[use] Reintroduce the HVM class for U+0DCA

src/gen-use-table.py

@@ -221,7 +221,10 @@ def is_CONS_SUB(U, UISC, UDI, UGC, AJT):
 def is_CONS_WITH_STACKER(U, UISC, UDI, UGC, AJT):
 	return UISC == Consonant_With_Stacker
 def is_HALANT(U, UISC, UDI, UGC, AJT):
-	return UISC == Virama
+	return UISC == Virama and not is_HALANT_OR_VOWEL_MODIFIER(U, UISC, UDI, UGC, AJT)
+def is_HALANT_OR_VOWEL_MODIFIER(U, UISC, UDI, UGC, AJT):
+	# Split off of HALANT
+	return U == 0x0DCA
 def is_HALANT_NUM(U, UISC, UDI, UGC, AJT):
 	return UISC == Number_Joiner
 def is_HIEROGLYPH(U, UISC, UDI, UGC, AJT):
@@ -280,6 +283,7 @@ use_mapping = {
 	'SUB':	is_CONS_SUB,
 	'CS':	is_CONS_WITH_STACKER,
 	'H':	is_HALANT,
+	'HVM':	is_HALANT_OR_VOWEL_MODIFIER,
 	'HN':	is_HALANT_NUM,
 	'IS':	is_INVISIBLE_STACKER,
 	'G':	is_HIEROGLYPH,
@@ -329,6 +333,7 @@ use_positions = {
 		'Blw': [Bottom],
 	},
 	'H': None,
+	'HVM': None,
 	'IS': None,
 	'B': None,
 	'FM': {

src/hb-ot-shaper-use-machine.rl

@@ -82,6 +82,7 @@ export G	= 49; # HIEROGLYPH
 export J	= 50; # HIEROGLYPH_JOINER
 export SB	= 51; # HIEROGLYPH_SEGMENT_BEGIN
 export SE	= 52; # HIEROGLYPH_SEGMENT_END
+export HVM	= 53; # HALANT_OR_VOWEL_MODIFIER
 
 export FAbv	= 24; # CONS_FINAL_ABOVE
 export FBlw	= 25; # CONS_FINAL_BELOW
@@ -107,12 +108,12 @@ export FMBlw	= 46; # CONS_FINAL_MOD	UIPC = Bottom
 export FMPst	= 47; # CONS_FINAL_MOD	UIPC = Not_Applicable
 
 
-h = H | IS | Sk;
+h = H | HVM | IS | Sk;
 
 consonant_modifiers = CMAbv* CMBlw* ((h B | SUB) CMAbv? CMBlw*)*;
 medial_consonants = MPre? MAbv? MBlw? MPst?;
 dependent_vowels = VPre* VAbv* VBlw* VPst* | H;
-vowel_modifiers = VMPre* VMAbv* VMBlw* VMPst*;
+vowel_modifiers = HVM? VMPre* VMAbv* VMBlw* VMPst*;
 final_consonants = FAbv* FBlw* FPst*;
 final_modifiers = FMAbv* FMBlw* | FMPst?;
 

src/hb-ot-shaper-use-table.hh

@@ -53,6 +53,7 @@
 #define GB	USE(GB)	/* BASE_OTHER */
 #define H	USE(H)	/* HALANT */
 #define HN	USE(HN)	/* HALANT_NUM */
+#define HVM	USE(HVM)	/* HALANT_OR_VOWEL_MODIFIER */
 #define IS	USE(IS)	/* INVISIBLE_STACKER */
 #define J	USE(J)	/* HIEROGLYPH_JOINER */
 #define N	USE(N)	/* BASE_NUM */
@@ -246,7 +247,7 @@ static const uint8_t use_table[] = {
   /* 0D90 */     B,     B,     B,     B,     B,     B,     B,    WJ,    WJ,    WJ,     B,     B,     B,     B,     B,     B,
   /* 0DA0 */     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,
   /* 0DB0 */     B,     B,    WJ,     B,     B,     B,     B,     B,     B,     B,     B,     B,    WJ,     B,    WJ,    WJ,
-  /* 0DC0 */     B,     B,     B,     B,     B,     B,     B,    WJ,    WJ,    WJ,     H,    WJ,    WJ,    WJ,    WJ,  VPst,
+  /* 0DC0 */     B,     B,     B,     B,     B,     B,     B,    WJ,    WJ,    WJ,   HVM,    WJ,    WJ,    WJ,    WJ,  VPst,
   /* 0DD0 */  VPst,  VPst,  VAbv,  VAbv,  VBlw,    WJ,  VBlw,    WJ,  VPst,  VPre,  VPre,  VPre,  VPre,  VPre,  VPre,  VPst,
   /* 0DE0 */    WJ,    WJ,    WJ,    WJ,    WJ,    WJ,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,
   /* 0DF0 */    WJ,    WJ,  VPst,  VPst,     O,    WJ,    WJ,    WJ,
@@ -1531,6 +1532,7 @@ hb_use_get_category (hb_glyph_info_t info)
 #undef GB
 #undef H
 #undef HN
+#undef HVM
 #undef IS
 #undef J
 #undef N

src/hb-ot-shaper-use.cc

@@ -351,7 +351,7 @@ record_pref_use (const hb_ot_shape_plan_t *plan HB_UNUSED,
 static inline bool
 is_halant_use (const hb_glyph_info_t &info)
 {
-  return (info.use_category() == USE(H) || info.use_category() == USE(IS)) &&
+  return (info.use_category() == USE(H) || info.use_category() == USE(HVM) || info.use_category() == USE(IS)) &&
 	 !_hb_glyph_info_ligated (&info);
 }