buffer: fix some search bugs & refactor regex stuff

cursorBytes uses twidth now.
cursorNextMatch matches the byte *after* the cursor (somewhat more
consistently than before).
match() no longer counts capture groups. LRE_FLAG_GLOBAL now goes
through the entire string.

1 files changed, 24 insertions, 18 deletions

diff --git a/src/utils/twtstr.nim b/src/utils/twtstr.nim
index 96d4bf2f..d89a70ac 100644
--- a/src/utils/twtstr.nim
+++ b/src/utils/twtstr.nim
@@ -162,6 +162,12 @@ func decValue*(c: char): int =
 func isAscii*(r: Rune): bool =
   return int32(r) < 128
 
+func isAscii*(s: string): bool =
+  for c in s:
+    if c > char(0x80):
+      return false
+  return true
+
 const HexChars = "0123456789ABCDEF"
 func toHex*(c: char): string =
   result = newString(2)
@@ -993,47 +999,47 @@ func width*(r: Rune): int =
     return int(width_table[int(r)])
 {.pop.}
 
-func width*(s: string, len: int): int =
-  var i = 0
+# Width, but also works with tabs.
+# Needs the column width of the text so far.
+func twidth*(r: Rune, w: int): int =
+  if r != Rune('\t'):
+    return r.width()
+  return ((w div 8) + 1) * 8 - w
+
+func width*(s: string): int =
+  for r in s.runes():
+    result += r.twidth(result)
+
+func width*(s: string, start, len: int): int =
+  var i = start
   var m = len
   if m > s.len: m = s.len
   while i < m:
     var r: Rune
     fastRuneAt(s, i, r)
-    result += width(r)
+    result += r.twidth(result)
 
 func width*(s: seq[Rune]): int =
   for r in s:
-    result += width(r)
+    result += r.twidth(result)
 
 func width*(s: seq[Rune], min, max: int): int =
   var i = min
   var mi = min(max, s.len)
   while i < mi:
-    result += width(s[i])
+    result += s[i].twidth(result)
     inc i
 
 func width*(s: seq[Rune], min: int): int =
   var i = min
   while i < s.len:
-    result += width(s[i])
+    result += s[i].twidth(result)
     inc i
 
-# Width, but also works with tabs.
-# Needs the column width of the text so far.
-func twidth*(r: Rune, w: int): int =
-  if r != Rune('\t'):
-    return r.width()
-  return ((w div 8) + 1) * 8 - w
-
-func width*(s: string): int =
-  for r in s.runes():
-    result += twidth(r, result)
-
 func twidth*(s: string, w: int): int =
   result = w
   for r in s.runes():
-    result += twidth(r, result)
+    result += r.twidth(result)
 
 func breaksWord*(r: Rune): bool =
   return not (r.isDigitAscii() or r.width() == 0 or r.isAlpha())