wordfrequencies.m

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
	@autoreleasepool {
		NSCountedSet *set = [NSCountedSet set];
		NSError *error;
		NSString *corpus = [NSString stringWithContentsOfFile:@"some-file.txt" encoding:NSUTF8StringEncoding error:&error];
		[corpus enumerateSubstringsInRange:NSMakeRange(0, [corpus length]) options:NSStringEnumerationByWords usingBlock:^(NSString *word, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
			[set addObject:word];
		}];
		
		NSSortDescriptor *countDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"self" ascending:NO comparator:^NSComparisonResult(id obj1, id obj2) {
			if ([set countForObject:obj1] < [set countForObject:obj2]) {
				return NSOrderedAscending;
			}
			if ([set countForObject:obj1] == [set countForObject:obj2]) {
				return NSOrderedSame;
			}
			return NSOrderedDescending;
		}];
		
		NSArray *sorted = [set sortedArrayUsingDescriptors:@[countDescriptor]];
		
		for (NSString *word in sorted) {
			NSLog(@"%lu - %@", [set countForObject:word], word);
		}
	}
	return 0;
}