A very simple template engine for iOS

NSString+template.c

#import "NSString+template.h"

@implementation NSString (template)

+(NSString*)stringWithTemplate:(NSString*)template 
                       fromMap:(NSDictionary*)map
{
    NSString* retStr = nil;    
    NSMutableString* buffer = [NSMutableString new];    
    NSScanner* scanner = [[NSScanner alloc] initWithString:template];    
    NSString* tempString = nil;
    
    while([scanner scanUpToString:@"$[" intoString:&tempString])
    {
        NSString* key = nil;
        NSString* value = nil;
        
        [buffer appendString:tempString];
        if([scanner isAtEnd])
        {
            break;
        }
        
        [scanner scanString:@"$[" intoString:nil];
        [scanner scanUpToString:@"]" intoString:&key];
        [scanner scanString:@"]" intoString:nil];
        
        if(key)
        {
            value = [map objectForKey:key];
        }
        
        if(value)
        {
            [buffer appendString:value];
        }
        else
        {
            [buffer appendFormat:@"$[%@]", key];
        }   
    }
    
    retStr = [NSString stringWithString:buffer];
    [buffer release];
    [scanner release];
    
    return retStr;    
}

@end

NSString+template.h

#import <Foundation/Foundation.h>

@interface NSString (template)

+(NSString*)stringWithTemplate:(NSString*)template 
                       fromMap:(NSDictionary*)map;
                

@end

Sample.c

- (void)test
{
    NSString* testTemplate = @"Hello $[name], welcome to $[city].";
    
    NSString* testString = 
        [NSString stringWithTemplate:testTemplate 
                             fromMap:[NSDictionary dictionaryWithObjectsAndKeys:
                                      @"Popcorny", @"name"
                                      @"Taipei", @"city",
                                      nil]];
    NSLog(@"%@", testString);    
}