Example.swift

var leftExpressions = [
    NSExpression(forKeyPath: "pageTitle"),
    NSExpression(forKeyPath: "pageDescription"),
    NSExpression(forKeyPath: "content"),
    NSExpression(forKeyPath: "url")
]
var operatorTypes = [
    NSNumber(value: NSComparisonPredicate.Operator.equalTo.rawValue),
    NSNumber(value: NSComparisonPredicate.Operator.contains.rawValue),
    NSNumber(value: NSComparisonPredicate.Operator.beginsWith.rawValue),
    NSNumber(value: NSComparisonPredicate.Operator.endsWith.rawValue),
    NSNumber(value: NSComparisonPredicate.Operator.like.rawValue),
    NSNumber(value: NSComparisonPredicate.Operator.matches.rawValue),
    NSNumber(value: NSComparisonPredicate.Operator.notEqualTo.rawValue)
]
let someTemplate = NSPredicateEditorRowTemplate(leftExpressions: leftExpressions,
                                                rightExpressionAttributeType: NSAttributeType.stringAttributeType,
                                                modifier: NSComparisonPredicate.Modifier.direct,
                                                operators: operatorTypes,
                                                options: Int(NSComparisonPredicate.Options.caseInsensitive.rawValue))

predicateEditor.formattingStringsFilename = "PredicateStrings"
predicateEditor.rowTemplates = [someTemplate]

NSPredicateEditor+FooPredicate.h

//
//  NSPredicateEditor+FooPredicate.h
//  Elephant
//
//  Created by Tyler Hall on 1/25/20.
//  Copyright © 2020 Click On Tyler. All rights reserved.
//

#import <AppKit/AppKit.h>


#import <Cocoa/Cocoa.h>

NS_ASSUME_NONNULL_BEGIN

@interface NSPredicateEditor (FooPredicate)

- (void)exportStrings;

@end

NS_ASSUME_NONNULL_END

NSPredicateEditor+FooPredicate.m

//
//  NSPredicateEditor+FooPredicate.m
//  Elephant
//
//  Created by Tyler Hall on 1/25/20.
//  Copyright © 2020 Click On Tyler. All rights reserved.
//

#import "NSPredicateEditor+FooPredicate.h"

#import <AppKit/AppKit.h>


@implementation NSPredicateEditor (FooPredicate)

- (void)exportStrings
{
    NSData *data = [self performSelector:@selector(_generateFormattingDictionaryStringsFile)];
    NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF16StringEncoding];
    NSLog(@"%@", str);
}

@end

PredicateStrings.strings

/* 
  Predicates.strings
  Elephant

  Created by Tyler Hall on 1/25/20.
  Copyright © 2020 Click On Tyler. All rights reserved.
*/

"%[Any]@ of the following are true" = "%1$[Any]@ of the following are true";
"%[None]@ of the following are true" = "%1$[None]@ of the following are true";

"%[pageTitle]@ %[is]@ %@" = "%1$[Title]@ %2$[is]@ %3$@";
"%[pageTitle]@ %[contains]@ %@" = "%1$[Title]@ %2$[contains]@ %3$@";
"%[pageTitle]@ %[begins with]@ %@" = "%1$[Title]@ %2$[begins with]@ %3$@";
"%[pageTitle]@ %[ends with]@ %@" = "%1$[Title]@ %2$[ends with]@ %3$@";
"%[pageTitle]@ %[is like]@ %@" = "%1$[Title]@ %2$[is like]@ %3$@";
"%[pageTitle]@ %[matches]@ %@" = "%1$[Title]@ %2$[matches]@ %3$@";
"%[pageTitle]@ %[is not]@ %@" = "%1$[Title]@ %2$[is not]@ %3$@";

"%[pageDescription]@ %[is]@ %@" = "%1$[Meta Description]@ %2$[is]@ %3$@";
"%[pageDescription]@ %[contains]@ %@" = "%1$[Meta Description]@ %2$[contains]@ %3$@";
"%[pageDescription]@ %[begins with]@ %@" = "%1$[Meta Description]@ %2$[begins with]@ %3$@";
"%[pageDescription]@ %[ends with]@ %@" = "%1$[Meta Description]@ %2$[ends with]@ %3$@";
"%[pageDescription]@ %[is like]@ %@" = "%1$[Meta Description]@ %2$[is like]@ %3$@";
"%[pageDescription]@ %[matches]@ %@" = "%1$[Meta Description]@ %2$[matches]@ %3$@";
"%[pageDescription]@ %[is not]@ %@" = "%1$[Meta Description]@ %2$[is not]@ %3$@";

"%[content]@ %[is]@ %@" = "%1$[Web Page Contents]@ %2$[is]@ %3$@";
"%[content]@ %[contains]@ %@" = "%1$[Web Page Contents]@ %2$[contains]@ %3$@";
"%[content]@ %[begins with]@ %@" = "%1$[Web Page Contents]@ %2$[begins with]@ %3$@";
"%[content]@ %[ends with]@ %@" = "%1$[Web Page Contents]@ %2$[ends with]@ %3$@";
"%[content]@ %[is like]@ %@" = "%1$[Web Page Contents]@ %2$[is like]@ %3$@";
"%[content]@ %[matches]@ %@" = "%1$[Web Page Contents]@ %2$[matches]@ %3$@";
"%[content]@ %[is not]@ %@" = "%1$[Web Page Contents]@ %2$[is not]@ %3$@";

"%[url]@ %[is]@ %@" = "%1$[URL]@ %2$[is]@ %3$@";
"%[url]@ %[contains]@ %@" = "%1$[URL]@ %2$[contains]@ %3$@";
"%[url]@ %[begins with]@ %@" = "%1$[URL]@ %2$[begins with]@ %3$@";
"%[url]@ %[ends with]@ %@" = "%1$[URL]@ %2$[ends with]@ %3$@";
"%[url]@ %[is like]@ %@" = "%1$[URL]@ %2$[is like]@ %3$@";
"%[url]@ %[matches]@ %@" = "%1$[URL]@ %2$[matches]@ %3$@";
"%[url]@ %[is not]@ %@" = "%1$[URL]@ %2$[is not]@ %3$@";