CurryInfo: currypp-3.2.0 / CPP.ICode.Parser.SQL.Converter

 
This module implements the Interface for the CurryPP Translator.
To provide the tranformation of SQL-statements it calls in this order:
Scanner
Parser
Consistency check
Type check
Translator (to functions of CDBI interface)
Reads the .info file which contains information about the data model and
passes the information to the corresponding subroutines.
Aborts compilation process in case a stage returns with an error.

@author Julia Krone
---------------------------------------------------------------------------

 CPP.ICode.Parser.SQL.Converter

 parseSQL readParserInfo

 

module CPP.ICode.Parser.SQL.Converter
  ( parseSQL, readParserInfo, ParserInfo )
 where


import Control.Monad (when)
import System.IO     (openFile, IOMode(..), hGetContents)

import CPP.ICode.ParseTypes

import CPP.ICode.Parser.SQL.Consistency
import CPP.ICode.Parser.SQL.Namer
import CPP.ICode.Parser.SQL.Parser
import CPP.ICode.Parser.SQL.ParserInfoType
import CPP.ICode.Parser.SQL.Scanner
import CPP.ICode.Parser.SQL.Translator
import CPP.ICode.Parser.SQL.Typer


--- Converts a string representing SQL-requests into functions defined
--- in the CDBI interface by calling the different stage of transformation.
--- @param withrundb - decorate target code with `runWithDB`
--- @param parserInfo - either the parser information or an error message
--- @param pos - Position of the integrated SQL-String in the orginal file
--- @param code - the SQL-request as string
--- @return A String in Curry-Syntax (CDBI-functions).
parseSQL :: Bool -> Either String ParserInfo -> LangParser
parseSQL withrundb parserInfo pos code =
   case parserInfo of
     Left err -> return (throwPM pos err)
     Right pi -> processCompilation withrundb pi pos code

--- Reader for parser information file.
--- @param verb - verbosity level
--- @param filename - path/name of the .info file
--- @return either an error message or the parser information
readParserInfo :: Int -> String -> IO (Either String ParserInfo)
readParserInfo verb filename = do
  when (verb > 0) $ putStrLn $
    "Reading SQL model info file '" ++ filename ++ "'..."
  handle <- openFile filename ReadMode
  contents <- hGetContents handle
  case reads contents of
    []        -> return (Left "ParserInfo file not found or corrupted.")
    ((a,_):_) -> return (Right a)

-- auxiliary function to check Result after each stage
checkResult :: PM a -> Either (PM String) (PM a)
checkResult (PM (WM (Errors err) ws)) = Left (PM $ WM (throwPR err) ws)
checkResult pm@(PM (WM (OK _ ) _))    = Right pm

-- Calls the stages of parsing process in the right order
-- and passes corresponding parts of the parser information.
-- Aborts process in case a stage returns with an error.
processCompilation :: Bool -> ParserInfo -> LangParser
processCompilation withrundb parserInfo pos code =
  let parsedCode = parseTkLs pos (scan code)
  in case checkResult parsedCode of
      Left pm -> return pm
      Right _ -> callNamer parsedCode
   where callNamer res =
          let namedCode = nameStatements res pos
           in case checkResult namedCode of
                     Left pm -> return pm
                     Right _ -> callConsistency namedCode
         callConsistency res =
          let consCheckedCode = checkConsistency res
                                                 parserInfo
                                                 pos
           in case checkResult consCheckedCode of
                     Left pm -> return pm
                     Right _ -> callTyper consCheckedCode
         callTyper res =
          let typeCheckedCode = checkTypes res
                                           (getTypes parserInfo)
                                            pos
           in case checkResult typeCheckedCode of
                     Left pm -> return pm
                     Right _ -> return (translate typeCheckedCode
                                                  withrundb
                                                  (cdbiModule parserInfo)
                                                  pos)

 CPP.ICode.Parser.SQL.ParserInfoType.ParserInfo

 safe