2013-09-12: start of a wisp-reader. Unfinished and currently broken.

start of a wisp-reader. Unfinished and currently broken.

diff --git a/wisp-reader.w b/wisp-reader.w
new file mode 100644
--- /dev/null
+++ b/wisp-reader.w
@@ -0,0 +1,75 @@
+#!/home/arne/wisp/wisp-multiline.sh 
+; !#
+;;
+;; Implement wisp in guile
+;;
+;; -Author: Arne Babenhauserheide
+
+; adapted from guile-sweet: https://gitorious.org/nacre/guile-sweet/source/ae306867e371cb4b56e00bb60a50d9a0b8353109:sweet/common.scm
+
+
+; adapted from spec.scm: https://gitorious.org/nacre/guile-sweet/source/ae306867e371cb4b56e00bb60a50d9a0b8353109:sweet/spec.scm
+(define-module (language scheme spec)
+  #:use-module (system base compile)
+  #:use-module (system base language)
+  #:use-module (language scheme compile-tree-il)
+  #:use-module (language scheme decompile-tree-il)
+  #:export (scheme))
+
+;;;
+;;; Language definition
+;;;
+
+(define-language wisp
+  #:title "Wisp Scheme Syntax"
+  #:reader (lambda (port env)
+             (wisp-read port))
+  #:compilers `((tree-il . ,compile-tree-il))
+  #:decompilers `((tree-il . ,decompile-tree-il))
+  #:evaluator (lambda (x module) (primitive-eval x))
+  #:printer write
+  #:make-default-environment
+  (lambda ()
+    ;; Ideally we'd duplicate the whole module hierarchy so that `set!',
+    ;; `fluid-set!', etc. don't have any effect in the current environment.
+    (let ((m (make-fresh-user-module)))
+      ;; Provide a separate `current-reader' fluid so that
+      ;; compile-time changes to `current-reader' are
+      ;; limited to the current compilation unit.
+      (module-define! m 'current-reader (make-fluid))
+      ;; Default to `simple-format', as is the case until
+      ;; (ice-9 format) is loaded. This allows
+      ;; compile-time warnings to be emitted when using
+      ;; unsupported options.
+      (module-set! m 'format simple-format)
+      m)))
+
+; adapted from sugar.scm: https://gitorious.org/nacre/guile-sweet/source/ae306867e371cb4b56e00bb60a50d9a0b8353109:sweet/sugar.scm
+
+(define* (wisp-read #:optional (port (current-input-port)))
+  ; Read single complete I-expression.
+  (let* ((indentation (list->string (accumulate-hspace port)))
+         (c (peek-char port)))
+    (cond
+     ((eof-object? c) c) ; EOF - return it, we're done.
+     ((eqv? c #\; ) ; comment - consume and see what's after it.
+      (let ((d (consume-to-eol port)))
+        (cond
+         ((eof-object? d) d) ; If EOF after comment, return it.
+         (#t
+          (read-char port) ; Newline after comment. Consume NL
+          (sugar-read port))))) ; and try again
+     ((eqv? c #\newline)
+      (read-char port) ; Newline (with no preceding comment).
+      (sugar-read port)) ; Consume and again
+     (#t
+                                        ; TODO: Handle (> (string-length indentation) 0)
+      (let* ((read (readblock-clean "" port))
+             (level (car read))
+             (block (cdr read)))
+        (cond
+         ((eq? block '.)
+          '())
+         (#t
+          block)))))))
+