CPExpression +expressionForConditional:trueExpression:falseExpression:

Conditional Expression : an expression using different expressions for
evaluation, depending of a predicate result.

Support for predicate parsing: ```TERNARY(predicate, trueExpression,
falseExpression)```

With init, equal, evaluation, parsing tests.

Foundation/CPPredicate/CPExpression.j

@@ -29,3 +29,4 @@
 @import "_CPSetExpression.j"
 @import "_CPSubqueryExpression.j"
 @import "_CPBlockExpression.j"
+@import "_CPConditionalExpression.j"

Foundation/CPPredicate/_CPConditionalExpression.j

@@ -0,0 +1,84 @@
+/*
+ * _CPConditionalExpression.j
+ *
+ * Created by cacaodev.
+ * Copyright 2015.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+@import "_CPPredicate.j"
+@import "_CPExpression.j"
+
+@implementation _CPConditionalExpression :  CPExpression
+{
+    CPPredicate   _predicate;
+    CPExpression  _trueExpression;
+    CPExpression  _falseExpression;
+}
+
+- (id)initWithPredicate:(CPPredicate)aPredicate trueExpression:(CPExpression)trueExpression falseExpression:(CPExpression)falseExpression
+{
+    self = [super initWithExpressionType:CPConditionalExpressionType];
+
+    if (self)
+    {
+        _predicate = aPredicate;
+        _trueExpression = trueExpression;
+        _falseExpression = falseExpression;
+    }
+
+    return self;
+}
+
+- (BOOL)isEqual:(id)object
+{
+    if (self === object)
+        return YES;
+
+    if (object === nil || object.isa !== self.isa || ![[object predicate] isEqual:_predicate] || ![[object trueExpression] isEqual:_trueExpression] || ![[object falseExpression] isEqual:_falseExpression])
+        return NO;
+
+    return YES;
+}
+
+- (CPPredicate)predicate
+{
+    return _predicate;
+}
+
+- (CPExpression)trueExpression
+{
+    return _trueExpression;
+}
+
+- (CPExpression)falseExpression
+{
+    return _falseExpression;
+}
+
+- (id)expressionValueWithObject:(id)object context:(CPDictionary)context
+{
+    var eval = [_predicate evaluateWithObject:object substitutionVariables:context];
+    var exp = eval ? _trueExpression : _falseExpression;
+
+    return [exp expressionValueWithObject:object context:context];
+}
+
+- (CPString)description
+{
+    return [CPString stringWithFormat:@"TERNARY(%@,%@,%@)", [_predicate predicateFormat], [_trueExpression description], [_falseExpression description]];
+}
+
+@end

Foundation/CPPredicate/_CPExpression.j

@@ -69,6 +69,10 @@ CPMinusSetExpressionType        = 9;
     An expression that returns the result of evaluating a block.
 */
 CPBlockExpressionType           = 10;
+/*!
+    An expression that returns an expression that depends on the evaluation of a predicate.
+*/
+CPConditionalExpressionType     = 11;
 
 /*!
     @ingroup foundation
@@ -284,6 +288,11 @@ A dictionary that the expression can use to store temporary state for one predic
     return [[_CPBlockExpression alloc] initWithBlock:aBlock arguments:args];
 }
 
++ (CPExpression)expressionForConditional:(CPPredicate)aPredicate trueExpression:(CPExpression)trueExpression falseExpression:(CPExpression)falseExpression
+{
+    return [[_CPConditionalExpression alloc] initWithPredicate:aPredicate trueExpression:trueExpression falseExpression:falseExpression];
+}
+
 // Getting Information About an Expression
 /*!
     Returns the expression type for the receiver.

Foundation/CPPredicate/_CPPredicate.j

@@ -751,11 +751,35 @@
         subpredicate = [self parsePredicate];
 
         if (![self scanString:@")" intoString:NULL])
-            CPRaiseParseError(self, @"expression");
+            CPRaiseParseError(self, @"predicate");
 
         return [[_CPSubqueryExpression alloc] initWithExpression:collection usingIteratorExpression:variableExpression predicate:subpredicate];
     }
 
+    if ([self scanString:@"TERNARY" intoString:NULL])
+    {
+        if (![self scanString:@"(" intoString:NULL])
+            CPRaiseParseError(self, @"expression");
+
+        var predicate,
+            trueExpression,
+            falseExpression;
+
+		predicate = [self parsePredicate];
+        if (![self scanString:@"," intoString:NULL])
+            CPRaiseParseError(self, @"predicate");
+
+        trueExpression = [self parseExpression];
+        if (![self scanString:@"," intoString:NULL])
+            CPRaiseParseError(self, @"expression");
+
+        falseExpression = [self parseExpression];
+        if (![self scanString:@")" intoString:NULL])
+            CPRaiseParseError(self, @"expression");
+
+        return [CPExpression expressionForConditional:predicate trueExpression:trueExpression falseExpression:falseExpression];
+    }
+
     if ([self scanString:@"FUNCTION" intoString:NULL])
     {
         if (![self scanString:@"(" intoString:NULL])

Tests/Foundation/CPPredicateTest.j

@@ -86,6 +86,10 @@
     } arguments:nil];
 
     [self assertNotNull:expression_block message:"Block Expression should not be nil"];
+
+    var expression_conditional = [CPExpression expressionForConditional:[CPPredicate predicateWithValue:YES] trueExpression:expression_minusset falseExpression:expression_block];
+
+    [self assertNotNull:expression_conditional message:"Conditional Expression should not be nil"];
 }
 
 - (void)testSetExpressionEvaluation
@@ -167,6 +171,14 @@
     [self assertTrue:([eval isEqual:"OBJA-B"]) message:"'" + [expression description]  + "' result is "+ eval + "but should be " + "OBJA-B"];
 }
 
+- (void)testConditionalExpressionEvaluation
+{
+    var expression = [CPExpression expressionForConditional:[CPPredicate predicateWithFormat:"SELF = $variable"] trueExpression:[CPExpression expressionForConstantValue:"TRUE_EXP"] falseExpression:[CPExpression expressionForConstantValue:"FALSE_EXP"]];
+
+    var eval = [expression expressionValueWithObject:"OBJ" context:@{"variable":"OBJ"}];
+    [self assertTrue:([eval isEqual:"TRUE_EXP"]) message:"'" + [expression description]  + "' result is "+ eval + "but should be " + "TRUE_EXP"];
+}
+
 - (void)testOptions
 {
     var pred = [[CPComparisonPredicate alloc] initWithLeftExpression:[CPExpression expressionForConstantValue:@"àa"] rightExpression:[CPExpression expressionForConstantValue:@"aà"] modifier:CPDirectPredicateModifier type:CPLikePredicateOperatorType options:3];
@@ -401,6 +413,9 @@
     predicate = [CPPredicate predicateWithFormat:@"a UNION {'b'} = {'a','b'}"];
     var left = [[predicate leftExpression] expressionValueWithObject:object context:nil];
     [self assertTrue:[left isEqualToSet:result] message:"Expression eval " + left + " should be " + result];
+
+    predicate = [CPPredicate predicateWithFormat:@"TERNARY(Record1.Children[SIZE] = 1, 'Single', Record1.Name) = 'John'"];
+    [self assertTrue:[predicate evaluateWithObject:dict] message:"Predicate " + predicate + " should evaluate to TRUE"];
 }
 
 - (void)testExpressionAndPredicateIsEqual
@@ -459,6 +474,10 @@
     pred1 = [CPPredicate predicateWithFormat:@"a = 'a' AND b = 'b'"];
     pred2 = [CPPredicate predicateWithFormat:@"a = 'a' AND b = 'b'"];
     [self assert:pred1 equals:pred2];
+
+    pred1 = [CPPredicate predicateWithFormat:@"TERNARY(Record1.Children[FIRST] BEGINSWITH Record1.Name, 'SAME', 'DIFFERENT') = 'DIFFERENT'"];
+    pred2 = [CPPredicate predicateWithFormat:@"TERNARY(Record1.Children[FIRST] BEGINSWITH Record1.Name, 'SAME', 'DIFFERENT') = 'DIFFERENT'"];
+    [self assert:pred1 equals:pred2];
 }
 
 - (void)testExpressionAndPredicateIsNotEqualToNil
@@ -510,6 +529,10 @@
 
     [self assert:pred1 notEqual:nil];
 
+    pred1 = [CPPredicate predicateWithFormat:@"TERNARY(Record1.Children[FIRST] BEGINSWITH Record1.Name, 'SAME', 'DIFFERENT') = 'DIFFERENT'"];
+
+    [self assert:pred1 notEqual:nil];
+
     pred1 = [CPPredicate predicateWithFormat:@"$x CONTAINS 'a'"];
 
     [self assert:pred1 notEqual:nil];