document: Index boolean terms.

Metadata that will be used in boolean filtering should be indexed as
boolean terms, not as free text. This also results in the happy
coincidence that we no longer need a specialized
document-term-generator generic method for <issue> and <commit>.

* tissue/document.scm (document-boolean-terms): New public generic
function.
(document-term-generator): Use document-boolean-terms.
* tissue/issue.scm (document-boolean-terms): New generic method.
(document-term-generator): Delete generic method.
* tissue/commit.scm (document-boolean-terms): New generic method.
(document-term-generator): Delete generic method.

3 files changed, 24 insertions, 20 deletions

diff --git a/tissue/commit.scm b/tissue/commit.scm
index 30d07b7..10dc436 100644
--- a/tissue/commit.scm
+++ b/tissue/commit.scm
@@ -42,16 +42,15 @@
   "Return the ID term for DOCUMENT."
   (string-append "Qcommit." (commit-hash commit)))
 
+(define-method (document-boolean-terms (commit <commit>))
+  "Return the boolean terms in COMMIT."
+  (list (string-append "Qcommit." (commit-hash commit))
+        (string-append "A" (doc:commit-author commit))))
+
 (define-method (document-recency-date (commit <commit>))
   "Return a date representing the recency of DOCUMENT"
   (doc:commit-author-date commit))
 
-(define-method (document-term-generator (commit <commit>))
-  "Return a term generator indexing COMMIT."
-  (let ((term-generator (next-method)))
-    (index-person! term-generator (doc:commit-author commit) "A")
-    term-generator))
-
 (define-method (document-snippet-source-text (commit <commit>))
   "Return the source text for COMMIT from which to extract a search
 result snippet."
diff --git a/tissue/document.scm b/tissue/document.scm
index ecdabc3..48d82cc 100644
--- a/tissue/document.scm
+++ b/tissue/document.scm
@@ -36,6 +36,7 @@
             document-web-uri
             document-type
             document-id-term
+            document-boolean-terms
             document-text
             document-recency-date
             document-term-generator
@@ -142,6 +143,10 @@ that operates on a copy of OBJECT. It does not mutate OBJECT."
   (string-trim-both (symbol->string (class-name (class-of document)))
                     (char-set #\< #\>)))
 
+(define-method (document-boolean-terms (document <document>))
+  "Return the boolean terms in DOCUMENT."
+  (list))
+
 (define-method (document-term-generator (document <document>))
   "Return a term generator for DOCUMENT. The returned term generator has
 indexed the type and text of the document. If further free text is to
@@ -153,7 +158,9 @@ and further text, increase-termpos! must be called before indexing."
           #:document (make-document
                       #:data (call-with-output-string
                                (cut write (object->scm document) <>))
-                      #:terms `((,(document-id-term document) . 0))
+                      #:terms (map (cut cons <> 0)
+                                   (cons (document-id-term document)
+                                         (document-boolean-terms document)))
                       ;; This serialization of the recency date gets
                       ;; the timezone ordering wrong. TODO: Replace it
                       ;; with sortable-serialise once it is working in
diff --git a/tissue/issue.scm b/tissue/issue.scm
index 3fb21cc..23625fa 100644
--- a/tissue/issue.scm
+++ b/tissue/issue.scm
@@ -58,19 +58,17 @@
   (tasks #:accessor issue-tasks #:init-keyword #:tasks)
   (completed-tasks #:accessor issue-completed-tasks #:init-keyword #:completed-tasks))
 
-(define-method (document-term-generator (issue <issue>))
-  "Return a term generator indexing ISSUE."
-  (let ((term-generator (next-method)))
-    (index-person! term-generator (file-document-creator issue) "A")
-    (index-person! term-generator (file-document-last-updater issue) "XA")
-    (for-each (cut index-person! term-generator <> "XI")
-              (issue-assigned issue))
-    (for-each (cut index-text! term-generator <> #:prefix "K")
-              (issue-keywords issue))
-    (index-text! term-generator
-                 (if (issue-open? issue) "open" "closed")
-                 #:prefix "XS")
-    term-generator))
+(define-method (document-boolean-terms (issue <issue>))
+  "Return the boolean terms in ISSUE."
+  (append (list (string-append "A" (file-document-creator issue))
+                (string-append "XA" (file-document-last-updater issue))
+                (string-append "XS" (if (issue-open? issue)
+                                        "open" "closed")))
+          (map (cut string-append "XI" <>)
+               (issue-assigned issue))
+          (map (cut string-append "K" <>)
+               (issue-keywords issue))
+          (next-method)))
 
 (define-method (print (issue <issue>) mset port)
   "Print ISSUE, an <issue> object, in search results."