TaskJuggler::LogicalOperation

    # File lib/LogicalOperation.rb, line 33
33:     def initialize(opnd1, operator = nil, opnd2 = nil)
34:       @operand1 = opnd1
35:       @operand2 = opnd2
36:       @operator = operator
37:     end

    # File lib/LogicalOperation.rb, line 42
42:     def eval(expr)
43:       case @operator
44:       when nil
45:         if @operand1.respond_to?(:eval)
46:           # An operand can be a fixed value or another term. This could be a
47:           # LogicalOperation, LogicalFunction or anything else that provides
48:           # an appropriate eval() method.
49:           return @operand1.eval(expr)
50:         else
51:           return @operand1
52:         end
53:       when '~'
54:         return !coerceBoolean(@operand1.eval(expr), expr)
55:       when '>', '>=', '=', '<', '<=', '!='
56:         # Evaluate the operation for all 2 operand operations that can be
57:         # either interpreted as date, numbers or Strings.
58:         opnd1 = @operand1.eval(expr)
59:         opnd2 = @operand2.eval(expr)
60:         if opnd1.is_a?(TjTime)
61:           res= evalBinaryOperation(opnd1, operator, opnd2) do |o|
62:             coerceTime(o, expr)
63:           end
64:           return res
65:         elsif opnd1.is_a?(Fixnum) || opnd1.is_a?(Float) || opnd1.is_a?(Bignum)
66:           return evalBinaryOperation(opnd1, operator, opnd2) do |o|
67:             coerceNumber(o, expr)
68:           end
69:         elsif opnd1.is_a?(RichTextIntermediate)
70:           return evalBinaryOperation(opnd1.to_s, operator, opnd2) do |o|
71:             coerceString(o, expr)
72:           end
73:         elsif opnd1.is_a?(String)
74:           return evalBinaryOperation(opnd1, operator, opnd2) do |o|
75:             coerceString(o, expr)
76:           end
77:         else
78:           expr.error("First operand of a binary operation must be a date, " +
79:                      "a number or a string: #{opnd1.class}")
80:         end
81:       when '&'
82:         return coerceBoolean(@operand1.eval(expr), expr) &&
83:                coerceBoolean(@operand2.eval(expr), expr)
84:       when '|'
85:         return coerceBoolean(@operand1.eval(expr), expr) ||
86:                coerceBoolean(@operand2.eval(expr), expr)
87:       else
88:         expr.error("Unknown operator #{@operator} in logical expression")
89:       end
90:     end

     # File lib/LogicalOperation.rb, line 93
 93:     def to_s(query)
 94:       if @operator.nil?
 95:         operand_to_s(@operand1, query)
 96:       elsif @operand2.nil?
 97:         @operator + operand_to_s(@operand1, query)
 98:       else
 99:         "(#{operand_to_s(@operand1, query)} #{@operator} " +
100:         "#{operand_to_s(@operand2, query)})"
101:       end
102:     end

     # File lib/LogicalOperation.rb, line 140
140:     def coerceBoolean(val, expr)
141:       # First the obvious ones.
142:       return val if val.class == TrueClass || val.class == FalseClass
143:       # An empty String means false, else true.
144:       return !val.empty? if val.is_a?(String)
145:       # In TJP logic 'non 0' means false.
146:       return val != 0 if val.is_a?(Fixnum) || val.is_a?(Bignum)
147: 
148:       expr.error("Operand #{val} can't be evaluated to true or false.")
149:     end

     # File lib/LogicalOperation.rb, line 152
152:     def coerceNumber(val, expr)
153:       unless val.is_a?(Fixnum) || val.is_a?(Float) || val.is_a?(Bignum)
154:         expr.error("Operand #{val} of type #{val.class} must be a number.")
155:       end
156:       val
157:     end

     # File lib/LogicalOperation.rb, line 160
160:     def coerceString(val, expr)
161:       unless val.respond_to?('to_s')
162:         expr.error("Operand #{val} of type #{val.class} can't be converted " +
163:                    "into a string")
164:       end
165:       val
166:     end

     # File lib/LogicalOperation.rb, line 169
169:     def coerceTime(val, expr)
170:       unless val.is_a?(TjTime)
171:         expr.error("Operand #{val} of type #{val.class} can't be converted " +
172:                    "into a date")
173:       end
174:       val
175:     end

     # File lib/LogicalOperation.rb, line 120
120:     def evalBinaryOperation(opnd1, operator, opnd2)
121:       case operator
122:       when '>'
123:         return yield(opnd1) > yield(opnd2)
124:       when '>='
125:         return yield(opnd1) >= yield(opnd2)
126:       when '='
127:         return yield(opnd1) == yield(opnd2)
128:       when '<'
129:         return yield(opnd1) < yield(opnd2)
130:       when '<='
131:         return yield(opnd1) <= yield(opnd2)
132:       when '!='
133:         return yield(opnd1) != yield(opnd2)
134:       else
135:         raise "Operator error"
136:       end
137:     end

     # File lib/LogicalOperation.rb, line 106
106:     def operand_to_s(operand, query)
107:       if operand.is_a?(LogicalOperation)
108:         operand.to_s(query)
109:       elsif operand.is_a?(String)
110:         "'#{operand}'"
111:       else
112:         operand.to_s
113:       end
114:     end