[mballantyne]

I suggest "Programming Languages: Application and Interpretation", available free here: http://cs.brown.edu/courses/cs173/2012/book/ It's an undergraduate-level programming languages class textbook.

Other books burn a lot of time on things like lexing and parsing; this one does not. In the lisp tradition, it assumes s-expressions and gets to the juicy bits of programming language semantics immediately: lexical scope, first class functions, objects, etc.

[bendmorris]

Second this. I'm writing a compiler now (https://github.com/kitlang/kit) and this book has been invaluable.

A few other tips:

* Use a parser generator. Parsing is more or less a solved problem; get it out of the way as fast as possible.

* Writing a language that compiles to another language is very helpful as you can often borrow the underlying language's implementation of a feature. Doubly helpful if you can leverage the underlying language's libraries for things like syscalls.

* Make a todo list (I like Trello for this) full of self-contained tasks. Pick one at a time, think through how you would implement that feature, and go to work. Compilers look like a lot of work in the beginning, but if you take one step at a time, one day you'll look back and have accomplished more than you realize. The list can also be helpful to avoid scope creep; add any new ideas to your backlog and deal with them later.

* Write unit tests, as you'll very likely want to refactor something down the line. Once your compiler becomes complex enough, add functional tests that verify entire programs can compile and run and produce the expected output.