Add arrows to paired string delimiters

Unicode has lots of arrows of various shapes, sizes, and directions.
None of them were of consequence to the Bidirectional algorithm, so none
were specified as being mirrored pairs.  This commit uses the
generalizations already in place from previous commits to examine arrow
symbols and choose which are mirrored pairs.

As previously, it rejects arrows with contrary directionality, and ones
without horizontal directionality.

1 files changed, 162 insertions, 0 deletions

diff --git a/lib/feature.pm b/lib/feature.pm
index f96f99c16c..5dacd378cb 100644
--- a/lib/feature.pm
+++ b/lib/feature.pm
@@ -492,6 +492,32 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  ⁍  ⁌    U+204D, U+204C   BLACK RIGHT/LEFTWARDS BULLET
  ⁽  ⁾    U+207D, U+207E   SUPERSCRIPT LEFT/RIGHT PARENTHESIS
  ₍  ₎    U+208D, U+208E   SUBSCRIPT LEFT/RIGHT PARENTHESIS
+ →  ←    U+2192, U+2190   RIGHT/LEFTWARDS ARROW
+ ↛  ↚    U+219B, U+219A   RIGHT/LEFTWARDS ARROW WITH STROKE
+ ↝  ↜    U+219D, U+219C   RIGHT/LEFTWARDS WAVE ARROW
+ ↠  ↞    U+21A0, U+219E   RIGHT/LEFTWARDS TWO HEADED ARROW
+ ↣  ↢    U+21A3, U+21A2   RIGHT/LEFTWARDS ARROW WITH TAIL
+ ↦  ↤    U+21A6, U+21A4   RIGHT/LEFTWARDS ARROW FROM BAR
+ ↪  ↩    U+21AA, U+21A9   RIGHT/LEFTWARDS ARROW WITH HOOK
+ ↬  ↫    U+21AC, U+21AB   RIGHT/LEFTWARDS ARROW WITH LOOP
+ ↱  ↰    U+21B1, U+21B0   UPWARDS ARROW WITH TIP RIGHT/LEFTWARDS
+ ↳  ↲    U+21B3, U+21B2   DOWNWARDS ARROW WITH TIP RIGHT/LEFTWARDS
+ ⇀  ↼    U+21C0, U+21BC   RIGHT/LEFTWARDS HARPOON WITH BARB UPWARDS
+ ⇁  ↽    U+21C1, U+21BD   RIGHT/LEFTWARDS HARPOON WITH BARB DOWNWARDS
+ ⇉  ⇇    U+21C9, U+21C7   RIGHT/LEFTWARDS PAIRED ARROWS
+ ⇏  ⇍    U+21CF, U+21CD   RIGHT/LEFTWARDS DOUBLE ARROW WITH STROKE
+ ⇒  ⇐    U+21D2, U+21D0   RIGHT/LEFTWARDS DOUBLE ARROW
+ ⇛  ⇚    U+21DB, U+21DA   RIGHT/LEFTWARDS TRIPLE ARROW
+ ⇝  ⇜    U+21DD, U+21DC   RIGHT/LEFTWARDS SQUIGGLE ARROW
+ ⇢  ⇠    U+21E2, U+21E0   RIGHT/LEFTWARDS DASHED ARROW
+ ⇥  ⇤    U+21E5, U+21E4   RIGHT/LEFTWARDS ARROW TO BAR
+ ⇨  ⇦    U+21E8, U+21E6   RIGHT/LEFTWARDS WHITE ARROW
+ ⇴  ⬰    U+21F4, U+2B30   RIGHT/LEFT ARROW WITH SMALL CIRCLE
+ ⇶  ⬱    U+21F6, U+2B31   THREE RIGHT/LEFTWARDS ARROWS
+ ⇸  ⇷    U+21F8, U+21F7   RIGHT/LEFTWARDS ARROW WITH VERTICAL STROKE
+ ⇻  ⇺    U+21FB, U+21FA   RIGHT/LEFTWARDS ARROW WITH DOUBLE VERTICAL
+                          STROKE
+ ⇾  ⇽    U+21FE, U+21FD   RIGHT/LEFTWARDS OPEN-HEADED ARROW
  ∈  ∋    U+2208, U+220B   ELEMENT OF,  CONTAINS AS MEMBER
  ∉  ∌    U+2209, U+220C   NOT AN ELEMENT OF,  DOES NOT CONTAIN AS MEMBER
  ∊  ∍    U+220A, U+220D   SMALL ELEMENT OF,  SMALL CONTAINS AS MEMBER
@@ -536,6 +562,7 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  ⌊  ⌋    U+230A, U+230B   LEFT/RIGHT FLOOR
  ⌦  ⌫    U+2326, U+232B   ERASE TO THE RIGHT/LEFT
  〈 〉   U+2329, U+232A   LEFT/RIGHT-POINTING ANGLE BRACKET
+ ⍈  ⍇    U+2348, U+2347   APL FUNCTIONAL SYMBOL QUAD RIGHT/LEFTWARDS ARROW
  ⏩ ⏪   U+23E9, U+23EA   BLACK RIGHT/LEFT-POINTING DOUBLE TRIANGLE
  ⏭  ⏮    U+23ED, U+23EE   BLACK RIGHT/LEFT-POINTING DOUBLE TRIANGLE WITH
                           VERTICAL BAR
@@ -562,6 +589,60 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  ⟬  ⟭    U+27EC, U+27ED   MATHEMATICAL LEFT/RIGHT WHITE TORTOISE SHELL
                           BRACKET
  ⟮  ⟯    U+27EE, U+27EF   MATHEMATICAL LEFT/RIGHT FLATTENED PARENTHESIS
+ ⟴  ⬲    U+27F4, U+2B32   RIGHT/LEFT ARROW WITH CIRCLED PLUS
+ ⟶  ⟵    U+27F6, U+27F5   LONG RIGHT/LEFTWARDS ARROW
+ ⟹  ⟸    U+27F9, U+27F8   LONG RIGHT/LEFTWARDS DOUBLE ARROW
+ ⟼  ⟻    U+27FC, U+27FB   LONG RIGHT/LEFTWARDS ARROW FROM BAR
+ ⟾  ⟽    U+27FE, U+27FD   LONG RIGHT/LEFTWARDS DOUBLE ARROW FROM BAR
+ ⟿  ⬳    U+27FF, U+2B33   LONG RIGHT/LEFTWARDS SQUIGGLE ARROW
+ ⤀  ⬴    U+2900, U+2B34   RIGHT/LEFTWARDS TWO-HEADED ARROW WITH VERTICAL
+                          STROKE
+ ⤁  ⬵    U+2901, U+2B35   RIGHT/LEFTWARDS TWO-HEADED ARROW WITH DOUBLE
+                          VERTICAL STROKE
+ ⤃  ⤂    U+2903, U+2902   RIGHT/LEFTWARDS DOUBLE ARROW WITH VERTICAL
+                          STROKE
+ ⤅  ⬶    U+2905, U+2B36   RIGHT/LEFTWARDS TWO-HEADED ARROW FROM BAR
+ ⤇  ⤆    U+2907, U+2906   RIGHT/LEFTWARDS DOUBLE ARROW FROM BAR
+ ⤍  ⤌    U+290D, U+290C   RIGHT/LEFTWARDS DOUBLE DASH ARROW
+ ⤏  ⤎    U+290F, U+290E   RIGHT/LEFTWARDS TRIPLE DASH ARROW
+ ⤐  ⬷    U+2910, U+2B37   RIGHT/LEFTWARDS TWO-HEADED TRIPLE DASH ARROW
+ ⤑  ⬸    U+2911, U+2B38   RIGHT/LEFTWARDS ARROW WITH DOTTED STEM
+ ⤔  ⬹    U+2914, U+2B39   RIGHT/LEFTWARDS ARROW WITH TAIL WITH VERTICAL
+                          STROKE
+ ⤕  ⬺    U+2915, U+2B3A   RIGHT/LEFTWARDS ARROW WITH TAIL WITH DOUBLE
+                          VERTICAL STROKE
+ ⤖  ⬻    U+2916, U+2B3B   RIGHT/LEFTWARDS TWO-HEADED ARROW WITH TAIL
+ ⤗  ⬼    U+2917, U+2B3C   RIGHT/LEFTWARDS TWO-HEADED ARROW WITH TAIL WITH
+                          VERTICAL STROKE
+ ⤘  ⬽    U+2918, U+2B3D   RIGHT/LEFTWARDS TWO-HEADED ARROW WITH TAIL WITH
+                          DOUBLE VERTICAL STROKE
+ ⤚  ⤙    U+291A, U+2919   RIGHT/LEFTWARDS ARROW-TAIL
+ ⤜  ⤛    U+291C, U+291B   RIGHT/LEFTWARDS DOUBLE ARROW-TAIL
+ ⤞  ⤝    U+291E, U+291D   RIGHT/LEFTWARDS ARROW TO BLACK DIAMOND
+ ⤠  ⤟    U+2920, U+291F   RIGHT/LEFTWARDS ARROW FROM BAR TO BLACK DIAMOND
+ ⤳  ⬿    U+2933, U+2B3F   WAVE ARROW POINTING DIRECTLY RIGHT/LEFT
+ ⤷  ⤶    U+2937, U+2936   ARROW POINTING DOWNWARDS THEN CURVING RIGHT/
+                          LEFTWARDS
+ ⥅  ⥆    U+2945, U+2946   RIGHT/LEFTWARDS ARROW WITH PLUS BELOW
+ ⥇  ⬾    U+2947, U+2B3E   RIGHT/LEFTWARDS ARROW THROUGH X
+ ⥓  ⥒    U+2953, U+2952   RIGHT/LEFTWARDS HARPOON WITH BARB UP TO BAR
+ ⥗  ⥖    U+2957, U+2956   RIGHT/LEFTWARDS HARPOON WITH BARB DOWN TO BAR
+ ⥛  ⥚    U+295B, U+295A   RIGHT/LEFTWARDS HARPOON WITH BARB UP FROM BAR
+ ⥟  ⥞    U+295F, U+295E   RIGHT/LEFTWARDS HARPOON WITH BARB DOWN FROM BAR
+ ⥤  ⥢    U+2964, U+2962   RIGHT/LEFTWARDS HARPOON WITH BARB UP ABOVE
+                          RIGHT/LEFTWARDS HARPOON WITH BARB DOWN
+ ⥬  ⥪    U+296C, U+296A   RIGHT/LEFTWARDS HARPOON WITH BARB UP ABOVE LONG
+                          DASH
+ ⥭  ⥫    U+296D, U+296B   RIGHT/LEFTWARDS HARPOON WITH BARB DOWN BELOW
+                          LONG DASH
+ ⥱  ⭀    U+2971, U+2B40   EQUALS SIGN ABOVE RIGHT/LEFTWARDS ARROW
+ ⥲  ⭁    U+2972, U+2B41   TILDE OPERATOR ABOVE RIGHTWARDS ARROW,  REVERSE
+                          TILDE OPERATOR ABOVE LEFTWARDS ARROW
+ ⥴  ⭋    U+2974, U+2B4B   RIGHTWARDS ARROW ABOVE TILDE OPERATOR,
+                          LEFTWARDS ARROW ABOVE REVERSE TILDE OPERATOR
+ ⥵  ⭂    U+2975, U+2B42   RIGHTWARDS ARROW ABOVE ALMOST EQUAL TO,
+                          LEFTWARDS ARROW ABOVE REVERSE ALMOST EQUAL TO
+ ⥹  ⥻    U+2979, U+297B   SUBSET/SUPERSET ABOVE RIGHT/LEFTWARDS ARROW
  ⦃  ⦄    U+2983, U+2984   LEFT/RIGHT WHITE CURLY BRACKET
  ⦅  ⦆    U+2985, U+2986   LEFT/RIGHT WHITE PARENTHESIS
  ⦇  ⦈    U+2987, U+2988   Z NOTATION LEFT/RIGHT IMAGE BRACKET
@@ -576,6 +657,11 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  ⦕  ⦖    U+2995, U+2996   DOUBLE LEFT/RIGHT ARC GREATER-THAN/LESS-THAN
                           BRACKET
  ⦗  ⦘    U+2997, U+2998   LEFT/RIGHT BLACK TORTOISE SHELL BRACKET
+ ⦨  ⦩    U+29A8, U+29A9   MEASURED ANGLE WITH OPEN ARM ENDING IN ARROW
+                          POINTING UP AND RIGHT/LEFT
+ ⦪  ⦫    U+29AA, U+29AB   MEASURED ANGLE WITH OPEN ARM ENDING IN ARROW
+                          POINTING DOWN AND RIGHT/LEFT
+ ⦳  ⦴    U+29B3, U+29B4   EMPTY SET WITH RIGHT/LEFT ARROW ABOVE
  ⧀  ⧁    U+29C0, U+29C1   CIRCLED LESS-THAN/GREATER-THAN
  ⧘  ⧙    U+29D8, U+29D9   LEFT/RIGHT WIGGLY FENCE
  ⧚  ⧛    U+29DA, U+29DB   LEFT/RIGHT DOUBLE WIGGLY FENCE
@@ -631,6 +717,34 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  ⫷  ⫸    U+2AF7, U+2AF8   TRIPLE NESTED LESS-THAN/GREATER-THAN
  ⫹  ⫺    U+2AF9, U+2AFA   DOUBLE-LINE SLANTED LESS-THAN/GREATER-THAN OR
                           EQUAL TO
+ ⭆  ⭅    U+2B46, U+2B45   RIGHT/LEFTWARDS QUADRUPLE ARROW
+ ⭇  ⭉    U+2B47, U+2B49   REVERSE TILDE OPERATOR ABOVE RIGHTWARDS ARROW,
+                          TILDE OPERATOR ABOVE LEFTWARDS ARROW
+ ⭈  ⭊    U+2B48, U+2B4A   RIGHTWARDS ARROW ABOVE REVERSE ALMOST EQUAL
+                          TO,  LEFTWARDS ARROW ABOVE ALMOST EQUAL TO
+ ⭌  ⥳    U+2B4C, U+2973   RIGHTWARDS ARROW ABOVE REVERSE TILDE OPERATOR,
+                          LEFTWARDS ARROW ABOVE TILDE OPERATOR
+ ⭢  ⭠    U+2B62, U+2B60   RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW
+ ⭬  ⭪    U+2B6C, U+2B6A   RIGHT/LEFTWARDS TRIANGLE-HEADED DASHED ARROW
+ ⭲  ⭰    U+2B72, U+2B70   RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW TO BAR
+ ⭼  ⭺    U+2B7C, U+2B7A   RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW WITH
+                          DOUBLE VERTICAL STROKE
+ ⮆  ⮄    U+2B86, U+2B84   RIGHT/LEFTWARDS TRIANGLE-HEADED PAIRED ARROWS
+ ⮊  ⮈    U+2B8A, U+2B88   RIGHT/LEFTWARDS BLACK CIRCLED WHITE ARROW
+ ⮕  ⬅    U+2B95, U+2B05   RIGHT/LEFTWARDS BLACK ARROW
+ ⮚  ⮘    U+2B9A, U+2B98   THREE-D TOP-LIGHTED RIGHT/LEFTWARDS EQUILATERAL
+                          ARROWHEAD
+ ⮞  ⮜    U+2B9E, U+2B9C   BLACK RIGHT/LEFTWARDS EQUILATERAL ARROWHEAD
+ ⮡  ⮠    U+2BA1, U+2BA0   DOWNWARDS TRIANGLE-HEADED ARROW WITH LONG TIP
+                          RIGHT/LEFTWARDS
+ ⮣  ⮢    U+2BA3, U+2BA2   UPWARDS TRIANGLE-HEADED ARROW WITH LONG TIP
+                          RIGHT/LEFTWARDS
+ ⮩  ⮨    U+2BA9, U+2BA8   BLACK CURVED DOWNWARDS AND RIGHT/LEFTWARDS ARROW
+ ⮫  ⮪    U+2BAB, U+2BAA   BLACK CURVED UPWARDS AND RIGHT/LEFTWARDS ARROW
+ ⮱  ⮰    U+2BB1, U+2BB0   RIBBON ARROW DOWN RIGHT/LEFT
+ ⮳  ⮲    U+2BB3, U+2BB2   RIBBON ARROW UP RIGHT/LEFT
+ ⯮  ⯬    U+2BEE, U+2BEC   RIGHT/LEFTWARDS TWO-HEADED ARROW WITH TRIANGLE
+                          ARROWHEADS
  ⸂  ⸃    U+2E02, U+2E03   LEFT/RIGHT SUBSTITUTION BRACKET
  ⸃  ⸂    U+2E03, U+2E02   RIGHT/LEFT SUBSTITUTION BRACKET
  ⸄  ⸅    U+2E04, U+2E05   LEFT/RIGHT DOTTED SUBSTITUTION BRACKET
@@ -678,6 +792,7 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  ｛ ｝   U+FF5B, U+FF5D   FULLWIDTH LEFT/RIGHT CURLY BRACKET
  ｟ ｠   U+FF5F, U+FF60   FULLWIDTH LEFT/RIGHT WHITE PARENTHESIS
  ｢  ｣    U+FF62, U+FF63   HALFWIDTH LEFT/RIGHT CORNER BRACKET
+ ￫  ￩    U+FFEB, U+FFE9   HALFWIDTH RIGHT/LEFTWARDS ARROW
  𝄃  𝄂    U+1D103, U+1D102 MUSICAL SYMBOL REVERSE FINAL BARLINE,  MUSICAL
                           SYMBOL FINAL BARLINE
  𝄆  𝄇    U+1D106, U+1D107 MUSICAL SYMBOL LEFT/RIGHT REPEAT SIGN
@@ -692,6 +807,53 @@ The complete list of accepted paired delimiters as of Unicode 14.0 is:
  🖛  🖚    U+1F59B, U+1F59A SIDEWAYS BLACK RIGHT/LEFT POINTING INDEX
  🖝  🖜    U+1F59D, U+1F59C BLACK RIGHT/LEFT POINTING BACKHAND INDEX
  🗦  🗧    U+1F5E6, U+1F5E7 THREE RAYS LEFT/RIGHT
+ 🠂  🠀    U+1F802, U+1F800 RIGHT/LEFTWARDS ARROW WITH SMALL TRIANGLE
+                          ARROWHEAD
+ 🠆  🠄    U+1F806, U+1F804 RIGHT/LEFTWARDS ARROW WITH MEDIUM TRIANGLE
+                          ARROWHEAD
+ 🠊  🠈    U+1F80A, U+1F808 RIGHT/LEFTWARDS ARROW WITH LARGE TRIANGLE
+                          ARROWHEAD
+ 🠒  🠐    U+1F812, U+1F810 RIGHT/LEFTWARDS ARROW WITH SMALL EQUILATERAL
+                          ARROWHEAD
+ 🠖  🠔    U+1F816, U+1F814 RIGHT/LEFTWARDS ARROW WITH EQUILATERAL ARROWHEAD
+ 🠚  🠘    U+1F81A, U+1F818 HEAVY RIGHT/LEFTWARDS ARROW WITH EQUILATERAL
+                          ARROWHEAD
+ 🠞  🠜    U+1F81E, U+1F81C HEAVY RIGHT/LEFTWARDS ARROW WITH LARGE
+                          EQUILATERAL ARROWHEAD
+ 🠢  🠠    U+1F822, U+1F820 RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW WITH
+                          NARROW SHAFT
+ 🠦  🠤    U+1F826, U+1F824 RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW WITH
+                          MEDIUM SHAFT
+ 🠪  🠨    U+1F82A, U+1F828 RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW WITH BOLD
+                          SHAFT
+ 🠮  🠬    U+1F82E, U+1F82C RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW WITH
+                          HEAVY SHAFT
+ 🠲  🠰    U+1F832, U+1F830 RIGHT/LEFTWARDS TRIANGLE-HEADED ARROW WITH VERY
+                          HEAVY SHAFT
+ 🠶  🠴    U+1F836, U+1F834 RIGHT/LEFTWARDS FINGER-POST ARROW
+ 🠺  🠸    U+1F83A, U+1F838 RIGHT/LEFTWARDS SQUARED ARROW
+ 🠾  🠼    U+1F83E, U+1F83C RIGHT/LEFTWARDS COMPRESSED ARROW
+ 🡂  🡀    U+1F842, U+1F840 RIGHT/LEFTWARDS HEAVY COMPRESSED ARROW
+ 🡆  🡄    U+1F846, U+1F844 RIGHT/LEFTWARDS HEAVY ARROW
+ 🡒  🡐    U+1F852, U+1F850 RIGHT/LEFTWARDS SANS-SERIF ARROW
+ 🡢  🡠    U+1F862, U+1F860 WIDE-HEADED RIGHT/LEFTWARDS LIGHT BARB ARROW
+ 🡪  🡨    U+1F86A, U+1F868 WIDE-HEADED RIGHT/LEFTWARDS BARB ARROW
+ 🡲  🡰    U+1F872, U+1F870 WIDE-HEADED RIGHT/LEFTWARDS MEDIUM BARB ARROW
+ 🡺  🡸    U+1F87A, U+1F878 WIDE-HEADED RIGHT/LEFTWARDS HEAVY BARB ARROW
+ 🢂  🢀    U+1F882, U+1F880 WIDE-HEADED RIGHT/LEFTWARDS VERY HEAVY BARB
+                          ARROW
+ 🢒  🢐    U+1F892, U+1F890 RIGHT/LEFTWARDS TRIANGLE ARROWHEAD
+ 🢖  🢔    U+1F896, U+1F894 RIGHT/LEFTWARDS WHITE ARROW WITHIN TRIANGLE
+                          ARROWHEAD
+ 🢚  🢘    U+1F89A, U+1F898 RIGHT/LEFTWARDS ARROW WITH NOTCHED TAIL
+ 🢡  🢠    U+1F8A1, U+1F8A0 RIGHTWARDS BOTTOM SHADED WHITE ARROW,
+                          LEFTWARDS BOTTOM-SHADED WHITE ARROW
+ 🢣  🢢    U+1F8A3, U+1F8A2 RIGHT/LEFTWARDS TOP SHADED WHITE ARROW
+ 🢥  🢦    U+1F8A5, U+1F8A6 RIGHT/LEFTWARDS RIGHT-SHADED WHITE ARROW
+ 🢧  🢤    U+1F8A7, U+1F8A4 RIGHT/LEFTWARDS LEFT-SHADED WHITE ARROW
+ 🢩  🢨    U+1F8A9, U+1F8A8 RIGHT/LEFTWARDS BACK-TILTED SHADOWED WHITE ARROW
+ 🢫  🢪    U+1F8AB, U+1F8AA RIGHT/LEFTWARDS FRONT-TILTED SHADOWED WHITE
+                          ARROW
 
 =head1 FEATURE BUNDLES