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Re: SRFI 105: Curly-infix-expressions

This page is part of the web mail archives of SRFI 105 from before July 7th, 2015. The new archives for SRFI 105 contain all messages, not just those from before July 7th, 2015.

Aubrey Jaffer <agj@xxxxxxxxxxxx>
>  Is the syntax { f(x) } not handled?

As I mentioned earlier, not in straight curly-infix, because that's the role of neoteric-expressions, which I intend to submit as a separate SRFI.  But if people want to support { f(x) } without necessarily supporting f(x) at the outermost level, we could modify curly-infix to do easily, by requiring support for a sequence of neoteric-expressions *inside* a curly-infix expression (recursively).

That would add a little more to the specification, though not much.  Here's an example of how this would modify the current draft curly-infix specification:


A curly-infix list contains, inside {...}, a sequence of 0 or more whitespace-separated neoteric-expressions.

A neoteric-expression is a curly-infix expression, but in addition, given a datum "e":
*   An e(...) maps to (e ...). E.g., f(1 2) &#8658; (f 1 2), exit() &#8658; (exit), and read(. port) &#8658; (read . port).
*   An e{} maps to (e), otherwise, e{...} maps to (e {...}). E.g., f{n - 1} &#8658; (f {n - 1}) &#8658; (f (- n 1)), and g{- x} &#8658; (g (- x)).
*   An e[...] maps to (bracketaccess e ...)

There must be no whitespace between e and the open paired character.  Also, an unprefixed "( . e)" must evaluate as "e".  Unprefixed lists contain a sequence of zero or more whitespace-separated neoteric-expressions, recursively.


With this addition, you *CAN* have:
  {f(x) + 5 + g(x y)}
and even:
  {substring("Hello" 1 3)}

For rationale on the design of neoteric-expressions, see:

--- David A. Wheeler