[Chicken-hackers] [PATCH] fix reader for keywords starting with a digit or "."

[Felix]

Detect keywords that start with numbers or dot correctly.

This was reported by Moritz and Christian and was caused by
using the wrong internal token-reader function when a token
started with a digit or #\. - this implies the #\. inside
a dotted list.

Fixes #922.


cheers,
felix

>From 5bb4a767efa449f721e1c282aa6896462e664773 Mon Sep 17 00:00:00 2001
From: felix <address@hidden>
Date: Wed, 12 Sep 2012 22:25:54 +0200
Subject: [PATCH] Detect keywords that start with numbers or dot correctly.

This was reported by Moritz and Christian and was caused by
using the wrong internal token-reader function when a token
started with a digit or #\. - this implies the #\. inside
a dotted list.
---
 library.scm             |   58 ++++++++++++++++++++++++++--------------------
 tests/library-tests.scm |    6 +++++
 2 files changed, 39 insertions(+), 25 deletions(-)

diff --git a/library.scm b/library.scm
index 76eb046..bb30f39 100644
--- a/library.scm
+++ b/library.scm
@@ -2553,15 +2553,20 @@ EOF
                                            (starting-line "missing list 
terminator")
                                            end) ) ]
                                        [else
-                                        (let* ((tok (##sys#string-append "." 
(r-token)))
-                                               (n (and (char-numeric? c2) 
-                                                       (##sys#string->number 
tok)))
-                                               (val (or n (build-symbol tok))) 
-                                               (node (cons val '())) )
-                                          (if first 
-                                              (##sys#setslot last 1 node)
-                                              (set! first node) )
-                                          (loop node) ) ] ) ) )
+                                        (r-xtoken
+                                         (lambda (tok kw)
+                                           (let* ((tok (##sys#string-append 
"." tok))
+                                                  (val
+                                                   (if kw
+                                                       (build-keyword tok)
+                                                       (or (and (char-numeric? 
c2) 
+                                                                
(##sys#string->number tok))
+                                                           (build-symbol 
tok))))
+                                                  (node (cons val '())) )
+                                             (if first 
+                                                 (##sys#setslot last 1 node)
+                                                 (set! first node) )
+                                             (loop node) ))) ] ) ) )
                               (else
                                (let ([node (cons (readrec) '())])
                                  (if first
@@ -2582,22 +2587,25 @@ EOF
          
          (define (r-number radix exactness)
            (set! rat-flag #f)
-           (let ((tok (r-token)))
-             (cond
-               ((string=? tok ".")
-                 (##sys#read-error port "invalid use of `.'"))
-               ((and (fx> (##sys#size tok) 0) (char=? (string-ref tok 0) #\#))
-                 (##sys#read-error port "unexpected prefix in number syntax" 
tok))
-               (else
-                 (let ((val (##sys#string->number tok (or radix 10) 
exactness)) )
-                   (cond (val
-                          (when (and (##sys#inexact? val) (not (eq? exactness 
'i)) rat-flag)
-                            (##sys#read-warning
-                             port
-                             "cannot represent exact fraction - coerced to 
flonum" tok) )
-                          val)
-                         (radix (##sys#read-error port "illegal number syntax" 
tok))
-                         (else (build-symbol tok)) ) ) ) ) ) )
+           (r-xtoken
+            (lambda (tok kw)
+              (cond (kw
+                     (let ((s (build-keyword tok)))
+                       (info 'symbol-info s (##sys#port-line port)) ))
+                    ((string=? tok ".")
+                     (##sys#read-error port "invalid use of `.'"))
+                    ((and (fx> (##sys#size tok) 0) (char=? (string-ref tok 0) 
#\#))
+                     (##sys#read-error port "unexpected prefix in number 
syntax" tok))
+                    (else
+                     (let ((val (##sys#string->number tok (or radix 10) 
exactness)) )
+                       (cond (val
+                              (when (and (##sys#inexact? val) (not (eq? 
exactness 'i)) rat-flag)
+                                (##sys#read-warning
+                                 port
+                                 "cannot represent exact fraction - coerced to 
flonum" tok) )
+                              val)
+                             (radix (##sys#read-error port "illegal number 
syntax" tok))
+                             (else (build-symbol tok)) ) ) ) ) ) ))
 
          (define (r-number-with-exactness radix)
            (cond [(char=? #\# (##sys#peek-char-0 port))
diff --git a/tests/library-tests.scm b/tests/library-tests.scm
index c986ef1..c385c1b 100644
--- a/tests/library-tests.scm
+++ b/tests/library-tests.scm
@@ -300,6 +300,12 @@
 (assert (string=? ":" (symbol->string (with-input-from-string ":||" read))))
 (assert-fail (with-input-from-string "#:" read))
 
+(assert (keyword? (with-input-from-string "42:" read)))
+(assert (keyword? (with-input-from-string ".:" read)))
+
+(assert (equal? (cons 1 2) (with-input-from-string "(1 . 2)" read)))
+(assert (every keyword? (with-input-from-string "(42: abc: .: #:: ::)" read)))
+
 
 ;;; setters
 
-- 
1.7.0.4