Make scanner use char directly instead of converting back and forth between char and int

Author: chenglou

src/res_character_codes.ml

@@ -1,137 +1,18 @@
-let eof = -1
+let eof = Char.unsafe_chr (-1)
 
-let space = 0x0020
-let newline = 0x0A (* \n *) [@@live]
-let lineFeed = 0x0A (* \n *)
-let carriageReturn = 0x0D  (* \r *)
-let lineSeparator = 0x2028
-let paragraphSeparator = 0x2029
+let lineSeparator = Char.unsafe_chr 0x2028
+let paragraphSeparator = Char.unsafe_chr 0x2029
 
-let tab = 0x09
+let isUpperCase ch = 'A' <= ch && ch <= 'Z' [@@inline]
+let isLowerCase ch = 'a' <= ch && ch <= 'z' [@@inline]
 
-let bang = 0x21
-let dot = 0x2E
-let colon = 0x3A
-let comma = 0x2C
-let backtick = 0x60
-(* let question = 0x3F *)
-let semicolon = 0x3B
-let underscore = 0x5F
-let singleQuote = 0x27
-let doubleQuote = 0x22
-let equal = 0x3D
-let bar = 0x7C
-let tilde = 0x7E
-let question = 0x3F
-let ampersand = 0x26
-let at = 0x40
-let dollar = 0x24
-let percent = 0x25
+let isDigit ch = '0' <= ch && ch <= '9' [@@inline]
 
-let lparen = 0x28
-let rparen = 0x29
-let lbracket = 0x5B
-let rbracket = 0x5D
-let lbrace = 0x7B
-let rbrace = 0x7D
+let isLetter ch = isUpperCase ch || isLowerCase ch
 
-let forwardslash = 0x2F (* / *)
-let backslash = 0x5C (* \ *)
-
-let greaterThan = 0x3E
-let hash = 0x23
-let lessThan = 0x3C
-
-let minus = 0x2D
-let plus = 0x2B
-let asterisk = 0x2A
-
-let _0 = 0x30
-let _1 = 0x31 [@@live]
-let _2 = 0x32 [@@live]
-let _3 = 0x33 [@@live]
-let _4 = 0x34 [@@live]
-let _5 = 0x35 [@@live]
-let _6 = 0x36 [@@live]
-let _7 = 0x37 [@@live]
-let _8 = 0x38 [@@live]
-let _9 = 0x39
-
-module Lower = struct
-  let a = 0x61
-  let b = 0x62
-  let c = 0x63 [@@live]
-  let d = 0x64 [@@live]
-  let e = 0x65
-  let f = 0x66
-  let g = 0x67
-  let h = 0x68 [@@live]
-  let i = 0x69 [@@live]
-  let j = 0x6A [@@live]
-  let k = 0x6B [@@live]
-  let l = 0x6C [@@live]
-  let m = 0x6D [@@live]
-  let n = 0x6E
-  let o = 0x6F
-  let p = 0x70
-  let q = 0x71 [@@live]
-  let r = 0x72
-  let s = 0x73 [@@live]
-  let t = 0x74
-  let u = 0x75 [@@live]
-  let v = 0x76 [@@live]
-  let w = 0x77 [@@live]
-  let x = 0x78
-  let y = 0x79 [@@live]
-  let z = 0x7A
-end
-
-module Upper = struct
-  let a = 0x41
-  (* let b = 0x42 *)
-  let c = 0x43 [@@live]
-  let d = 0x44 [@@live]
-  let e = 0x45 [@@live]
-  let f = 0x46 [@@live]
-  let g = 0x47
-  let h = 0x48 [@@live]
-  let i = 0x49 [@@live]
-  let j = 0x4A [@@live]
-  let k = 0x4B [@@live]
-  let l = 0x4C [@@live]
-  let m = 0x4D [@@live]
-  let b = 0x4E [@@live]
-  let o = 0x4F [@@live]
-  let p = 0x50 [@@live]
-  let q = 0x51 [@@live]
-  let r = 0x52 [@@live]
-  let s = 0x53 [@@live]
-  let t = 0x54 [@@live]
-  let u = 0x55 [@@live]
-  let v = 0x56 [@@live]
-  let w = 0x57 [@@live]
-  let x = 0x58 [@@live]
-  let y = 0x59 [@@live]
-  let z = 0x5a
-end
-
-(* returns lower-case ch, ch should be ascii *)
-let lower ch =
-  (* if ch >= Lower.a && ch <= Lower.z then ch else ch + 32 *)
-  32 lor ch
-
-let isLetter ch =
-  Lower.a <= ch && ch <= Lower.z ||
-  Upper.a <= ch && ch <= Upper.z
-
-let isUpperCase ch =
-  Upper.a <= ch && ch <= Upper.z
-
-let isDigit ch = _0 <= ch && ch <= _9
-
-let isHex ch =
-  (_0 <= ch && ch <= _9) ||
-  (Lower.a <= (lower ch) && (lower ch) <= Lower.f)
+let isHex = function
+  | '0'..'9' | 'a'..'f' | 'A'..'F' -> true
+  | _ -> false
 
   (*
     // ES5 7.3:
@@ -146,15 +27,16 @@ let isHex ch =
     // breaking characters are treated as white space but not as line terminators.
 *)
 let isLineBreak ch =
-     ch == lineFeed
-  || ch == carriageReturn
+     ch == '\n'
+  || ch == '\r'
   || ch == lineSeparator
   || ch == paragraphSeparator
 
 let digitValue ch =
-  if _0 <= ch && ch <= _9 then
-    ch - 48
-  else if Lower.a <= (lower ch) && (lower ch) <= Lower.f then
-    (lower ch) - Lower.a + 10
-  else
-    16 (* larger than any legal value *)
+  match ch with
+  | '0'..'9' -> (Char.code ch) - 48
+  | 'a'..'f' ->
+    (Char.code ch) - (Char.code 'a') + 10
+  | 'A'..'F' ->
+    (Char.code ch) + 32 - (Char.code 'a') + 10
+  | _ -> 16 (* larger than any legal value *)

src/res_core.ml

@@ -861,7 +861,7 @@ let parseTemplateStringLiteral s =
           | '`' as c ->
             Buffer.add_char b c;
             loop (i + 2)
-          | c when Res_character_codes.isLineBreak (Char.code c) ->
+          | c when Res_character_codes.isLineBreak c ->
             loop (i + 2)
           | c ->
             Buffer.add_char b '\\';

src/res_diagnostics.ml

@@ -10,7 +10,7 @@ type category =
   | UnclosedString
   | UnclosedTemplate
   | UnclosedComment
-  | UnknownUchar of int
+  | UnknownUchar of Char.t
 
 type t = {
   startPos: Lexing.position;
@@ -65,7 +65,7 @@ let explain t =
     "This comment seems to be missing a closing `*/`"
   | UnknownUchar uchar ->
     begin match uchar with
-    | 94 (* ^ *) ->
+    | '^' ->
       "Hmm, not sure what I should do here with this character.\nIf you're trying to deref an expression, use `foo.contents` instead."
     | _ ->
       "Hmm, I have no idea what this character means…"

src/res_diagnostics.mli

@@ -17,7 +17,7 @@ val lident: Token.t -> category
 val unclosedString: category
 val unclosedTemplate: category
 val unclosedComment: category
-val unknownUchar: int -> category
+val unknownUchar: Char.t -> category
 val message: string -> category
 
 val make: