Let's take a concrete example: Say you have a programming language L that has a parser that is implemented in lang. A, and an interpreter implemented in lang. B

Let's take a concrete example: Say you have a programming language L that has a parser that is implemented in lang. A, and an interpreter implemented in lang. B. Now if you want the interpreter (in B) to interpret the program, you need some structured data to come from the parser (in A). Abstract syntax trees (ASTs) are the usual conceptual tool for this. Now assume that the parser outputs an AST that is described by something, like for example an algebraic data type (ADT). Assume that the structure of the ADT conforms to some type protocol. Now the interpreter can implement the ADT in its language (B) and thereby take the ADT directly as input. Now you can use a "typed pipeline" to easily combine these two programs: > parser directory/file.lang | interpreter Does this make sense? Would it have some utility?