TODO.md

Missing features

• R7RS multi-line comments
• R7RS "datum comments"
• Proper string escape syntax, instead of using JSON's rules
• Serde support
• Syntactic sugar for quote, quasiquote, unquote and unquote-splicing
• Support for characters
• Support for vectors
• Support for byte vectors
• Pretty-printing

The sexp Macro

• Quote syntactic sugar
• Unquote-splicing
• Improve error reporting

Lisp dialects

• Scheme (R6RS, R7RS, Guile/Racket extensions)
• Emacs Lisp
• Common Lisp

Numbers

• Different bases
• Scheme numeric tower (complex numbers, rationals, bignums)
• NaNs and infinities (fixup from implementations vs. from_f64)

Architectural considerations

• Split off the low-level part of the parser into its own module (or even crate), using an event-based API. This should allow for efficient implementation of the Serde deserializer. See yaml_rust::parser::Parser for an example and serde_yaml for an example of how that might look like. A reason for splitting this functionality into its own crate might be that the functionality can the re-used for, say, a Lisp implementation which does not use lexpr::Value as data representation, and hence does not need all the related code in lexpr. The same reasoning might apply to the printing API.

  It might be a good idea to code some benchmarks before doing the restructuring to ensure it doesn't affect performance too much -- let's put that "zero-cost abstractions" concept to the test!