src/Language/Fay.hs

{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings     #-}
{-# LANGUAGE RecordWildCards       #-}
{-# LANGUAGE TypeSynonymInstances  #-}
{-# LANGUAGE ViewPatterns          #-}

module Language.Fay
  (module Language.Fay.Types
  ,compileFile
  ,compileFileWithState
  ,compileFromTo
  ,compileFromToAndGenerateHtml
  ,toJsName
  ,showCompileError)
   where

import           Language.Fay.Compiler        (compileToplevelModule,
                                               compileViaStr)
import           Language.Fay.Compiler.Misc   (printSrcLoc)
import           Language.Fay.Compiler.Packages
import           Language.Fay.Print
import           Language.Fay.Types

import           Control.Applicative
import           Control.Monad
import           Data.List
import           Language.Haskell.Exts        (prettyPrint)
import           Language.Haskell.Exts.Syntax
import           Paths_fay
import           System.FilePath

-- | Compile the given file and write the output to the given path, or
-- if nothing given, stdout.
compileFromTo :: CompileConfig -> FilePath -> Maybe FilePath -> IO ()
compileFromTo config filein fileout = do
  result <- maybe (compileFile config filein)
                  (compileFromToAndGenerateHtml config filein)
                  fileout
  case result of
    Right out -> maybe (putStrLn out) (flip writeFile out) fileout
    Left err -> error $ showCompileError $ err

-- | Compile the given file and write to the output, also generate any HTML.
compileFromToAndGenerateHtml :: CompileConfig -> FilePath -> FilePath -> IO (Either CompileError String)
compileFromToAndGenerateHtml config filein fileout = do
  result <- compileFile config { configFilePath = Just filein } filein
  case result of
    Right out -> do
      when (configHtmlWrapper config) $
        writeFile (replaceExtension fileout "html") $ unlines [
            "<!doctype html>"
          , "<html>"
          , "  <head>"
          ,"    <meta http-equiv='Content-Type' content='text/html; charset=utf-8'>"
          , unlines . map ("    "++) . map makeScriptTagSrc $ configHtmlJSLibs config
          , "    " ++ makeScriptTagSrc relativeJsPath
          , "    </script>"
          , "  </head>"
          , "  <body>"
          , "  </body>"
          , "</html>"]
      return (Right out)
            where relativeJsPath = makeRelative (dropFileName fileout) fileout
                  makeScriptTagSrc :: FilePath -> String
                  makeScriptTagSrc = \s ->
                    "<script type=\"text/javascript\" src=\"" ++ s ++ "\"></script>"
    Left err -> return (Left err)

-- | Compile the given file.
compileFile :: CompileConfig -> FilePath -> IO (Either CompileError String)
compileFile config filein = do
  either Left (Right . fst) <$> compileFileWithState config filein

compileFileWithState :: CompileConfig -> FilePath -> IO (Either CompileError (String,CompileState))
compileFileWithState config filein = do
  runtime <- getDataFileName "js/runtime.js"
  hscode <- readFile filein
  raw <- readFile runtime
  config' <- resolvePackages config
  compileToModule filein config' raw compileToplevelModule hscode

-- | Compile the given module to a runnable module.
compileToModule :: (Show from,Show to,CompilesTo from to)
                => FilePath
                -> CompileConfig -> String -> (from -> Compile to) -> String
                -> IO (Either CompileError (String,CompileState))
compileToModule filepath config raw with hscode = do
  result <- compileViaStr filepath config with hscode
  case result of
    Left err -> return (Left err)
    Right (PrintState{..},state) ->
      return $ Right $ (generate (concat (reverse psOutput))
                                 (stateExports state)
                                 (stateModuleName state), state)

  where generate jscode exports (ModuleName (clean -> modulename)) = unlines
          ["/** @constructor"
          ,"*/"
          ,"var " ++ modulename ++ " = function(){"
          ,raw
          ,jscode
          ,"// Exports"
          ,unlines (map printExport exports)
          ,"// Built-ins"
          ,"this._ = _;"
          ,if configExportBuiltins config
              then unlines ["this.$           = $;"
                           ,"this.$fayToJs    = Fay$$fayToJs;"
                           ,"this.$jsToFay    = Fay$$jsToFay;"
                           ]
              else ""
          ,"};"
          ,if not (configLibrary config)
              then unlines [";"
                           ,"var main = new " ++ modulename ++ "();"
                           ,"main._(main." ++ modulename ++ "$main);"
                           ]
              else ""
          ]
        clean ('.':cs) = '$' : clean cs
        clean (c:cs)   = c : clean cs
        clean [] = []

-- | Print an this.x = x; export out.
printExport :: QName -> String
printExport name =
  printJSString (JsSetProp JsThis
                           (JsNameVar name)
                           (JsName (JsNameVar name)))

-- | Convert a Haskell filename to a JS filename.
toJsName :: String -> String
toJsName x = case reverse x of
  ('s':'h':'.': (reverse -> file)) -> file ++ ".js"
  _ -> x

-- | Print a compile error for human consumption.
showCompileError :: CompileError -> String
showCompileError e = case e of
  ParseError _ err -> err
  UnsupportedDeclaration d -> "unsupported declaration: " ++ prettyPrint d
  UnsupportedExportSpec es -> "unsupported export specification: " ++ prettyPrint es
  UnsupportedMatchSyntax m -> "unsupported match/binding syntax: " ++ prettyPrint m
  UnsupportedWhereInMatch m -> "unsupported `where' syntax: " ++ prettyPrint m
  UnsupportedWhereInAlt alt -> "`where' not supported here: " ++ prettyPrint alt
  UnsupportedExpression expr -> "unsupported expression syntax: " ++ prettyPrint expr
  UnsupportedQualStmt stmt -> "unsupported list qualifier: " ++ prettyPrint stmt
  UnsupportedLiteral lit -> "unsupported literal syntax: " ++ prettyPrint lit
  UnsupportedLetBinding d -> "unsupported let binding: " ++ prettyPrint d
  UnsupportedOperator qop -> "unsupported operator syntax: " ++ prettyPrint qop
  UnsupportedPattern pat -> "unsupported pattern syntax: " ++ prettyPrint pat
  UnsupportedRhs rhs -> "unsupported right-hand side syntax: " ++ prettyPrint rhs
  UnsupportedGuardedAlts ga -> "unsupported guarded alts: " ++ prettyPrint ga
  EmptyDoBlock -> "empty `do' block"
  UnsupportedModuleSyntax{} -> "unsupported module syntax (may be supported later)"
  LetUnsupported -> "let not supported here"
  InvalidDoBlock -> "invalid `do' block"
  RecursiveDoUnsupported -> "recursive `do' isn't supported"
  FfiNeedsTypeSig d -> "your FFI declaration needs a type signature: " ++ prettyPrint d
  FfiFormatBadChars cs -> "invalid characters for FFI format string: " ++ show cs
  FfiFormatNoSuchArg i -> "no such argument in FFI format string: " ++ show i
  FfiFormatIncompleteArg -> "incomplete `%' syntax in FFI format string"
  FfiFormatInvalidJavaScript srcloc code err ->
    printSrcLoc srcloc ++ ":" ++
    "\ninvalid JavaScript code in FFI format string:\n"
                                         ++ err ++ "\nin " ++ code
  UnsupportedFieldPattern p -> "unsupported field pattern: " ++ prettyPrint p
  UnsupportedImport i -> "unsupported import syntax, we're too lazy: " ++ prettyPrint i
  Couldn'tFindImport i places ->
    "could not find an import in the path: " ++ prettyPrint i ++ ", \n" ++
    "searched in these places: " ++ intercalate ", " places
  UnableResolveUnqualified name -> "unable to resolve unqualified name " ++ prettyPrint name
  UnableResolveQualified qname -> "unable to resolve qualified names " ++ prettyPrint qname
  UnableResolveCachedImport name -> "unable to resolve cached import " ++ prettyPrint name