lia

Rust macros are extremely impressive. This reminds me of Will Crichton's Lia library[0], which embeds a convenient matrix manipulation domain specific language inside of Rust. This seems like a very promising direction for fusing the low-level performance of Rust with the high-level readability and usability of a managed language. Exciting times. [0]:https://github.com/willcrichton/lia

This article shows a lot of the silliness in both a) writing compilers in C++ and b) re-creating well-worn compilers tools like parsers from scratch. 1. Their definition of values in the language (unfortunately called "Variables") is a product (class) over all possible types: class Variable { ... double numValue; string strValue; vector<Variable> tuple; string action; string varname; Constants::Type type; }; This means each value at runtime has a large memory footprint, as each instance of a value contains slots for all possible types even though only one will ever be filled. Sum types solve this problem. 2. The author intermixes parsing and code generation. This makes it difficult to implement any kind of optimizations, even for an interpreter. For example, in order to do function inlining in the author's

Counterpoint: I'm writing a language to do just that [1]. A lot of the basis from this post comes from my experiment in writing Javascript that compiles to Rust! [1] https://github.com/willcrichton/lia

My first thought is: Neat! Languages with different grammars, syntax, and libraries have different expressivities; my first thought is always compiler implementation in OCaml. I would love, for example, to (effortlessly!) dip into OCaml or Haskell while writing a high-performance C++ program, for example. I am very intrigued by Lia [0] as an example for how languages can be embedded inside of one another for useful effects. See Will Crichton's great blog post for more [1]. However, I am wondering why Python and PHP were chosen. I can't think of a compelling use for having both languages simultaneously. They are both dynamic scripting languages with similar design objectives. [0] https://github.com/willcrichton/lia [1] http://notes.willcrichton.net/the-coming-age-of-the-polyglot...