-module lex
-
-:: Token
- //Values
- = IdentToken String // Identifier
- | NumberToken Int // Integer
- //Keywords
- | VarToken // var keyword
- | VoidToken // void keyword
- | ReturnToken // return keyword
- | IfToken // if keyword
- | ElseToken // else keyword
- | WhileToken // while keyword
- | TrueToken // True keyword
- | FalseToken // False keyword
- //Single Characters
- | BraceOpenToken // (
- | BraceCloseToken // )
- | CBraceOpenToken // {
- | CBraceCloseToken // {
- | SquareOpenToken // [
- | SquareCloseToken // ]
- | CommaToken // ,
- | ColonToken // :
- | SColonToken // ;
- | DotToken // .
- | PlusToken // +
- | DashToken // -
- | StarToken // *
- | SlashToken // /
- | PercentToken // %
- | EqualsToken // =
- | LesserToken // <
- | BiggerToken // >
- | ExclamationToken // !
- | AmpersandToken // &
- | PipeToken // |
- | SingleQuoteToken // '
-
-Start = "Hello World!\n"
+implementation module lex
+
+from Text import class Text, instance Text String
+import Control.Monad
+import Data.Either
+import Data.Functor
+import Data.List
+import StdString
+import StdBool
+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
+
+readEntireFile :: *File -> *([Char], *File)
+readEntireFile f
+# (b, c, f) = freadc f
+| not b = ([], f)
+# (cs, f) = readEntireFile f
+= ([c:cs], f)
+
+lexer :: [Char] -> LexerOutput
+lexer [] = Right []
+lexer x = case lex x of
+ (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)
+//Keyword tokens
+lex ['v':'a':'r':rest] = (Right VarToken, rest)
+lex ['V':'o':'i':'d':rest] = (Right VoidToken, rest)
+lex ['r':'e':'t':'u':'r':'n':rest] = (Right ReturnToken, rest)
+lex ['i':'f':rest] = (Right IfToken, rest)
+lex ['e':'l':'s':'e':rest] = (Right ElseToken, rest)
+lex ['w':'h':'i':'l':'e':rest] = (Right WhileToken, rest)
+lex ['T':'r':'u':'e':rest] = (Right TrueToken, rest)
+lex ['F':'a':'l':'s':'e':rest] = (Right FalseToken, rest)
+lex ['I':'n':'t':rest] = (Right IntTypeToken, rest)
+lex ['C':'h':'a':'r':rest] = (Right CharTypeToken, rest)
+lex ['B':'o':'o':'l':rest] = (Right BoolTypeToken, rest)
+//Two character tokens
+lex [':':':':rest] = (Right DoubleColonToken, rest)
+lex ['<':'=':rest] = (Right LesserEqToken, rest)
+lex ['>':'=':rest] = (Right GreaterEqToken, rest)
+lex ['=':'=':rest] = (Right EqualsToken, rest)
+lex ['&':'&':rest] = (Right AmpersandsToken, 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
+ _ = (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)
+| 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