simplify lexical grammar

this is a core language after all
This commit is contained in:
rhiannon morris 2022-05-07 21:26:16 +02:00
parent 1c8b2b205b
commit 809a0fc859
2 changed files with 31 additions and 75 deletions

View file

@ -27,17 +27,12 @@ nameCont = pred $ \c => isAlphaNum c || c == '_' || c == '\''
name = nameStart <+> many nameCont <+> reject nameCont
wild = exact "_" <+> reject nameCont
wild = is '_' <+> reject nameCont
%hide Text.Lexer.symbol
symbol = exact "'" <+> name
symbol = is '\'' <+> 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 = some digit <+> reject nameCont
natToNumber : Nat -> Number
@ -46,32 +41,11 @@ natToNumber 1 = One
natToNumber k = Other k
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
skip : Lexer -> Tokenizer (Maybe a)
skip lex = match lex $ const Nothing
simple : List String -> a -> Tokenizer (Maybe a)
simple strs = match (choice $ map exact strs) . const . Just
simple : Char -> a -> Tokenizer (Maybe a)
simple ch = match (is ch) . const . Just
keyword : String -> Keyword -> Tokenizer (Maybe Token)
keyword str = match (exact str <+> reject nameCont) . const . Just . K
@ -90,31 +64,31 @@ tokens = choice [
skip $ blockComment (exact "{-") (exact "-}"),
skip spaces,
simple ["("] $ P LParen, simple [")"] $ P RParen,
simple ["["] $ P LSquare, simple ["]"] $ P RSquare,
simple ["{"] $ P LBrace, simple ["}"] $ P RBrace,
simple [","] $ P Comma,
simple ["::", ""] $ P DblColon,
simple [":"] $ P Colon, -- needs to be after "::"
simple ["."] $ P Dot,
simple '(' $ P LParen, simple ')' $ P RParen,
simple '[' $ P LSquare, simple ']' $ P RSquare,
simple '{' $ P LBrace, simple '}' $ P RBrace,
simple ',' $ P Comma,
simple '' $ P DblColon,
simple ':' $ P Colon, -- needs to be after '::'
simple '.' $ P Dot,
simple ["->", ""] $ P Arrow,
simple ["=>", ""] $ P DblArrow,
simple ["**", "×"] $ P Times,
simple ["<<", ""] $ P Triangle,
simple '' $ P Arrow,
simple '' $ P DblArrow,
simple '×' $ P Times,
simple '' $ P Triangle,
match wild $ const $ P Wild,
keyword "fun" Fun, keyword "λ" Fun,
keyword "λ" Lam,
keyword "let" Let, keyword "in" In,
keyword "case" Case, keyword "of" Of,
keyword "ω" Omega, simple ["#"] $ K Omega,
keyword "ω" Omega,
keyword "Π" Pi, keyword "Σ" Sigma, keyword "W" W,
simple '' $ K TYPE,
match name $ Name,
match symbol $ Symbol . assert_total strTail,
match decimal $ N . natToNumber . makeDec,
match hexadecimal $ N . natToNumber . makeHex . drop 2,
match octal $ N . natToNumber . makeOct . drop 2
match decimal $ N . natToNumber . cast
]

View file

@ -84,17 +84,16 @@ tests = "lexer" :- [
],
"punctuation" :- [
acceptsWith' "({[:,::]})"
acceptsWith' "({[:,]})"
[P LParen, P LBrace, P LSquare,
P Colon, P Comma, P DblColon,
P Colon, P Comma,
P RSquare, P RBrace, P RParen],
acceptsWith' " ( { [ : , :: ] } ) "
acceptsWith' " ( { [ : , ] } ) "
[P LParen, P LBrace, P LSquare,
P Colon, P Comma, P DblColon,
P Colon, P Comma,
P RSquare, P RBrace, P RParen],
acceptsWith' "-> → => ⇒ ** × << ⊲ ∷"
[P Arrow, P Arrow, P DblArrow, P DblArrow,
P Times, P Times, P Triangle, P Triangle, P DblColon],
acceptsWith' "→ ⇒ × ⊲ ∷"
[P Arrow, P DblArrow, P Times, P Triangle, P DblColon],
acceptsWith' "_" [P Wild]
],
@ -119,14 +118,12 @@ tests = "lexer" :- [
],
"keywords" :- [
acceptsWith' "fun" [K Fun],
acceptsWith' "λ" [K Fun],
acceptsWith' "λ" [K Lam],
acceptsWith' "let" [K Let],
acceptsWith' "in" [K In],
acceptsWith' "case" [K Case],
acceptsWith' "of" [K Of],
acceptsWith' "ω" [K Omega],
acceptsWith' "#" [K Omega],
acceptsWith' "funk" [Name "funk"]
],
@ -134,21 +131,6 @@ tests = "lexer" :- [
acceptsWith' "0" [N Zero],
acceptsWith' "1" [N One],
acceptsWith' "2" [N $ Other 2],
acceptsWith' "69" [N $ Other 69],
acceptsWith' "1_000" [N $ Other 1000],
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"
acceptsWith' "69" [N $ Other 69]
]
]