[PATCH] Make `get-datum' conform more closely to R6RS semantics

[Andreas Rottmann <a.rottmann@gmx.at>]

* module/rnrs/io/ports.scm (get-datum): Set reader options to be more
  compatible with R6RS syntax.

  With Guile's default reader options, R6RS hex escape and EOL escape
  behavior is missing.  This change enables the former via the
  `r6rs-hex-escapes' option, and gets us closer to the latter by setting
  `hungry-eol-escapes'.

* test-suite/tests/r6rs-ports.test ("8.2.9 Textual input")["get-datum"]:
  New tests.
---
 module/rnrs/io/ports.scm         |   13 +++++++++++--
 test-suite/tests/r6rs-ports.test |   28 ++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/module/rnrs/io/ports.scm b/module/rnrs/io/ports.scm
index fddb491..6e6a66d 100644
--- a/module/rnrs/io/ports.scm
+++ b/module/rnrs/io/ports.scm
@@ -1,6 +1,6 @@
 ;;;; ports.scm --- R6RS port API                    -*- coding: utf-8 -*-
 
-;;;;	Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
+;;;;	Copyright (C) 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -437,7 +437,16 @@ return the characters accumulated in that port."
   (with-textual-input-conditions port (read-char port)))
 
 (define (get-datum port)
-  (with-textual-input-conditions port (read port)))
+  (with-textual-input-conditions port
+    (let ((saved-options (read-options)))
+      (dynamic-wind
+        (lambda () (read-options '(positions
+                                   keywords #f
+                                   square-brackets
+                                   r6rs-hex-escapes
+                                   hungry-eol-escapes)))
+        (lambda () (read port))
+        (lambda () (read-options saved-options))))))
 
 (define (get-line port)
   (with-textual-input-conditions port (read-line port 'trim)))
diff --git a/test-suite/tests/r6rs-ports.test b/test-suite/tests/r6rs-ports.test
index 46da67f..6a7386e 100644
--- a/test-suite/tests/r6rs-ports.test
+++ b/test-suite/tests/r6rs-ports.test
@@ -719,6 +719,34 @@
       (and (= 3 (get-string-n! port s 6 3))
            (string=? s "Isn't GNU great?"))))
 
+  (with-test-prefix "get-datum"
+    (let ((string->datum (lambda (s) (get-datum (open-input-string s)))))
+      (pass-if "symbol"
+        (eq? (string->datum "foo") 'foo))
+      (pass-if "symbol [starting with colon]"
+        (eq? ':foo (string->datum ":foo")))
+      (pass-if "string"
+        (string=? "foo" (string->datum "\"foo\"")))
+      (pass-if "string [with hex escapes]"
+        (string=? "bar\nA" (string->datum "\"bar\\x0A;\\x41;\"")))
+      (pass-if "string [hungry EOL]"
+        (string=? "bar baz" (string->datum "\"bar \\\n   baz\"")))
+      ;; FIXME: actually, R6RS demands an even more hungry EOL escape
+      ;; than the reader currently implements: also any whitespace
+      ;; between the backslash and the newline should vanish. Currently,
+      ;; the reader barfs on that.
+      (pass-if "string [hungry EOL, space also before newline]"
+        (throw 'unresolved)
+        (string=? "bar baz" (string->datum "\"bar \\  \n   baz\"")))
+      (pass-if "number [decimal]"
+        (= (string->datum "42") 42))
+      (pass-if "number [hexadecimal]"
+        (= (string->datum "#x2A") 42))
+      (pass-if "number [octal]"
+        (= (string->datum "#o0777") 511))
+      (pass-if "number [binary]"
+        (= (string->datum "#b101010") 42))))
+
   (with-test-prefix "read error"
     (pass-if-condition "get-char" i/o-read-error?
       (get-char (make-failing-port)))
-- 
1.7.10.4