I doubt that SRFI 49, or any other proposal I've seen online, has been battle-tested.
I've written thousands of lines of Scheme using my own preprocessor, and it's my favorite code to look at. I prefer Haskell, for incredible ease of parallelism and a deeper mathematical foundation.
The two features I look for in a reduced parenthesis syntax (like looking for the bone marrow in a beef stew recipe) are:
1. Some constructions begin doubly parenthesized. One needs a symbol to represent the missing object one parenthesis in. I use $.
2. One can write more expressive lines with a flavor of open paren that autocloses at the end of the line. I use |.
I've written thousands of lines of Scheme using my own preprocessor, and it's my favorite code to look at. I prefer Haskell, for incredible ease of parallelism and a deeper mathematical foundation.
The two features I look for in a reduced parenthesis syntax (like looking for the bone marrow in a beef stew recipe) are:
1. Some constructions begin doubly parenthesized. One needs a symbol to represent the missing object one parenthesis in. I use $.
2. One can write more expressive lines with a flavor of open paren that autocloses at the end of the line. I use |.