Developing Web Applications with Haskell and Yesod

Errata for Developing Web Applications with Haskell and Yesod

Submit your own errata for this product.


The errata list is a list of errors and their corrections that were found after the product was released.

The following errata were submitted by our customers and have not yet been approved or disproved by the author or editor. They solely represent the opinion of the customer.


Color Key: Serious Technical Mistake Minor Technical Mistake Language or formatting error Typo Question Note Update



Version Location Description Submitted By Date Submitted
PDF Page 5
2nd pagagraph

There is an unintended greater-than sign in front of "various APIs".

Ruben Verborgh  May 04, 2012 
Printed Page 5
2nd paragraph

On page 5, 2nd paragraph there is a typo, it is: there is a greater than sign [>] before the word various...see following: "...throughout the >various APIs."

patrick lynch  Mar 12, 2013 
Printed Page 15
3rd paragraph

I downloaded the source code and did the following: 1. download was done on a Mac. 2. I saved the file to helloWorld.hs 3. I went to my terminal screen and executed: runhaskell helloworld.hs 4. on the terminal the following appeared: hell yeah 5. so far, so good 6. I went to my browser and entered the url: http://localhost:3000 7. I was expecting to see the following on my browser: <!DOCTYPE html> <html><head><title></head><body>hell yeah</body></html> 8. Unfortunately, I get the following message: "Safari can't connect to Server Safari can't open page "http://localhost:3000" because Safari can't connect to server "localhost" I've also noted that there seems to be no activity on this book. Am I making a mistake by trying to use it?

Note from the Author or Editor:
This is probably better discussed on the mailing list or an issue tracker than book errata. One possibility is that there's a hostname binding issue at play; try connecting to http://127.0.0.1:3000 instead. Did "hell yeah" literally appear on the terminal? If so, where did that come from? I'm not sure where you're looking for activity around the book, but most discussions happen on the Yesod mailing list: http://groups.google.com/group/yesodweb

patrick lynch  Feb 24, 2014 
Printed Page 15
3rd paragraph

I can't get the helloworld.hs program to work on the browser. Please see my previously entered errata for procedure used. I used the url http://127.0.0.1:3000 but it gives the same error on the browser. Note: the "hell yes" is displayed on the terminal. I've gone to the Haskell user group and the Yesod group for advise. Good day. Ps Note: this program was downloaded and is slightly different than the one in the book - curioser and curioser.

Note from the Author or Editor:
Like was requested on the mailing list, I think I'll need to see the code you're running, because I certainly didn't write "hell yes" in the book.

patrick lynch  Feb 25, 2014 
PDF Page 53
Code block at the top of the page, lines 11 and 13 from the top

In the GetRootR function, the "<p" are not complete. They need ">" to be correct, the function should read as such: getRootR = defaultLayout [whamlet| <p> <a href=@{RootR}>RootR <p> <a href=@{FooR}>FooR |]

Brye Verdier  Aug 19, 2012 
PDF, ePub Page 71
line 4

The example of using forms in Yesod (under Synopsis) contains code that does not compile. The definition of function getRootR in the pdf and ebook versions differ from that on the author's website. This line: ((_,widget), enctype) <- generateFormPost personForm should apparently be (as in the website version): (widget, enctype) <- generateFormPost personForm

Anonymous  Oct 10, 2012