Lexer.x

{
module Lexer98 ( scanTokens ) where

import Data.Text (Text)
import qualified Data.Text as Text

}

%wrapper "basic"

$special        = [ \( \) \, \; \[ \] \` \{ \} ]
$return         = \r
$linefeed       = \n
$vertab         = \v
$formfeed       = \f
$space          = \ 
$tab            = \t
$ascSmall       = [a-z]
$small          = [$ascSmall \_]
$ascLarge       = [A-Z]
$large          = [$ascLarge \_]
$ascDigit       = [0..9]
$octit          = [0..8]
$ascSymbol      = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~]
$symbol         = $ascSymbol
$digit          = $ascDigit
$hexit          = [0-9a-fA-F]
@whitespace     = $white
@newline        = $return $linefeed | $return | $linefeed | $formfeed
@graphic        = $small | $large | $symbol | $digit | $special | [\:\"\']
@any            = @graphic | $space | $tab


$dash           = \-
@dashes         = $dash $dash+
@comment        = @dashes .* $linefeed
@opencom        = \{ \-
@closecom       = \- \}

@reservedop     = ".." | \: | "::" | \= | \\ | "<-" | "->" | \@ | \~ | "=>"

@decimal	= $digit+
@octal		= $octit+
@hexadecimal	= $hexit+
@integer        = @decimal | \0 [oO] @octal | 0 [xX] @hexadecimal

@exponent       = [eE] [\+\-] @decimal
@float          = @decimal \. @decimal @exponent?
                | @decimal @exponent

$charesc        = [abfnrtv\\\"'&]
$cntrl          = [A-Z@\[\\\]\^_]

@ascii          = \^ $cntrl
                | NUL | SOH | STX | ETX | EOT | ENQ | ACK | BEL
                | BS  | HT  | LF  | VT  | FF  | CR  | SO  | SI
                | DLE | DC1 | DC2 | DC3 | DC4 | NAK | SYN | ETB
                | CAN | EM  | SUB | ESC | FS  | GS  | RS  | US
                | SP  | DEL

@escape         =   $charesc
                |   @ascii
                |   @decimal
                | o @octal
                | x @hexadecimal

@gap            = \\ $white+ \\

@char           = \' (@graphic (\'{0} | \\'{0}) | $space | (@escape \\{0} \&{0})) \'
@string         = \" (@graphic (\"{0} | \\'{0}) | $space | @escape | @gap)* \"

@reservedid     = case | class | data | default | deriving | do
                | else | if | import | in | infix | infixr
                | infixl | instance | let | module | newtype
                | of | then | type | where | \_

@varid          = ($small ($small | $large | $digit | \')*) @reservedid{0}
@conid          = $large ($small | $large | $digit | \`)*
@varsym         = $symbol ($symbol | \:)* @reservedid{0} @dashes{0}
@consym         = \: ($symbol | \:)* @reservedid{0}
@literal        = @integer | @float | @char | @string

@tyvar          = @varid
@tycon          = @conid
@tycls          = @conid
@modid          = @conid
@qvarid         = (modid \.)? varid
@qconid         = (modid \.)? conid
@qtycon         = (modid \.)? tycon
@qtycls         = (modid \.)? tycls
@qvarsym        = (modid \.)? varsym
@qconsym        = (modid \.)? consym

haskell98 :-

$white;

{
  main = pure ()
}