Class TaskJuggler::LogicalOperation
In: lib/taskjuggler/LogicalOperation.rb
Parent: Object

A LogicalOperation is the basic building block for a LogicalExpression. A logical operation has one or two operands and an operator. The operands can be LogicalOperation objects, fixed values or references to project data. The LogicalOperation can be evaluated in a certain context. This contexts determines the actual values of the project data references. The evaluation is done by calling LogicalOperation#eval. The result must be of a type that responds to all the operators that are used in the eval method.

Methods

eval   new   to_s  

Attributes

operand1  [R] 
operand2  [RW] 
operator  [RW] 

Public Class methods

new(opnd1, operator = nil, opnd2 = nil)

Create a new LogicalOperation object. _opnd1_ is the mandatory operand. The @operand2 and the @operator can be set later.

[Source]

# File lib/taskjuggler/LogicalOperation.rb, line 35
    def initialize(opnd1, operator = nil, opnd2 = nil)
      @operand1 = opnd1
      @operand2 = opnd2
      @operator = operator
    end

Public Instance methods

eval(expr)

Evaluate the expression in a given context represented by expr of type LogicalExpression. The result must be of a type that responds to all the operators of this function.

[Source]

# File lib/taskjuggler/LogicalOperation.rb, line 44
    def eval(expr)
      case @operator
      when nil
        if @operand1.respond_to?(:eval)
          # An operand can be a fixed value or another term. This could be a
          # LogicalOperation, LogicalFunction or anything else that provides
          # an appropriate eval() method.
          return @operand1.eval(expr)
        else
          return @operand1
        end
      when '~'
        return !coerceBoolean(@operand1.eval(expr), expr)
      when '>', '>=', '=', '<', '<=', '!='
        # Evaluate the operation for all 2 operand operations that can be
        # either interpreted as date, numbers or Strings.
        opnd1 = @operand1.eval(expr)
        opnd2 = @operand2.eval(expr)
        if opnd1.is_a?(TjTime)
          res= evalBinaryOperation(opnd1, operator, opnd2) do |o|
            coerceTime(o, expr)
          end
          return res
        elsif opnd1.is_a?(Fixnum) || opnd1.is_a?(Float) || opnd1.is_a?(Bignum)
          return evalBinaryOperation(opnd1, operator, opnd2) do |o|
            coerceNumber(o, expr)
          end
        elsif opnd1.is_a?(RichTextIntermediate)
          return evalBinaryOperation(opnd1.to_s, operator, opnd2) do |o|
            coerceString(o, expr)
          end
        elsif opnd1.is_a?(String)
          return evalBinaryOperation(opnd1, operator, opnd2) do |o|
            coerceString(o, expr)
          end
        else
          expr.error("First operand of a binary operation must be a date, " +
                     "a number or a string: #{opnd1.class}")
        end
      when '&'
        return coerceBoolean(@operand1.eval(expr), expr) &&
               coerceBoolean(@operand2.eval(expr), expr)
      when '|'
        return coerceBoolean(@operand1.eval(expr), expr) ||
               coerceBoolean(@operand2.eval(expr), expr)
      else
        expr.error("Unknown operator #{@operator} in logical expression")
      end
    end
to_s(query)

Convert the operation into a textual representation.

[Source]

# File lib/taskjuggler/LogicalOperation.rb, line 95
    def to_s(query)
      if @operator.nil?
        operand_to_s(@operand1, query)
      elsif @operand2.nil?
        @operator + operand_to_s(@operand1, query)
      else
        "(#{operand_to_s(@operand1, query)} #{@operator} " +
        "#{operand_to_s(@operand2, query)})"
      end
    end

[Validate]