CL-RTTEMPLATE

The cl-rttemplate is a read-time quotation system. Published in the public domain. It's a template system similar to the quasiquote & unquote facility, however, it operates during the read-time.

I've created this for a need to macroize the commonqt reader macros.

Download

The asdf-installable package: cl-rttemplate.tar.gz

API

• #" reader macro reads from the input until "# sequence is read. The " character toggles quoting and the \ character escapes it.
• #@ is a helper reader macro which works like the splicing unquote ,@. Internally it uses multiple values so if you have an unquoted form which returns multiple values, you can use #n@ where n denotes which single value to use.
• *rt* readtable is active during writing unquoted parts into a string representation at building the whole form which is going to be read.
• enable-syntax function which enables the reader macros and copy the current *readtable* to the *rt*.

Usage

Enable the syntax by (cl-rttemplate:enable-syntax) or (rtt:enable-syntax).

Modify the readtable at yout will, for example: (setf (readtable-case rtt:*rt*) :preserve).

Samples

Simple symbol building:

#"'begin"(expt 3 8)"end"#

The lexical binding is available + an exhibition of the impact of *rt*:

(let ((outer-value '|Hello|))
   #"'(a b " outer-value " \"" outer-value " world!\")"#)

vs.

(setf (readtable-case rtt:*rt*) :preserve)
(let ((outer-value '|Hello|))
   #"'(a b " outer-value " \"" outer-value " world!\")"#)

An example with #@:

#"'(a " #@'(b c d) " e)"#

and:

#"(* " #0@(floor 100 7) " " #1@(floor 25 13) ")"#