Fix: (level) Check number argument for preamble

This allows a query like this:

  (level <= (string-to-number (property PROPERTY)))

to proceed without signaling an error from ORG-QL--QUERY-PREAMBLE.

See #460.

Reported-by: Stewmath <https://github.com/Stewmath>

README.org

@@ -557,6 +557,7 @@ Simple links may also be written manually in either sexp or non-sexp form, like:
 
 *Fixes*
 + Predicate ~property~ when called with argument form ~(property "PROPERTY-NAME" :inherit t)~.  ([[https://github.com/alphapapa/org-ql/issues/460][#460]].  Thanks to [[https://github.com/Stewmath][Stewmath]] for reporting.)
++ Predicate ~level~'s preamble optimizer allows expressions in place of the numeric argument.  (See [[https://github.com/alphapapa/org-ql/issues/460][#460]].  Thanks to [[https://github.com/Stewmath][Stewmath]] for reporting.)
 + Reading of view settings from Org links in upcoming Emacs version.  ([[https://github.com/alphapapa/org-ql/issues/461][#461]].  Thanks to [[https://github.com/snogge][Ola Nilsson]] for help debugging, and for maintaining [[https://github.com/jorgenschaefer/emacs-buttercup][Buttercup]].)
 
 ** 0.8.8

org-ql.el

@@ -1534,7 +1534,8 @@ COMPARATOR may be `<', `<=', `>', or `>='."
                ;; is "h:" while the user is typing.
                (list :regexp (rx bol (1+ "*") " ")
                      :case-fold t))
-              (`(,predicate-names ,comparator-or-num ,num)
+              ((and `(,predicate-names ,comparator-or-num ,num)
+                    (guard (numberp num)))
                (let ((repeat (pcase comparator-or-num
                                ('< `(repeat 1 ,(1- num) "*"))
                                ('<= `(repeat 1 ,num "*"))
@@ -1543,7 +1544,8 @@ COMPARATOR may be `<', `<=', `>', or `>='."
                                ((pred integerp) `(repeat ,comparator-or-num ,num "*")))))
                  (list :regexp (rx-to-string `(seq bol ,repeat " ") t)
                        :case-fold t)))
-              (`(,predicate-names ,num)
+              ((and `(,predicate-names ,num)
+                    (guard (numberp num)))
                (list :regexp (rx-to-string `(seq bol (repeat ,num "*") " ") t)
                      :case-fold t)))
   ;; NOTE: It might be necessary to take into account `org-odd-levels'; see docstring for

org-ql.info

@@ -1089,6 +1089,10 @@ File: README.info,  Node: 089-pre,  Next: 088,  Up: Changelog
      "PROPERTY-NAME" :inherit t)’.  (#460
      (https://github.com/alphapapa/org-ql/issues/460).  Thanks to
      Stewmath (https://github.com/Stewmath) for reporting.)
+   • Predicate ‘level’’s preamble optimizer allows expressions in place
+     of the numeric argument.  (See #460
+     (https://github.com/alphapapa/org-ql/issues/460).  Thanks to
+     Stewmath (https://github.com/Stewmath) for reporting.)
    • Reading of view settings from Org links in upcoming Emacs version.
      (#461 (https://github.com/alphapapa/org-ql/issues/461).  Thanks to
      Ola Nilsson (https://github.com/snogge) for help debugging, and for
@@ -2073,49 +2077,49 @@ Node: Links38939
 Node: Tips39626
 Node: Changelog39950
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-Node: Comparison with Org Agenda searches77206
-Node: org-sidebar78095
-Node: License78374
+Node: 08841801
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+Node: Comparison with Org Agenda searches77453
+Node: org-sidebar78342
+Node: License78621
 
 End Tag Table
 

tests/test-org-ql.el

@@ -636,6 +636,11 @@ with keyword arg NOW in PLIST."
                   :to-equal (list :query t
                                   :preamble (rx bol (repeat 2 4 "*") " ")
                                   :preamble-case-fold t)))
+        (it "with an expression in level number's place"
+          (expect (org-ql--query-preamble '(level <= (string-to-number (property "PROPERTY"))))
+                  :to-equal (list :query '(level <= (string-to-number (property "PROPERTY")))
+                                  :preamble nil
+                                  :preamble-case-fold t)))
         (it "<"
           (expect (org-ql--query-preamble '(level < 3))
                   :to-equal (list :query t