get-csv: bugfix: return nil on EOF.

* stream.c (get_csv): Let's add a new state init. If get_char
returns nil and we are in the init state, let's bail to a
nil return. While we are at it, let's not allocate the record
or string until we read at least one character. If we read
a character in the init state, let's allocate those two
objects, and then change to the rfield state and fall through
to it to handle the character.

* tests/010/csv.tl: Fix one incorrect test: (tocsv "") now
returns nil, as it should. Add tests for multiple record
extraction, also covering missing line termination on the last
record as well as CR-LF termination.

* txr.1: Documented nil return conditions.

1 files changed, 23 insertions, 1 deletions

diff --git a/tests/010/csv.tl b/tests/010/csv.tl
index 6c93b6c8..d8561c8c 100644
--- a/tests/010/csv.tl
+++ b/tests/010/csv.tl
@@ -13,7 +13,7 @@
                        data expected))))
 
 (mtest-csv
-  "" #("")
+  "" nil
   "," #("" "")
   ",," #("" "" ""))
 
@@ -183,3 +183,25 @@
   #("a\nb" "c#d" "e,f") "#a\nb#,#c##d#,#e,f#\n"
   #("a\n#,b") "#a\n##,b#\n"
   #("a#\n,b\n") "#a##\n,b\n#\n")
+
+(mtest
+  (with-in-string-stream (s "a,b,c\nd,e,f\r\n") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("a" "b" "c") #("d" "e" "f") nil)
+  (with-in-string-stream (s "a,b,c\nd,e,f\n") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("a" "b" "c") #("d" "e" "f") nil)
+  (with-in-string-stream (s "a,b,c\nd,e,f") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("a" "b" "c") #("d" "e" "f") nil)
+  (with-in-string-stream (s "a,b,c\r\n") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("a" "b" "c") nil nil)
+  (with-in-string-stream (s "a,b,c\n") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("a" "b" "c") nil nil)
+  (with-in-string-stream (s "a,b,c") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("a" "b" "c") nil nil)
+  (with-in-string-stream (s "") (list (get-csv s) (get-csv s) (get-csv s)))
+  (nil nil nil)
+  (with-in-string-stream (s "\r") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("\r") nil nil)
+  (with-in-string-stream (s "\r\n") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("") nil nil)
+  (with-in-string-stream (s "\n") (list (get-csv s) (get-csv s) (get-csv s)))
+  (#("") nil nil))