Deprecating +sharedMathEvaluator.

The name is wrong.  +shared* implies a singleton, which this is not.  The proper name is +defaultMathEvaluator (like +[NSFileManager defaultManager])

Command line demo/main.m

@@ -21,7 +21,7 @@
 
 void listFunctions() {
 	printf("\nFunctions available:\n");
-	NSArray * functions = [[DDMathEvaluator sharedMathEvaluator] registeredFunctions];
+	NSArray * functions = [[DDMathEvaluator defaultMathEvaluator] registeredFunctions];
 	for (NSString * function in functions) {
 		printf("\t%s()\n", [function UTF8String]);
 	}

DDMathParser/DDExpression.m

@@ -48,7 +48,7 @@ - (NSNumber *)evaluateWithSubstitutions:(NSDictionary *)substitutions evaluator:
 }
 - (DDExpression *)simplifiedExpression {
 	NSError *error = nil;
-	DDExpression *simplified = [self simplifiedExpressionWithEvaluator:[DDMathEvaluator sharedMathEvaluator] error:&error];
+	DDExpression *simplified = [self simplifiedExpressionWithEvaluator:[DDMathEvaluator defaultMathEvaluator] error:&error];
 	if (error != nil) {
 		NSLog(@"error: %@", error);
 		return nil;

DDMathParser/DDMathEvaluator.h

@@ -24,7 +24,8 @@ typedef NSNumber* (^DDVariableResolver)(NSString *);
 @property (nonatomic, copy) DDFunctionResolver functionResolver;
 @property (nonatomic, copy) DDVariableResolver variableResolver;
 
-+ (id)sharedMathEvaluator;
++ (id)sharedMathEvaluator __attribute__((deprecated("Use +defaultMathEvaluator instead")));
++ (instancetype)defaultMathEvaluator;
 
 - (BOOL)registerFunction:(DDMathFunction)function forName:(NSString *)functionName;
 - (void)unregisterFunctionWithName:(NSString *)functionName;

DDMathParser/DDMathEvaluator.m

@@ -23,14 +23,18 @@ @implementation DDMathEvaluator {
     _DDFunctionEvaluator *_functionEvaluator;
 }
 
-static DDMathEvaluator * _sharedEvaluator = nil;
 
 + (id)sharedMathEvaluator {
+    return [self defaultMathEvaluator];
+}
+
++ (instancetype)defaultMathEvaluator {
+    static DDMathEvaluator * _defaultEvaluator = nil;
     static dispatch_once_t onceToken;
     dispatch_once(&onceToken, ^{
-		_sharedEvaluator = [[DDMathEvaluator alloc] init];
+		_defaultEvaluator = [[DDMathEvaluator alloc] init];
     });
-	return _sharedEvaluator;
+	return _defaultEvaluator;
 }
 
 - (id)init {
@@ -49,12 +53,6 @@ - (id)init {
 	return self;
 }
 
-- (void)dealloc {
-	if (self == _sharedEvaluator) {
-		_sharedEvaluator = nil;
-	}
-}
-
 #pragma mark - Properties
 
 - (void)setUsesHighPrecisionEvaluation:(BOOL)usesHighPrecisionEvaluation {

DDMathParser/NSString+DDMathParsing.m

@@ -27,7 +27,7 @@ - (NSNumber *)numberByEvaluatingStringWithSubstitutions:(NSDictionary *)substitu
 
 - (NSNumber *)numberByEvaluatingStringWithSubstitutions:(NSDictionary *)substitutions error:(NSError **)error {
 	DDExpression * e = [DDExpression expressionFromString:self error:error];
-    return [[DDMathEvaluator sharedMathEvaluator] evaluateExpression:e withSubstitutions:substitutions error:error];
+    return [[DDMathEvaluator defaultMathEvaluator] evaluateExpression:e withSubstitutions:substitutions error:error];
 }
 
 @end

DDMathParser/_DDFunctionExpression.m

@@ -74,7 +74,7 @@ - (DDExpression *)simplifiedExpressionWithEvaluator:(DDMathEvaluator *)evaluator
 	}
 
 	if (canSimplify) {
-		if (evaluator == nil) { evaluator = [DDMathEvaluator sharedMathEvaluator]; }
+		if (evaluator == nil) { evaluator = [DDMathEvaluator defaultMathEvaluator]; }
 
         id result = [evaluator evaluateExpression:self withSubstitutions:nil error:error];