numbers with bases

src/Quox/Lexer.idr

@@ -3,6 +3,7 @@ module Quox.Lexer
 import Quox.Error
 
 import Data.String
+import Data.String.Extra
 import public Text.Lexer
 import public Text.Lexer.Tokenizer
 import Generics.Derive
@@ -59,40 +60,55 @@ wild = exact "_" <+> reject nameCont
 %hide Text.Lexer.symbol
 symbol = exact "'" <+> name
 
+number : Lexer -> Lexer
+number char = char <+> many (opt (is '_') <+> char) <+> reject nameCont
+
+octal       = approx "0o" <+> number octDigit
+decimal     = number digit
+hexadecimal = approx "0x" <+> number hexDigit
 
-decimal : Lexer
-decimal =
-  digit <+> opt (many (digit <|> is '_') <+> digit)
 
 natToNumber : Nat -> Number
 natToNumber 0 = Zero
 natToNumber 1 = One
 natToNumber k = Other k
 
-toDigit : Char -> Nat
-toDigit c = cast $ ord c - ord '0'
 
-makeDec' : Nat -> String -> Maybe Nat
-makeDec' acc x with (asList x)
-  makeDec' acc ""                | []         = pure acc
-  makeDec' acc (strCons '_' str) | '_' :: lst = makeDec' acc str | lst
-  makeDec' acc (strCons d   str) | d   :: lst =
-    if d >= '0' && d <= '9' then
-      makeDec' (acc * 10 + toDigit d) str | lst
-    else
-      Nothing
+toHexit : Char -> Nat
+toHexit c = cast $
+  if '0' <= c && c <= '9' then
+    ord c - ord '0'
+  else if 'a' <= c && c <= 'f' then
+    ord c - ord 'a' + 10
+  else if 'A' <= c && c <= 'F' then
+    ord c - ord 'A' + 10
+  else 0
+
+parameters (base : Nat) (single : Char -> Nat)
+  makeNat : Nat -> List Char -> Nat
+  makeNat acc []           = acc
+  makeNat acc ('_' :: lst) = makeNat acc lst
+  makeNat acc (d   :: lst) = makeNat (acc * base + single d) lst
+
+makeOct = makeNat  8 toHexit 0 . unpack
+makeDec = makeNat 10 toHexit 0 . unpack
+makeHex = makeNat 16 toHexit 0 . unpack
 
-makeDec = fromMaybe 0 . makeDec' 0
 
 skip : Lexer -> Tokenizer (Maybe a)
 skip lex = match lex $ const Nothing
 
 simple : List String -> a -> Tokenizer (Maybe a)
-simple str x = match (choice $ map exact str) $ const $ Just x
+simple str = match (choice $ map exact str) . const . Just
 
 choice : (xs : List (Tokenizer a)) -> {auto 0 _ : So (isCons xs)} -> Tokenizer a
 choice (t :: ts) = foldl (\a, b => a <|> b) t ts
 
+match : Lexer -> (String -> a) -> Tokenizer (Maybe a)
+match lex f = Tokenizer.match lex (Just . f)
+%hide Tokenizer.match
+
+
 tokens : Tokenizer (Maybe Token)
 tokens = choice [
   skip $ lineComment $ exact "--",
@@ -104,21 +120,23 @@ tokens = choice [
   simple ["{"] $ P LBrace,  simple ["}"] $ P RBrace,
   simple [","] $ P Comma,
   simple ["::", "∷"] $ P DblColon,
-  simple [":"] $ P Colon,
+  simple [":"] $ P Colon, -- needs to be after "::"
 
   simple ["->", "→"] $ P Arrow,
   simple ["=>", "⇒"] $ P DblArrow,
   simple ["**", "×"] $ P Times,
   simple ["<<", "⊲"] $ P Triangle,
-  match wild $ const $ Just $ P Wild,
+  match wild $ const $ P Wild,
 
-  match name   $ Just . Name,
-  match symbol $ Just . Symbol . assert_total strTail,
+  match name   $ Name,
+  match symbol $ Symbol . assert_total strTail,
 
-  -- [todo] other bases?
-  match (some $ digit <|> exact "_") $ Just . N . natToNumber . makeDec
+  match decimal     $ N . natToNumber . makeDec,
+  match hexadecimal $ N . natToNumber . makeHex . drop 2,
+  match octal       $ N . natToNumber . makeOct . drop 2
 ]
 
+
 export
 lex : MonadThrow Error m => String -> m (List (WithBounds Token))
 lex str =

tests/src/Tests/Lexer.idr

@@ -105,7 +105,8 @@ tests = "lexer" :- [
     acceptsWith' "'a"       [Symbol "a"],
     acceptsWith' "'ab"      [Symbol "ab"],
     acceptsWith' "'_b"      [Symbol "_b"],
-    rejects'     "'"
+    rejects'     "'",
+    rejects'     "1abc"
   ],
 
   "numbers" :- [
@@ -114,7 +115,19 @@ tests = "lexer" :- [
     acceptsWith' "2"      [N $ Other 2],
     acceptsWith' "69"     [N $ Other 69],
     acceptsWith' "1_000"  [N $ Other 1000],
-    todo "octal",
-    todo "hex"
+    acceptsWith' "0o0"    [N Zero],
+    acceptsWith' "0o105"  [N $ Other 69],
+    acceptsWith' "0O0"    [N Zero],
+    acceptsWith' "0O105"  [N $ Other 69],
+    acceptsWith' "0x0"    [N Zero],
+    acceptsWith' "0x45"   [N $ Other 69],
+    acceptsWith' "0xabc"  [N $ Other 2748],
+    acceptsWith' "0xABC"  [N $ Other 2748],
+    acceptsWith' "0xA_BC" [N $ Other 2748],
+    acceptsWith' "0X0"    [N Zero],
+    acceptsWith' "0X45"   [N $ Other 69],
+    acceptsWith' "0XABC"  [N $ Other 2748],
+    rejects'     "1_",
+    rejects'     "1__000"
   ]
 ]