{
-- alex scanner for use with uulib
--   compile with alex -o Scanner.hs -g Scanner.x
module Graphics.LambdaCube.Loader.Generated.CompositorScriptScanner(tokenize) where

import UU.Scanner
}

$litChar   = [^[\" \\]]
$identChar = [a-zA-Z0-9_\.\-\/\~\&]


tokens :-
  $white+                                      ;                               -- whitespace
  "//".*                                       ;                               -- comment

  \" ($litChar | \\ \\ | \\ \" )* \"           { valueToken TkString }         -- string
  [0-9]+                                       { valueToken TkInteger10 }      -- int
  [0-9]+\.[0-9]+                               { valueToken TkFraction }       -- float
  
  ( 
    on | off |
    compositor | technique | texture | target_width | target_height | target_width_scaled | target_height_scaled | shared |
    PF_A8R8G8B8 | PF_R8G8B8A8 | PF_R8G8B8 | PF_FLOAT16_RGBA | PF_FLOAT16_RGB | PF_FLOAT16_R | PF_FLOAT32_RGBA | PF_FLOAT32_RGB | PF_FLOAT32_R | 
    target | target_output | input | none | previous | only_initial | visibility_mask | lod_bias | shadows | material_scheme |
    pass | render_quad | clear | stencil | render_scene | material |  identifier | first_render_queue | last_render_queue |
    buffers | colour | depth | colour_value | depth_value | stencil_value | check | comp_func |
    always_fail | always_pass | less | less_equal | not_equal | greater_equal | greater | ref_value | mask | fail_op |
    keep | zero | replace | increment | decrement | increment_wrap | decrement_wrap | invert | depth_fail_op | pass_op | two_sided
  )                                            { reserved }                    -- reserved keywords
  [\{\}]                                       { reserved }                    -- reserved symbols

  $identChar+                                  { valueToken TkVarid }          -- identifier


{
-- boilerplate code needed for Alex
type AlexInput = (Pos, String)

alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar = error "alexInputPrevChar: there is no need to go back in the input."

alexGetChar :: AlexInput -> Maybe (Char, AlexInput)
alexGetChar (_, []) = Nothing
alexGetChar (p, (c:cs))
  = let p' = adv p c
    in Just (c, (p', cs))

-- use the Alex scanner to generate a list of tokens for the uulib token parsers
tokenize :: String -> String -> [Token]
tokenize filename str
  = go (initpos, str)
  where
    initpos = Pos 1 1 filename
    
    go inp@(pos, cs)
      = case alexScan inp 0 of
          AlexEOF         -> []
          AlexError inp'  -> valueToken TkError [head cs] pos : go inp'
          AlexSkip inp' _ -> go inp'
          AlexToken inp' len act -> act (take len cs) pos : go inp'
}