Haskell Cookbook

Source formatting

You must have also noticed how the Haskell source code is formatted. The blocks are indented by white spaces. There is no hard and fast rule for indenting; however, it must be noted that there has to be a significant white space indent for a source code block, such as the let clause or the where clause. A simple guideline is that any block should be indented in such a way that it is left aligned and increases the readability of the code. A good Haskell source is easy to read.