[skimpycompiler]

Types + pattern matching -- best combination for working with trees.

I'm not sure if there's a library in F# similar to HXT, but in Haskell, working with large xml structures is a breeze.

[davexunit]

I use a pattern matcher that can match against types in Scheme, a language without static typing. Static types are just not the crucial feature that some people make them out to be. I believe this criticism of Pascal and C from SICP applies to other languages with static types (sans the pointer stuff):

    Pascal and C admit structures whose elements are structures. However,
    this requires that the programmer manipulate pointers explicitly, and
    adhere to the restriction that each field of a structure can contain
    only elements of a prespecified form. Unlike Lisp with its pairs,
    these languages have no built-in general-purpose glue that makes it
    easy to manipulate compound data in a uniform way.

With static typing, it's also difficult to write procedures that operate on arguments of which the type is none of the procedure's business.

https://sarabander.github.io/sicp/html/2_002e2.xhtml#FOOT73

[skimpycompiler]

Well, I was definitely not mentioning Pascal and C. Haskell's type system is much easier to work with.

The thing is that any operation you are using on those arguments (of which the type is none of the procedure's business) can be described by an interface which the argument implements.

You're much safer knowing in compile time that the operations you'll use will be valid, instead of hoping something doesn't crash in runtime.

[jbeja]

There is also zippers