mu-scm: add support for references

Message method + test + docs.

scm/mu-scm-test.scm

@@ -70,13 +70,26 @@
 
     (test-end "test-message-full")))
 
-(define (test-misc)
+(define (test-message-more)
+  (test-begin "test-message-more")
+  (let ((msg (car (mfind "to:dfgh@floppydisk.nl"))))
+    (test-equal "Re: xyz" (subject msg))
+    (test-equal "Mozilla Thunderbird 1.0.7 (X11/20051010)" (header msg "User-Agent"))
+    (test-equal '("439C1136.90504@euler.org" "4399DD94.5070309@euler.org"
+		  "20051209233303.GA13812@gauss.org" "439B41ED.2080402@euler.org"
+		  "439A1E03.3090604@euler.org" "20051211184308.GB13513@gauss.org")
+      (references msg)))
+  (test-end "test-message-more"))
+
+(define (test-options)
+  (test-begin "test-options")
   (let ((opts (options)))
     (test-assert (>= (length opts) 4))
     (test-equal (assoc-ref opts 'quiet) #f)
     (test-equal (assoc-ref opts 'debug) #f)
     (test-equal (assoc-ref opts 'verbose) #f)
-    (test-equal (assoc-ref opts 'muhome) #f)))
+    (test-equal (assoc-ref opts 'muhome) #f))
+    (test-end "test-options"))
 
 (define (test-helpers)
   (test-begin "test-helpers")
@@ -96,7 +109,8 @@
       (test-basic-mfind)
       (test-mfind)
       (test-message-full)
-      (test-misc)
+      (test-message-more)
+      (test-options)
       (test-helpers)
 
       (test-end "mu-scm-tests")

scm/mu-scm.scm

@@ -41,6 +41,8 @@
   priority
   subject
 
+  references
+
   language
   size
 
@@ -201,7 +203,7 @@ A symbol, either 'high, 'low or 'normal, or #f if not found."
   (find-field message ':priority))
 
 (define-method (language (message <message>))
-  "Get the ISO-639-1 language code for the message as a symbol, if detected.
+  "Get the ISO-639-1 language code for the MESSAGE as a symbol, if detected.
 Return #f otherwise."
   (let ((lang (find-field message ':language)))
     (if lang
@@ -210,13 +212,21 @@ Return #f otherwise."
 ;; if-let would be nice!
 
 (define-method (size (message <message>))
-  "Get the size of the message in bytes or #f if not available."
+  "Get the size of the MESSAGE in bytes or #f if not available."
   (find-field message ':size))
 
+(define-method (references (message <message>))
+  "Get the list of reference of MESSAGE or #f if not available.
+ with the oldest first and the direct parent as the last one. Note, any
+reference (message-id) will appear at most once, duplicates and
+fake-message-id (see impls) are filtered out. If there are no references, return
+#f."
+  (find-field message ':references))
+
 ;;  Flags.
 
 (define-method (flags (message <message>))
-  "Get the size of the message in bytes or #f if not available."
+  "Get the size of the MESSAGE in bytes or #f if not available."
   (find-field message ':flags))
 
 (define-method (flag? (message <message>) flag)

scm/mu-scm.texi

@@ -624,6 +624,19 @@ For example:
 => #f
 @end lisp
 
+@deffn {Scheme Procedure} references message
+@end deffn
+Get the list of references (message-ids of related messages) for this message.
+This combines the @t{References} and @t{In-Reply-To} fields, from oldest to the
+immediate parent. Returns @code{#f} if there are no references.
+
+@lisp
+(references msg)
+=> ("439C1136.90504@@euler.org" "4399DD94.5070309@@euler.org"
+    "20051209233303.GA13812@@gauss.org" "439B41ED.2080402@@euler.org"
+    439A1E03.3090604@@euler.org" "20051211184308.GB13513@@gauss.org")
+@end lisp
+
 @c @deffn {Scheme Procedure} sexp message
 @c @end deffn
 @c Get the message's s-expression.