[elpa] externals/num3-mode 4610fc7eb2: Replace string regex by the use of ‘rx’

[Michał Nazarewicz]

branch: externals/num3-mode
commit 4610fc7eb2a0dd0b01bf4d9574b598ba6515a4ea
Author: Michal Nazarewicz <mina86@mina86.com>
Commit: Michal Nazarewicz <mina86@mina86.com>

    Replace string regex by the use of ‘rx’
    
    * num3-mode.el (num3--number-re): Replace concatenation of string
    regular expressions by the use of ‘rx’ form.  This allows the code to
    be indented and commented to dramatically improve readability and
    hopefully make further editions easier.
---
 num3-mode.el | 48 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 11 deletions(-)

diff --git a/num3-mode.el b/num3-mode.el
index 87d8a57b01..fa5cab41bd 100644
--- a/num3-mode.el
+++ b/num3-mode.el
@@ -108,17 +108,43 @@ the (place where) decimal point (would be) is."
   ;; group them both in four-digit groups.  There’s no explicit support for
   ;; octal numbers because we just use logic for a decimal number, i.e. the 
same
   ;; grouping.
-  (eval-when-compile
-    (concat
-         "#[xX]\\(?1:[[:xdigit:]]+\\)"       ; 1 = hexadecimal
-      "\\|0[xX]\\(?1:[[:xdigit:]]+\\)?"      ; 1 - hexadecimal
-              "\\(?:\\.\\(?4:[[:xdigit:]]+\\)" ; 4 - hex fraction
-                "[pP][-+]?\\(?2:[0-9]+\\)\\)?" ; 2 - decimal (power)
-      "\\|[0#][bB]\\(?1:[01]+\\)"            ; 1 = binary
-      "\\|\\(?1:\\b\\(?:[0-9]+[a-fA-F]\\|"   ; 1 = hexadecimal w/o prefix
-                "[a-fA-F]+[0-9]\\)[[:xdigit:]]*\\b\\)"
-      "\\|\\(?2:[0-9]+\\)"                   ; 2 = decimal
-      "\\|\\.\\(?3:[0-9]+\\)")))             ; 3 = fraction
+  (rx
+   (or
+    ;; ‘#x1234’
+    (seq ?# (in "xX") (submatch-n 1 (+ (in hex)))) ; 1 - hexadecimal integer
+    ;; ‘0x1234’ or ‘0x1234.5678p±9’.  Hexadecimal floating point numbers
+    ;; require exponent to be present.  ‘0x1234.5678’ are two separate
+    ;; numbers with a dot between them.
+    (seq ?0 (in "xX") (submatch-n 1 (* (in hex)))  ; 1 - hexadecimal integer
+         (? ?. (submatch-n 4 (+ (in hex)))         ; 4 - hexadecimal fraction
+            (in "pP") (? (in "-+"))
+            (submatch-n 2 (+ (in num)))))          ; 2 - decimal int (power)
+    ;; ‘0b1010’ or ‘#b1010’.  Binary numbers use the same group as hexadecimal
+    ;; numbers as they also use grouping of four when highlighted.  Note that
+    ;; this group must be before we match unprefixed hexadecimal numbers.
+    (seq (in "0#") (in "bB")
+         (submatch-n 1 (+ (in "01"))))             ; 1 - binary integer
+    ;; ‘1234abcd’, i.e. hexadecimal number w/o prefix.  There are a few things
+    ;; we want to watch out for:
+    ;; - the match must not be part of a word since we don’t want to match leet
+    ;;   speak or parts of usernames,
+    ;; - the match must contain at least one decimal digits since we don’t want
+    ;;   to match words which happen to match [a-f]*,
+    ;; - the match must contain at least on of non-decimal hexadecimal digits 
or
+    ;;   else it’s just a decimal integer and
+    ;; - the match must not start with ‘0b’ and contain only ones and zeros
+    ;;   since that’s binary number.  Note that we actually do nothing to
+    ;;   prevent binary numbers from matching.  Instead we rely upon those 
cases
+    ;;   being caught by previous cases.
+    (submatch-n 1                                  ; 1 - hexadecimal integer
+                word-boundary
+                (or (seq (+ (in num)) (in "a-fA-F"))
+                    (seq (+ (in "a-fA-F")) (in num)))
+                (* (in hex))
+                word-boundary)
+    ;; ‘1234’
+    (submatch-n 2 (+ (in num)))                    ; 2 - decimal integer
+    (seq ?. (submatch-n 3 (+ (in num)))))))        ; 3 - decimal fraction
 
 (defun num3--matcher (lim)
   "Function used as a font-lock-keywoard handler used in `num3-mode'.