.Reduction
public class Reduction extends CSTNode
A syntax reduction produced by the Parser during syntactic analysis. Represents a node in the concrete syntax tree (CST) that contains a root Token and zero or more child CSTNode elements.
See Also:

  • Field Details

    • EMPTY

      public static final Reduction EMPTY
      Singleton empty reduction (read-only).

  • Constructor Details

    • Reduction

      public Reduction(Token root)
      Constructs a Reduction with the specified root token.
      Parameters:
      root - the root Token of this reduction

  • Method Details

    • newContainer

      public static Reduction newContainer()
      Creates a new Reduction with Token.NULL as its root. Useful for creating container nodes with no specific type.
      Returns:
      a new Reduction with a null root token

    • isEmpty

      public boolean isEmpty()
      Returns true if this reduction is completely empty (no elements, not even a root).
      Overrides:
      isEmpty in class CSTNode
      Returns:
      true if empty

    • size

      public int size()
      Returns the number of elements in this reduction (including the root token).
      Specified by:
      size in class CSTNode
      Returns:
      the number of elements

    • get

      public CSTNode get(int index)
      Returns the element at the specified index, or null if the index is out of bounds.
      Specified by:
      get in class CSTNode
      Parameters:
      index - the element index (0 for root)
      Returns:
      the element at the index, or null if not found

    • getRoot

      public Token getRoot()
      Returns the root token of this reduction. The root is always at index 0 and indicates the syntactic type.
      Specified by:
      getRoot in class CSTNode
      Returns:
      the root token, or null if this reduction is empty

    • markAsExpression

      public void markAsExpression()
      Marks this reduction as a complete expression. This flag is used by the parser to distinguish complete expressions from partial constructs.
      Overrides:
      markAsExpression in class CSTNode

    • isAnExpression

      public boolean isAnExpression()
      Returns true if this node represents a complete expression. A reduction is considered an expression if it has the Types.COMPLEX_EXPRESSION meaning or has been explicitly marked as an expression.
      Overrides:
      isAnExpression in class CSTNode
      Returns:
      true if this is an expression

    • add

      public CSTNode add(CSTNode element)
      Adds an element to the end of this reduction.
      Overrides:
      add in class CSTNode
      Parameters:
      element - the element to add
      Returns:
      the added element

    • set

      public CSTNode set(int index, CSTNode element)
      Sets the element at the specified index. If the index is beyond the current size, intermediate positions are filled with null. The root element (index 0) must be a Token.
      Overrides:
      set in class CSTNode
      Parameters:
      index - the element index
      element - the element to set
      Returns:
      the set element
      Throws:
      GroovyBugError - if trying to set a non-Token as root, or if operating on EMPTY

    • remove

      public CSTNode remove(int index)
      Removes the element at the specified index. Cannot remove the root element (index 0).
      Parameters:
      index - the element index (must be > 0)
      Returns:
      the removed element
      Throws:
      GroovyBugError - if trying to remove the root element

    • asReduction

      public Reduction asReduction()
      Creates a Reduction from this node. Returns self if the node is already a Reduction.
      Specified by:
      asReduction in class CSTNode
      Returns:
      this node as a Reduction