Package org.oristool.lello.ast

Class Brackets

java.lang.Object
org.oristool.lello.ast.Expression
org.oristool.lello.ast.Brackets
public class Brackets extends Expression
Represents an expression enclosed in brackets. It does not have any particular behavior but it allows to determine how an expression was parenthesized before being parsed; also, it allows to add redundant parenthesis to an expression which is being formatted in order to enforce a certain evaluation order in a program which will take as input that formatted expression.

  • Constructor Details

    • Brackets

      public Brackets(Expression enclosed)
      Initializes a new expression in brackets.
      Parameters:
      enclosed - The enclosed expression.

    • Brackets

      public Brackets(List<Expression> expressions)
      Initializes a new vector, which is a list of expressions enclosed in brackets.
      Parameters:
      expressions - The enclosed expressions (vector components).

  • Method Details

    • getExpr

      public Expression getExpr()
      Retrieves the enclosed expression. If this object actually represents a vector an exception will be thrown.
      Returns:
      The enclosed expression.

    • getExpressions

      public List<Expression> getExpressions()
      Retrieves the enclosed expressions, which are the components of the vector. This method will never throw an exception, however it should be used only when this object is being considered with the semantics of a vector.
      Returns:
      The enclosed expressions (vector components).

    • eval

      public Value eval(Bindings bindings)
      Description copied from class: Expression
      Evaluates this expression using the specified variable bindings. Calling this method does not alter this expression.

      It is important to note that this method will not attempt any kind of simplification on the expression, which means that all the variables appearing in it must be either bound or correspond to Java static fields defined somewhere; if this is not the case an exception will be thrown.

      Specified by:
      eval in class Expression
      Parameters:
      bindings - Variable bindings.
      Returns:
      The value of the expression.

    • simplify

      public Expression simplify(Bindings bindings, SymbolicVisitor visitor)
      Description copied from class: Expression
      Tries to simplify this expression. Calling this method does not alter this expression.

      This method will not throw an exception if some variables appearing in the expression are not bound. However it may still be able to cancel a variable, if an appropriate rule is found.

      Specified by:
      simplify in class Expression
      Parameters:
      bindings - Variable bindings.
      visitor - The visitor implementing the simplification rules.
      Returns:
      A simplified expression if an appropriate rule was found, the same expression otherwise.

    • isZero

      public Truth isZero()
      Description copied from class: Expression
      Checks whether this expression is equal to 0 (with respect to the EPSILON tolerance).

      To decrease the probability that this method will return DONTKNOW, simplify or eval should be preventively called on this expression.

      Specified by:
      isZero in class Expression
      Returns:
      YES if this expression is equal to 0, NO if it is not, DONTKNOW if it is not known.

    • isOne

      public Truth isOne()
      Description copied from class: Expression
      Checks whether this expression is equal to 1 (with respect to the EPSILON tolerance).

      To decrease the probability that this method will return DONTKNOW, simplify or eval should be preventively called on this expression.

      Specified by:
      isOne in class Expression
      Returns:
      YES if this expression is equal to 1, NO if it is not, DONTKNOW if it is not known.

    • variables

      public Set<String> variables()
      Description copied from class: Expression
      Retrieves the names of all the variables appearing in this expression.
      Specified by:
      variables in class Expression
      Returns:
      set of variables

    • copy

      public Expression copy()
      Creates a copy of this object.
      Specified by:
      copy in class Expression
      Returns:
      a copy

    • format

      public String format(FormatVisitor visitor)
      Description copied from class: Expression
      Formats this expression.
      Overrides:
      format in class Expression
      Parameters:
      visitor - The visitor implementing the formatting rules.
      Returns:
      The formatted string.

    • toString

      public String toString()
      Overrides:
      toString in class Expression