minor improvements

src/regex/common.nim

@@ -19,13 +19,13 @@ const
   # Nim and not the actual `\n`
   lineBreakRune* = Rune(10)
 
-proc toRune*(s: string): Rune =
-  result = s.runeAt(0)
+func toRune*(c: char): Rune =
+  result = Rune(c.ord)
 
-proc `<=`*(x, y: Rune): bool =
+func `<=`*(x, y: Rune): bool =
   x.int <= y.int
 
-proc cmp*(x, y: Rune): int =
+func cmp*(x, y: Rune): int =
   x.int - y.int
 
 func bwRuneAt*(s: string, n: int): Rune =

src/regex/exptransformation.nim

@@ -256,7 +256,7 @@ func expandOneRepRange(subExpr: seq[Node], n: Node): seq[Node] =
       result.add(subExpr)
     result.add(Node(
       kind: reZeroOrMore,
-      cp: "*".toRune,
+      cp: '*'.toRune,
       isGreedy: n.isGreedy))
   elif n.min == n.max:  # a{n} -> aaa
     result = newSeqOfCap[Node](subExpr.len * n.max)
@@ -270,12 +270,12 @@ func expandOneRepRange(subExpr: seq[Node], n: Node): seq[Node] =
     for _ in n.min ..< n.max - 1:
       result.add(Node(
         kind: reZeroOrOne,
-        cp: "?".toRune,
+        cp: '?'.toRune,
         isGreedy: n.isGreedy))
       result.add(subExpr)
     result.add(Node(
       kind: reZeroOrOne,
-      cp: "?".toRune,
+      cp: '?'.toRune,
       isGreedy: n.isGreedy))
 
 func expandRepRange(exp: Exp): Exp =