implementation module lex
-from Text import class Text, instance Text String
import Control.Monad
import Data.Either
-import Data.Functor
-import Data.List
+import Data.Maybe
+import Data.Map
import StdString
import StdBool
+import StdList
+import StdChar
import StdFile
import System.CommandLine
import qualified Text
-Start :: *World -> *World
-Start w
-# (out, w) = stdio w
-# (toparse, out) = readEntireFile out
-# (_, w) = fclose (out <<< "\n" <<< toString (lexer toparse)) w
-= w
+SingleCharTokens :: Map Char Token
+SingleCharTokens = fromList [
+ ('(', BraceOpenToken), (')', BraceCloseToken), ('{', CBraceOpenToken),
+ ('}', CBraceCloseToken), ('[', SquareOpenToken), (']', SquareCloseToken),
+ (',', CommaToken), (':', ColonToken), (';', SColonToken),
+ ('.', DotToken), ('+', PlusToken), ('-', DashToken), ('*', StarToken),
+ ('/', SlashToken), ('%', PercentToken), ('=', AssignmentToken),
+ ('<', LesserToken), ('>', BiggerToken), ('!', ExclamationToken)]
-readEntireFile :: *File -> *([Char], *File)
-readEntireFile f
-# (b, c, f) = freadc f
-| not b = ([], f)
-# (cs, f) = readEntireFile f
-= ([c:cs], f)
+EscapeMap :: Map Char Char
+EscapeMap = fromList [
+ ('a', toChar 7), ('b', '\b'), ('f', '\f'), ('n', '\n'), ('r', '\r'),
+ ('t', '\t'), ('v', '\v')]
lexer :: [Char] -> LexerOutput
lexer [] = Right []
(Right t, rest) = lexer rest >>= \ts.Right [t:ts]
(Left e, _) = Left e
-untilNext :: [Char] -> [Char]
-untilNext [] = []
-untilNext ['*':'/':rest] = rest
-untilNext [x:rest] = untilNext rest
-
lex :: [Char] -> (Either String Token, [Char])
lex [] = (Right EndOfFileToken, [])
//Comments
-lex ['/':'/':rest] = lex (tl (dropWhile ((<>) '\n') rest))
-lex ['/':'*':rest] = lex (untilNext rest)
+lex ['/':'/':x:rest] = if (x == '\n') (lex rest) (lex ['/':'/':rest])
+lex ['/':'*':x1:x2:rest] = if (x1 == '*' && x2 == '/')
+ (lex rest) (lex ['/':'*':rest])
//Keyword tokens
lex ['v':'a':'r':rest] = (Right VarToken, rest)
lex ['V':'o':'i':'d':rest] = (Right VoidToken, rest)
lex ['B':'o':'o':'l':rest] = (Right BoolTypeToken, rest)
//Two character tokens
lex [':':':':rest] = (Right DoubleColonToken, rest)
+lex ['!':'=':rest] = (Right NotEqualToken, rest)
lex ['<':'=':rest] = (Right LesserEqToken, rest)
lex ['>':'=':rest] = (Right GreaterEqToken, rest)
lex ['=':'=':rest] = (Right EqualsToken, rest)
lex ['|':'|':rest] = (Right PipesToken, rest)
lex ['-':'>':rest] = (Right ArrowToken, rest)
//One character tokens
-lex ['(':rest] = (Right BraceOpenToken, rest)
-lex [')':rest] = (Right BraceCloseToken, rest)
-lex ['{':rest] = (Right CBraceOpenToken, rest)
-lex ['}':rest] = (Right CBraceCloseToken, rest)
-lex ['[':rest] = (Right SquareOpenToken, rest)
-lex [']':rest] = (Right SquareCloseToken, rest)
-lex [',':rest] = (Right CommaToken, rest)
-lex [':':rest] = (Right ColonToken, rest)
-lex [';':rest] = (Right SColonToken, rest)
-lex ['.':rest] = (Right DotToken, rest)
-lex ['+':rest] = (Right PlusToken, rest)
-lex ['-':rest] = (Right DashToken, rest)
-lex ['*':rest] = (Right StarToken, rest)
-lex ['/':rest] = (Right SlashToken, rest)
-lex ['%':rest] = (Right PercentToken, rest)
-lex ['=':rest] = (Right AssignmentToken, rest)
-lex ['<':rest] = (Right LesserToken, rest)
-lex ['>':rest] = (Right BiggerToken, rest)
-lex ['!':rest] = (Right ExclamationToken, rest)
//Value tokens
lex ['\'':x:'\'':rest] = (Right (CharToken x), rest)
-lex ['\'':'\\':x:'\'':rest] = case x of
- 'a' = (Right (CharToken (toChar 7)), rest) //Alarm
- 'b' = (Right (CharToken '\b'), rest) //Backspace
- 'f' = (Right (CharToken '\f'), rest) //Formfeed
- 'n' = (Right (CharToken '\n'), rest) //Newline
- 'r' = (Right (CharToken '\r'), rest) //Carriage Return
- 't' = (Right (CharToken '\t'), rest) //Horizontal tab
- 'v' = (Right (CharToken '\v'), rest) //Vertical tab
+lex ['\'':'\\':x:'\'':rest] = case get x EscapeMap of
+ Just t = (Right (CharToken t), rest)
_ = (Left ("Unknown escape: \\" +++ toString x), [])
-lex [x:xs]
-| isSpace x = lex xs
-| isDigit x = let (is, rest) = span isDigit xs in
- (Right (NumberToken [x:is]), rest)
-| isAlpha x = let (is, rest) = span (\c.isAlphanum c || c == '_') xs in
- (Right (IdentToken [x:is]), rest)
+lex [x:rest]
+# t = get x SingleCharTokens
+| isJust t = (Right (fromJust t), rest)
+| isSpace x = lex rest
+| isDigit x = let (is, rest`) = span isDigit rest in
+ (Right (NumberToken [x:is]), rest`)
+| isAlpha x = let (is, rest`) = span (\c.isAlphanum c || c == '_') rest in
+ (Right (IdentToken [x:is]), rest`)
| otherwise = (Left ("Unexpected character: " +++ toString x), [])
-
-instance toString LexerOutput where
- toString (Left l) = "Error: " +++ l
- toString (Right x) = 'Text'.concat (print 0 x)
-
-tab :: Int -> [String]
-tab i = replicate i "\t"
-
-print :: Int [Token] -> [String]
-print _ [] = []
-print i [(IdentToken l):rest] = [toString l:print i rest]
-print i [(NumberToken j):rest] = [toString j:print i rest]
-print i [(CharToken c):rest] = ["'":toString c:"'":print i rest]
-print i [VarToken:rest] = ["var ":print i rest]
-print i [ReturnToken:rest] = ["return ":print i rest]
-print i [IfToken:rest] = ["if":print i rest]
-print i [ElseToken:rest] = ["else":print i rest]
-print i [WhileToken:rest] = ["while":print i rest]
-print i [TrueToken:rest] = ["True":print i rest]
-print i [FalseToken:rest] = ["False":print i rest]
-print i [VoidToken:rest] = ["Void":print i rest]
-print i [IntTypeToken:rest] = ["Int":print i rest]
-print i [CharTypeToken:rest] = ["Char":print i rest]
-print i [BoolTypeToken:rest] = ["Bool":print i rest]
-print i [DoubleColonToken:rest] = [" :: ":print i rest]
-print i [LesserEqToken:rest] = [" <= ":print i rest]
-print i [GreaterEqToken:rest] = [" >= ":print i rest]
-print i [EqualsToken:rest] = [" == ":print i rest]
-print i [AmpersandsToken:rest] = [" && ":print i rest]
-print i [PipesToken:rest] = [" || ":print i rest]
-print i [ArrowToken:rest] = [" -> ":print i rest]
-print i [BraceOpenToken:rest] = ["(":print i rest]
-print i [BraceCloseToken:rest] = [")":print i rest]
-print i [CBraceOpenToken:rest] = ["{\n":tab (i+1)] ++ print (i+1) rest
-print i [CBraceCloseToken:rest] = case rest of
- [CBraceCloseToken:_] = ["}\n":tab (i-2)] ++ print (i-1) rest
- _ = ["}\n":tab (i-1)] ++ print (i-1) rest
-print i [SquareOpenToken:rest] = ["[":print i rest]
-print i [SquareCloseToken:rest] = ["]":print i rest]
-print i [CommaToken:rest] = [", ":print i rest]
-print i [ColonToken:rest] = [":":print i rest]
-print i [SColonToken:rest] = case rest of
- [CBraceCloseToken:_] = [";\n":tab (i-1)] ++ print i rest
- _ = [";\n":tab i] ++ print i rest
-print i [DotToken:rest] = [".":print i rest]
-print i [PlusToken:rest] = [" + ":print i rest]
-print i [DashToken:rest] = [" - ":print i rest]
-print i [StarToken:rest] = [" * ":print i rest]
-print i [SlashToken:rest] = [" / ":print i rest]
-print i [PercentToken:rest] = [" % ":print i rest]
-print i [AssignmentToken:rest] = [" = ":print i rest]
-print i [LesserToken:rest] = [" < ":print i rest]
-print i [BiggerToken:rest] = [" > ":print i rest]
-print i [ExclamationToken:rest] = ["!":print i rest]
-print i [EndOfFileToken:rest] = ["\n":print i rest]
repositories / cc1516.git / blobdiff