Add: Timestamp selectors :on a number

This ought to be pretty thorough now.

README.org

@@ -207,15 +207,22 @@ Arguments are listed next to predicate names, where applicable.
 :TOC:      ignore
 :END:
 
-All of these selectors take optional keyword arguments ~:from~, ~:to:~, and ~:on~.  If ~:from~, return non-nil if entry has a timestamp on or after ~:from~.  If ~:to~, return non-nil if entry has a timestamp on or before ~:to~.  If ~:on~, return non-nil if entry has a timestamp on date ~:on~.  Argument values should be either ~ts~ structs, or strings parseable by ~parse-time-string~ which may omit the time value.
+All of these selectors take optional keyword arguments ~:from~, ~:to:~, and ~:on~:
 
++  If ~:from~, return non-nil if entry has a timestamp on or after ~:from~.
++  If ~:to~, return non-nil if entry has a timestamp on or before ~:to~.
++  If ~:on~, return non-nil if entry has a timestamp on date ~:on~.
+
+Argument values should be either a number of days (positive to look forward, or negative to look backward), a ~ts~ struct, or a string parseable by ~parse-time-string~ which may omit the time value.
+
+*Selectors:*
 +  ~ts~ :: Return non-nil if current entry has a timestamp in given period.  If no arguments are specified, return non-nil if entry has any timestamp.
 +  ~ts-active~ :: Like ~ts~, but only matches active timestamps.
 +  ~ts-a~ :: Like ~ts~, but only matches active timestamps.
 +  ~ts-inactive~ :: Like ~ts~, but only matches inactive timestamps.
 +  ~ts-i~ :: Like ~ts~, but only matches inactive timestamps.
 
-The following selectors can also take a single argument, a number, which looks backward or forward a number of days.  The number can also be negative to invert the direction.
+The following selectors, in addition to the keyword arguments, can also take a single argument, a number, which looks backward or forward a number of days.  The number can be negative to invert the direction.
 
 *Backward-looking:*
 +  ~clocked~ :: Return non-nil if current entry was clocked in given period.  If no arguments are specified, return non-nil if entry was clocked at any time.  Note: Clock entries are expected to be clocked out.  Currently clocked entries (i.e. with unclosed timestamp ranges) are ignored.

org-ql.el

@@ -313,14 +313,45 @@ Replaces bare strings with (regexp) selectors, and appropriate
                                      (ts-apply :hour 23 :minute 59 :second 59))))
                         `(,pred :to ,to)))
                      (`(,(and pred (or 'deadline 'scheduled 'planning))
-                        ,(and type (or :from :to :on))
+                        ,(and direction (or :from :to :on))
                         ,(and num-days (pred numberp)))
                       (let ((target (->> (ts-now)
                                          (ts-adjust 'day num-days)
                                          (ts-apply :hour 23 :minute 59 :second 59))))
-                        `(,pred ,type ,target)))
+                        `(,pred ,direction ,target)))
+                     (`(,(and pred (or 'ts 'ts-a 'ts-i 'ts-active 'ts-inactive))
+                        ,(and direction (or :from :to))
+                        ,(and num-days (pred numberp)))
+                      (-let* ((type (pcase-exhaustive pred
+                                      ((or 'ts-i 'ts-inactive) 'inactive)
+                                      ((or 'ts-a 'ts-active) 'active)
+                                      ('ts 'both)))
+                              ((hour minute second) (pcase-exhaustive direction
+                                                      (:from '(0 0 0))
+                                                      (:to '(23 59 59))))
+                              (ts (->> (ts-now)
+                                       (ts-adjust 'day num-days)
+                                       (ts-apply :hour hour :minute minute :second second))))
+                        `(ts :type ,type ,direction ,ts)))
+                     (`(,(and pred (or 'ts 'ts-a 'ts-i 'ts-active 'ts-inactive))
+                        :on
+                        ,(and num-days (pred numberp)))
+                      ;; This rule is only for :on, because we must provide both :from and :to
+                      ;; timestamps to the (ts) selector for the --query-predicate function.
+                      (-let* ((type (pcase-exhaustive pred
+                                      ((or 'ts-i 'ts-inactive) 'inactive)
+                                      ((or 'ts-a 'ts-active) 'active)
+                                      ('ts 'both)))
+                              (from (->> (ts-now)
+                                         (ts-adjust 'day num-days)
+                                         (ts-apply :hour 0 :minute 0 :second 0)))
+                              (to (->> (ts-now)
+                                       (ts-adjust 'day num-days)
+                                       (ts-apply :hour 23 :minute 59 :second 59))))
+                        `(ts :type ,type :from ,from :to ,to)))
                      (`(,(or 'ts-active 'ts-a) . ,rest) `(ts :type active ,@rest))
                      (`(,(or 'ts-inactive 'ts-i) . ,rest) `(ts :type inactive ,@rest))
+                     ;; Any other form: passed through unchanged.
                      (_ element))))
     (rec query)))
 

tests/test-org-ql.el

@@ -529,17 +529,32 @@ RESULTS should be a list of strings as returned by
           (org-ql-expect ((ts :from "2019-06-08" :type active))
             nil))
 
+        (org-ql-it ":from a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts :from 5))
+              '("Take over the universe" "Visit Mars" "Visit the moon" "Renew membership in supervillain club" "Internet" "Spaceship lease" "Rewrite Emacs in Common Lisp"))))
+
         (org-ql-it ":to a timestamp"
           (org-ql-expect ((ts :to "2019-06-10" :type active))
             '("Take over the universe" "Take over the world" "Skype with president of Antarctica" "Visit Mars" "Visit the moon" "Practice leaping tall buildings in a single bound" "Renew membership in supervillain club" "Order a pizza" "Get haircut" "Internet" "Spaceship lease" "Fix flux capacitor" "/r/emacs" "Shop for groceries" "Rewrite Emacs in Common Lisp"))
           (org-ql-expect ((ts :to "2017-07-04" :type active))
             '("Skype with president of Antarctica")))
 
+        (org-ql-it ":to a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts :to -1))
+              '("Skype with president of Antarctica"))))
+
         (org-ql-it ":on a timestamp"
           (org-ql-expect ((ts :on "2017-07-05" :type active))
             '("Practice leaping tall buildings in a single bound" "Order a pizza" "Get haircut" "Fix flux capacitor" "/r/emacs" "Shop for groceries" "Rewrite Emacs in Common Lisp"))
           (org-ql-expect ((ts :on "2019-06-09" :type active))
-            nil)))
+            nil))
+
+        (org-ql-it ":on a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts-active :on 2))
+              '("Take over the world")))))
 
       (describe "inactive"
 
@@ -553,17 +568,32 @@ RESULTS should be a list of strings as returned by
           (org-ql-expect ((ts :from "2019-06-08" :type inactive))
             nil))
 
+        (org-ql-it ":from a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts-i :from 5))
+              '("Visit the moon" "Rewrite Emacs in Common Lisp"))))
+
         (org-ql-it ":to a timestamp"
           (org-ql-expect ((ts :to "2019-06-10" :type inactive))
             '("Test data" "Visit the moon" "Learn universal sign language" "Rewrite Emacs in Common Lisp"))
           (org-ql-expect ((ts :to "2017-07-04" :type inactive))
             'nil))
 
+        (org-ql-it ":to a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts-i :to 5))
+              '("Test data" "Learn universal sign language"))))
+
         (org-ql-it ":on a timestamp"
           (org-ql-expect ((ts :on "2017-07-05" :type inactive))
             '("Test data" "Learn universal sign language"))
           (org-ql-expect ((ts :on "2019-06-09" :type inactive))
-            nil)))
+            nil))
+
+        (org-ql-it ":on a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts-inactive :on 19))
+              '("Visit the moon" "Rewrite Emacs in Common Lisp")))))
 
       (describe "both"
 
@@ -584,6 +614,11 @@ RESULTS should be a list of strings as returned by
           (org-ql-expect ((ts :from "2019-06-08" :type both))
             nil))
 
+        (org-ql-it ":from a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts :from -5))
+              '("Test data" "Take over the universe" "Take over the world" "Skype with president of Antarctica" "Visit Mars" "Visit the moon" "Practice leaping tall buildings in a single bound" "Renew membership in supervillain club" "Learn universal sign language" "Order a pizza" "Get haircut" "Internet" "Spaceship lease" "Fix flux capacitor" "/r/emacs" "Shop for groceries" "Rewrite Emacs in Common Lisp"))))
+
         (org-ql-it ":to a timestamp"
           (org-ql-expect ((ts :to "2017-07-06"))
             '("Test data" "Skype with president of Antarctica" "Practice leaping tall buildings in a single bound" "Learn universal sign language" "Order a pizza" "Get haircut" "Fix flux capacitor" "/r/emacs" "Shop for groceries" "Rewrite Emacs in Common Lisp"))
@@ -594,6 +629,11 @@ RESULTS should be a list of strings as returned by
           (org-ql-expect ((ts :to "2017-07-04" :type both))
             '("Skype with president of Antarctica")))
 
+        (org-ql-it ":to a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts :to 5))
+              '("Test data" "Take over the world" "Skype with president of Antarctica" "Practice leaping tall buildings in a single bound" "Renew membership in supervillain club" "Learn universal sign language" "Order a pizza" "Get haircut" "Fix flux capacitor" "/r/emacs" "Shop for groceries" "Rewrite Emacs in Common Lisp"))))
+
         (org-ql-it ":on a timestamp"
           (org-ql-expect ((ts :on "2017-07-05"))
             '("Test data" "Practice leaping tall buildings in a single bound" "Learn universal sign language" "Order a pizza" "Get haircut" "Fix flux capacitor" "/r/emacs" "Shop for groceries" "Rewrite Emacs in Common Lisp"))
@@ -602,7 +642,12 @@ RESULTS should be a list of strings as returned by
           (org-ql-expect ((ts :on "2019-06-09"))
             nil)
           (org-ql-expect ((ts :on "2019-06-09" :type both))
-            nil))))
+            nil))
+
+        (org-ql-it ":on a number of days"
+          (org-ql-then
+            (org-ql-expect ((ts :on 5))
+              '("Renew membership in supervillain club"))))))
 
     (describe "Compound queries"