What is the simplest implementation of Markdown for a Cocoa application?

Question

I\'m writing a Cocoa application in Objective-C, and I would like to be able to incorporate Markdown. The user will enter text in Markdown syntax, click an \"export\" button

Answer 1

I found problems with processing large amounts of markdown with these C-based libraries.

There's a very simple Obj-C library that worked for me here:

https://github.com/mdiep/MMMarkdown

---

Steps to use MMMarkdown:

1. Build the OS X or iOS target

2. Copy include/MMMarkdown.h and either lib/libMMMarkdown-Mac.a or lib/libMMMarkdown-iOS.a into your project

3. Then the code is:

#import "MMMarkdown.h"

NSError  *error;
NSString *markdown   = @"# Example\nWhat a library!";
NSString *htmlString = [MMMarkdown HTMLStringWithMarkdown:markdown error:&error];
// Returns @"<h1>Example</h1>\n<p>What a library!</p>"

Answer 2

1. Oliver Letterer's GHMarkdownParser translate markdown to HTML.
2. Phil Toland's QLMarkdown QuickLook generator for markdown files.

Answer 3

I've used peg-markdown, it's much faster than the original perl and can handle a few syntax extensions if you enable them.

Answer 4

I had a look at the various options, and in the end found libsoldout, a very small C implementation that's quite easy to integrate. You just need to include array.[ch], buffer.[ch], markdown.[ch], and renderers.[ch] in your Xcode project, then you can convert an NSString from markdown to HTML like so:

NSString *rawMarkdown;
const char * prose = [rawMarkdown UTF8String];  
struct buf *ib, *ob;       

int length = rawMarkdown.length + 1;

ib = bufnew(length);
bufgrow(ib, length);
memcpy(ib->data, prose, length);
ib->size = length;

ob = bufnew(64);
markdown(ob, ib, &mkd_xhtml);

NSString *shinyNewHTML = [NSString stringWithUTF8String: ob->data];
NSLog(@"%@", shinyNewHTML);

bufrelease(ib);
bufrelease(ob);

Answer 5

You may want to check out the open-source app Macdown which I wrote (or alternatively rentzsch's Markdownlive), which incorporate this functionality as the sole purpose of the two apps.

Answer 6

I just used the Sundown implementation which includes SmartyPants support, in an iPad app with great success. Took about 15 minutes to build a test app.

Assume you have a UITextView *textView (which you setDelegate:self) and also a UIWebView *webView in which to display the results:

- (void) textViewDidEndEditing:(UITextView *)textView
{
    NSString *rawMarkdown = [textView text];
    const char * prose = [rawMarkdown UTF8String];  
    struct buf *ib, *ob;       

    int length = [rawMarkdown lengthOfBytesUsingEncoding:NSUTF8StringEncoding] + 1;

    ib = bufnew(length);
    bufgrow(ib, length);
    memcpy(ib->data, prose, length);
    ib->size = length;

    ob = bufnew(64);

    struct sd_callbacks callbacks;
    struct html_renderopt options;
    struct sd_markdown *markdown;


    sdhtml_renderer(&callbacks, &options, 0);
    markdown = sd_markdown_new(0, 16, &callbacks, &options);

    sd_markdown_render(ob, ib->data, ib->size, markdown);
    sd_markdown_free(markdown);


    NSString *shinyNewHTML = [NSString stringWithUTF8String: ob->data];
    [webView loadHTMLString:shinyNewHTML baseURL:[[NSURL alloc] initWithString:@""]];

    bufrelease(ib);
    bufrelease(ob);
}