CL-2DSYNTAX

The cl-2dsyntax is an indentation-sensitive reader system. Published in the public domain. Because lispers read the code by indentation and not by parentheses, I've decided to write a reader macro for this.

It's up to you when to use this, I'm going to use it in a dumb editor such the Notepad (when I can't choose better).

Download

The asdf-installable package: cl-2dsyntax.tar.gz

Usage

After evaluation of the (enable-syntax) form, the reader macro is hooked on the char #\!.

After #\! it reads input until #\Newline followed by non #\Space character. If the input is only one line it's transformed into list, which is evaluated.

The form:

!+ 1 2 3

transforms into:

(+ 1 2 3)

The first line is skipped if it's empty:

!
* 1
  2
  3

Multi-line input is transformed in this way:

• If a nestation occurs on the next line, the currrent line and the nested rest is wrapped into a list.
• If the nested invocation of reader macro is used it's handled slightly different: all what's nested is extracted and then it's handled the same way, but the case when more than one form on the same main level of indentation occur then every form is transformed separately and afterwards are wrapped in a list together.

!let !!a "Hello "
      !b "world!"
 !concatenate 'string a b

or:

!let !a
         "Hello "
      (b "world!")
 concatenate
  'string a b

Samples

A factorial function:

!defun fact !n
  if !zerop n
    1
    !* n !fact !1- n

or another version:

!defun fact (n)
  if (zerop n)
    1
    * n
      fact
        1-
          n

Implementation of the once-only macro:

!defmacro once-only !(&rest names) &body body
  let !!gensyms !loop for n in names collect !gensym
   `!let !,@!loop for g in gensyms collect `!,g !gensym
      `!let !,,@!loop for g in gensyms for n in names collect ``!,,g ,,n
         ,!let !,@!loop for n in names for g in gensyms collect `!,n ,g
            ,@body