Add: Negation in plain queries

README.org

@@ -164,6 +164,7 @@ The command =org-ql-search= also accepts, and the command =helm-org-ql= only acc
 | ~(heading "quoted phrase" "word")~                | ~heading:"quoted phrase",word~                 |
 | ~(and (tags "book" "books") (priority "A"))~      | ~tags:book,books priority:A~                   |
 | ~(src :lang "elisp" :regexps ("defun"))~          | ~src:defun,lang=elisp~ or ~src:lang=elisp,defun~ |
+| ~(and (tags "space") (not (regexp "moon")))~      | ~tags:space !moon~                             |
 | ~(priority >= B)~                                 | ~priority:A,B~                                 |
 
 Note that the =priority= predicate does not support comparators in the non-sexp syntax, so multiple priorities should be passed instead, as seen in the last example.
@@ -375,6 +376,7 @@ Expands into a call to ~org-ql-select~ with the same arguments.  For convenience
 ** 0.4-pre
 
 *Added*
++  Negation of terms in plain queries using ~!~.  For example, ~tags:space !moon~ to exclude entries which contain ~moon~.
 +  Predicates =outline-path= (alias =olp=) and =outline-path-segment= (alias =olps=).
 +  Info manual.
 +  Command ~org-ql-search~ can search files in ~org-directory~; customization options are available in the ~org-ql-search~ group.

org-ql.el

@@ -1487,10 +1487,15 @@ Builds the PEG expression using predicates defined in
 Multiple predicates are combined with BOOLEAN."
          (unless (s-blank-str? input)
            (let* ((query (peg-parse-string
-                          ((query (+ (or (and predicate-with-args `(pred args -- (cons (intern pred) args)))
+                          ((query (+ term
-                                         (and predicate-without-args `(pred -- (list (intern pred))))
-                                         (and plain-string `(s -- (list 'regexp s))))
                                      (opt (+ (syntax-class whitespace) (any)))))
+                           (term (or (and negation (list positive-term)
+                                          ;; This is a bit confusing, but it seems to work.  There's probably a better way.
+                                          `(pred -- (list 'not (car pred))))
+                                     positive-term))
+                           (positive-term (or (and predicate-with-args `(pred args -- (cons (intern pred) args)))
+                                              (and predicate-without-args `(pred -- (list (intern pred))))
+                                              (and plain-string `(s -- (list 'regexp s)))))
                            (plain-string (substring (+ (not (syntax-class whitespace)) (any))))
                            (predicate-with-args (substring predicate) ":" args)
                            (predicate-without-args (substring predicate) ":")
@@ -1500,6 +1505,7 @@ Multiple predicates are combined with BOOLEAN."
                            (keyword (substring (+ (not (or separator "=" "\"" (syntax-class whitespace))) (any))))
                            (quoted-arg "\"" (substring (+ (not (or separator "\"")) (any))) "\"")
                            (unquoted-arg (substring (+ (not (or separator "\"" (syntax-class whitespace))) (any))))
+                           (negation "!")
                            (separator "," ))
                           input 'noerror)))
              ;; Discard the t that `peg-parse-string' always returns as the first

org-ql.info

@@ -339,6 +339,7 @@ Sexp syntax                                         Non-sexp syntax
 ‘(heading "quoted phrase" "word")’                  ‘heading:"quoted phrase",word’
 ‘(and (tags "book" "books") (priority "A"))’        ‘tags:book,books priority:A’
 ‘(src :lang "elisp" :regexps ("defun"))’            ‘src:defun,lang=elisp’ or ‘src:lang=elisp,defun’
+‘(and (tags "space") (not (regexp "moon")))’        ‘tags:space !moon’
 ‘(priority >= B)’                                   ‘priority:A,B’
 
    Note that the priority predicate does not support comparators in the
@@ -695,6 +696,8 @@ File: README.info,  Node: 04-pre,  Next: 031,  Up: Changelog
 ===========
 
 *Added*
+   • Negation of terms in plain queries using ‘!’.  For example,
+     ‘tags:space !moon’ to exclude entries which contain ‘moon’.
    • Predicates outline-path (alias olp) and outline-path-segment (alias
      olps).
    • Info manual.
@@ -980,24 +983,24 @@ Node: org-ql-view-recent-items6452
 Node: org-ql-sparse-tree6936
 Node: Queries7736
 Node: Non-sexp query syntax8578
-Node: Predicates10198
+Node: Predicates10277
-Node: Date/time predicates15312
+Node: Date/time predicates15391
-Node: Functions / Macros17947
+Node: Functions / Macros18026
-Node: Agenda-like views18134
+Node: Agenda-like views18213
-Node: Listing / acting-on results19539
+Node: Listing / acting-on results19618
-Node: Changelog24141
+Node: Changelog24220
-Node: 04-pre24663
+Node: 04-pre24742
-Node: 03125607
+Node: 03125830
-Node: 0325805
+Node: 0326028
-Node: 02328778
+Node: 02329001
-Node: 02229004
+Node: 02229227
-Node: 02129270
+Node: 02129493
-Node: 0229467
+Node: 0229690
-Node: 0133500
+Node: 0133723
-Node: Notes33599
+Node: Notes33822
-Node: Comparison with Org Agenda searches33761
+Node: Comparison with Org Agenda searches33984
-Node: org-sidebar34632
+Node: org-sidebar34855
-Node: License34911
+Node: License35134
 
 End Tag Table
 

tests/test-org-ql.el

@@ -231,6 +231,17 @@ RESULTS should be a list of strings as returned by
 
     ;; TODO: Other predicates.
 
+    (it "Negated terms"
+      (expect (org-ql--plain-query "todo: !todo:CHECK,SOMEDAY")
+              :to-equal '(and (todo) (not (todo "CHECK" "SOMEDAY"))))
+      (expect (org-ql--plain-query "!todo:CHECK,SOMEDAY todo:")
+              :to-equal '(and (not (todo "CHECK" "SOMEDAY")) (todo)))
+      (expect (org-ql--plain-query "tags:universe !moon")
+              :to-equal '(and (tags "universe") (not (regexp "moon"))))
+      (expect (org-ql--plain-query "!moon tags:universe")
+              :to-equal '(and (not (regexp "moon")) (tags "universe")))
+      (expect (org-ql--plain-query "mars !ts:on=today")
+              :to-equal '(and (regexp "mars") (not (ts :on "today")))))
     (it "Regexp predicates"
       (expect (org-ql--plain-query "scheduled")
               ;; No colon after keyword, so not a predicate query.