diff --git a/GPL b/GPL new file mode 100644 --- /dev/null +++ b/GPL @@ -0,0 +1,341 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. By contrast, the GNU General Public +License is intended to guarantee your freedom to share and change free +software--to make sure the software is free for all its users. This +General Public License applies to most of the Free Software +Foundation's software and to any other program whose authors commit to +using it. (Some other Free Software Foundation software is covered by +the GNU Library General Public License instead.) You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish), that you receive source code or can get it +if you want it, that you can change the software or use pieces of it +in new free programs; and that you know you can do these things. + + To protect your rights, we need to make restrictions that forbid +anyone to deny you these rights or to ask you to surrender the rights. +These restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must give the recipients all the rights that +you have. You must make sure that they, too, receive or can get the +source code. And you must show them these terms so they know their +rights. + + We protect your rights with two steps: (1) copyright the software, and +(2) offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + + Also, for each author's protection and ours, we want to make certain +that everyone understands that there is no warranty for this free +software. If the software is modified by someone else and passed on, we +want its recipients to know that what they have is not the original, so +that any problems introduced by others will not reflect on the original +authors' reputations. + + Finally, any free program is threatened constantly by software +patents. We wish to avoid the danger that redistributors of a free +program will individually obtain patent licenses, in effect making the +program proprietary. To prevent this, we have made it clear that any +patent must be licensed for everyone's free use or not licensed at all. + + The precise terms and conditions for copying, distribution and +modification follow. + + GNU GENERAL PUBLIC LICENSE + TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION + + 0. This License applies to any program or other work which contains +a notice placed by the copyright holder saying it may be distributed +under the terms of this General Public License. The "Program", below, +refers to any such program or work, and a "work based on the Program" +means either the Program or any derivative work under copyright law: +that is to say, a work containing the Program or a portion of it, +either verbatim or with modifications and/or translated into another +language. (Hereinafter, translation is included without limitation in +the term "modification".) Each licensee is addressed as "you". + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + + 1. You may copy and distribute verbatim copies of the Program's +source code as you receive it, in any medium, provided that you +conspicuously and appropriately publish on each copy an appropriate +copyright notice and disclaimer of warranty; keep intact all the +notices that refer to this License and to the absence of any warranty; +and give any other recipients of the Program a copy of this License +along with the Program. + +You may charge a fee for the physical act of transferring a copy, and +you may at your option offer warranty protection in exchange for a fee. + + 2. You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + + a) You must cause the modified files to carry prominent notices + stating that you changed the files and the date of any change. + + b) You must cause any work that you distribute or publish, that in + whole or in part contains or is derived from the Program or any + part thereof, to be licensed as a whole at no charge to all third + parties under the terms of this License. + + c) If the modified program normally reads commands interactively + when run, you must cause it, when started running for such + interactive use in the most ordinary way, to print or display an + announcement including an appropriate copyright notice and a + notice that there is no warranty (or else, saying that you provide + a warranty) and that users may redistribute the program under + these conditions, and telling the user how to view a copy of this + License. (Exception: if the Program itself is interactive but + does not normally print such an announcement, your work based on + the Program is not required to print an announcement.) + +These requirements apply to the modified work as a whole. If +identifiable sections of that work are not derived from the Program, +and can be reasonably considered independent and separate works in +themselves, then this License, and its terms, do not apply to those +sections when you distribute them as separate works. But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + + 3. You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + + a) Accompany it with the complete corresponding machine-readable + source code, which must be distributed under the terms of Sections + 1 and 2 above on a medium customarily used for software interchange; or, + + b) Accompany it with a written offer, valid for at least three + years, to give any third party, for a charge no more than your + cost of physically performing source distribution, a complete + machine-readable copy of the corresponding source code, to be + distributed under the terms of Sections 1 and 2 above on a medium + customarily used for software interchange; or, + + c) Accompany it with the information you received as to the offer + to distribute corresponding source code. (This alternative is + allowed only for noncommercial distribution and only if you + received the program in object code or executable form with such + an offer, in accord with Subsection b above.) + +The source code for a work means the preferred form of the work for +making modifications to it. For an executable work, complete source +code means all the source code for all modules it contains, plus any +associated interface definition files, plus the scripts used to +control compilation and installation of the executable. However, as a +special exception, the source code distributed need not include +anything that is normally distributed (in either source or binary +form) with the major components (compiler, kernel, and so on) of the +operating system on which the executable runs, unless that component +itself accompanies the executable. + +If distribution of executable or object code is made by offering +access to copy from a designated place, then offering equivalent +access to copy the source code from the same place counts as +distribution of the source code, even though third parties are not +compelled to copy the source along with the object code. + + 4. You may not copy, modify, sublicense, or distribute the Program +except as expressly provided under this License. Any attempt +otherwise to copy, modify, sublicense or distribute the Program is +void, and will automatically terminate your rights under this License. +However, parties who have received copies, or rights, from you under +this License will not have their licenses terminated so long as such +parties remain in full compliance. + + 5. You are not required to accept this License, since you have not +signed it. However, nothing else grants you permission to modify or +distribute the Program or its derivative works. These actions are +prohibited by law if you do not accept this License. Therefore, by +modifying or distributing the Program (or any work based on the +Program), you indicate your acceptance of this License to do so, and +all its terms and conditions for copying, distributing or modifying +the Program or works based on it. + + 6. Each time you redistribute the Program (or any work based on the +Program), the recipient automatically receives a license from the +original licensor to copy, distribute or modify the Program subject to +these terms and conditions. You may not impose any further +restrictions on the recipients' exercise of the rights granted herein. +You are not responsible for enforcing compliance by third parties to +this License. + + 7. If, as a consequence of a court judgment or allegation of patent +infringement or for any other reason (not limited to patent issues), +conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot +distribute so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you +may not distribute the Program at all. For example, if a patent +license would not permit royalty-free redistribution of the Program by +all those who receive copies directly or indirectly through you, then +the only way you could satisfy both it and this License would be to +refrain entirely from distribution of the Program. + +If any portion of this section is held invalid or unenforceable under +any particular circumstance, the balance of the section is intended to +apply and the section as a whole is intended to apply in other +circumstances. + +It is not the purpose of this section to induce you to infringe any +patents or other property right claims or to contest validity of any +such claims; this section has the sole purpose of protecting the +integrity of the free software distribution system, which is +implemented by public license practices. Many people have made +generous contributions to the wide range of software distributed +through that system in reliance on consistent application of that +system; it is up to the author/donor to decide if he or she is willing +to distribute software through any other system and a licensee cannot +impose that choice. + +This section is intended to make thoroughly clear what is believed to +be a consequence of the rest of this License. + + 8. If the distribution and/or use of the Program is restricted in +certain countries either by patents or by copyrighted interfaces, the +original copyright holder who places the Program under this License +may add an explicit geographical distribution limitation excluding +those countries, so that distribution is permitted only in or among +countries not thus excluded. In such case, this License incorporates +the limitation as if written in the body of this License. + + 9. The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and "any +later version", you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + + 10. If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + + NO WARRANTY + + 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY +FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN +OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES +PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED +OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS +TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE +PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, +REPAIR OR CORRECTION. + + 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR +REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING +OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED +TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY +YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER +PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE +POSSIBILITY OF SUCH DAMAGES. + + END OF TERMS AND CONDITIONS + + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) 19yy + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) 19yy name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Library General +Public License instead of this License. diff --git a/HESQL.hs b/HESQL.hs new file mode 100644 --- /dev/null +++ b/HESQL.hs @@ -0,0 +1,34 @@ +module Main (main) where + +import System.Environment +import Language.Haskell.Pretty +import System.FilePath +import Language.Haskell.Pretty +import HESQL.Parser (hesqlModule) +import HESQL.Translator +import Control.Monad(when) +import Text.Parsec.String (parseFromFile) +import System.Exit + +outputFile file = replaceExtension file ".hs" + +main = do + putStrLn "hesql 0.0" + [file, db] <- getArgs + when (outputFile file == file) $ + error (file ++ "has a wrong extension") + inp <- readFile file + mod <- parseFromFile hesqlModule file + case mod of + Left err -> do + print err + exitWith $ ExitFailure 1 + Right mod' -> do + outp <- generateCode file db mod' + writeFile (outputFile file) $ + prettyPrint $ + outp + + + + diff --git a/HESQL/Parser.hs b/HESQL/Parser.hs new file mode 100644 --- /dev/null +++ b/HESQL/Parser.hs @@ -0,0 +1,186 @@ +module HESQL.Parser (hesqlModule) where + +import HESQL.Syntax +import Text.Parsec.String +import Text.Parsec +import Text.Parsec.Language (haskellDef) +import Text.Parsec.Expr +import qualified Text.Parsec.Token as P +import Data.List (intercalate) +import Database.HDBC +import Control.Monad (forM_) + + +hesqlModule :: Parser HesqlModule +hesqlModule = do + whiteSpace + modName <- moduleHeader + decls <- decls + whiteSpace + eof + return $ HesqlModule modName decls + +decls = many decl + +decl = do + fn <- funName + p <- many parameter + whiteSpace + char '=' + whiteSpace + stmt <- sqlStatement + return $ HesqlDecls fn p stmt + + + +funName = identifier +parameter = identifier + +sqlStatement = + selectStatement <|> + insertStatement <|> + updateStatement <|> + deleteStatement + + + +selectStatement = do + opts <- selectVariant + cols <- sepBy1 column (symbol ",") + reserved "from" + tab <- table + wh <- optionMaybe whereCondition + return $ SELECT opts (ExplicitColumns cols) tab + wh Nothing Nothing + +selectVariant = + select "1'" [Strict, ReturnMaybe] <|> + select "1" [ReturnMaybe] <|> + select "'" [Strict] <|> + select "" [] + +select suffix opts = + reserved ("select"++suffix) >> return opts + +insertStatement = do + reserved "insert" + reserved "into" + tab <- table + spec <- insertSpec + reserved "values" + values <- insertValues + return $ INSERT tab spec values + +updateStatement = do + reserved "update" + tab <- table + reserved "set" + updates <- updates + wh <- optionMaybe whereCondition + return $ UPDATE tab updates wh + +deleteStatement = do + reserved "delete" + reserved "from" + tab <- table + wh <- optionMaybe whereCondition + return $ DELETE tab wh + + +updates = sepBy1 set (symbol ",") + where set = do + col <- columnName + symbol "=" + e <- sqlExp + return (col, e) + + +insertSpec = + parens $ sepBy1 identifier (symbol ",") + +insertValues = + parens $ sepBy1 sqlExp (symbol ",") + +whereCondition :: Parser SqlExp +whereCondition = do + reserved "where" + be <- sqlExp + return be + +sqlExp = sqlCompare + +sqlCompare = buildExpressionParser table sqlTerm + where table = [ [prefix "not" SqlNot] + , [binary "+" SqlPlus AssocLeft, binary "-" SqlMinus AssocLeft] + , [binary "*" SqlMult AssocLeft, binary "/" SqlDiv AssocLeft] + , [binary "is" SqlIs AssocRight] + , [binary "=" SqlEqual AssocLeft, binary "<" SqlLess AssocLeft, + binary ">" SqlGreater AssocLeft] + , [binary "and" SqlAnd AssocLeft] + , [binary "or" SqlOr AssocLeft] + ] + +sqlBoolLiteral = + kw "true" (SqlLiteral (toSql True)) <|> + kw "true" (SqlLiteral (toSql True)) <|> + kw "null" (SqlLiteral SqlNull) + where kw s v = reserved s >> return v + +sqlLiteral = sqlBoolLiteral <|> + sqlStringLiteral + +sqlStringLiteral = + between (symbol "'") (symbol "'") $ do + s <- many stringChar + return (SqlLiteral (toSql (s :: String))) + where stringChar = + noneOf "\\'" <|> do + char '\\' + char '\'' -- TODO \n etc + + + + +sqlTerm = parens sqlExp <|> sqlLiteral <|> do + n <- identifier + funParams n <|> return (SqlColumn n) + + +funParams n = do + args <- parens $ sepBy sqlExp (symbol ",") + return $ SqlFunApp n args + + +columnName = identifier + +column = do + col <- identifier + return (col, Nothing) + +table = identifier + +modName = sepBy1 identifier (char '.') + +moduleHeader = do + reserved "module" + m <- modName + reserved "where" + return $ intercalate "." m + +lexer = P.makeTokenParser haskellDef + +parens = P.parens lexer +braces = P.braces lexer +identifier = P.identifier lexer +reserved = P.reserved lexer +reservedOp = P.reservedOp lexer +whiteSpace = P.whiteSpace lexer +symbol = P.symbol lexer + +binary name fun assoc = Infix (do + reservedOp name; + return $ \ e1 e2 -> SqlInfixApp e1 fun e2) + assoc + +prefix name fun = Prefix (do reservedOp name; return fun) +postfix names fun = Prefix (do forM_ names reservedOp; return fun) diff --git a/HESQL/Syntax.hs b/HESQL/Syntax.hs new file mode 100644 --- /dev/null +++ b/HESQL/Syntax.hs @@ -0,0 +1,143 @@ +module HESQL.Syntax where + +import Database.HDBC (SqlValue(..)) +import Data.List (intercalate) + +type ModuleName = String +type DeclName = String +type Vars = [String] +type TableName = String +type ColName = String +type ColAlias = String +type FunName = String + +data HesqlModule = HesqlModule ModuleName [HesqlDecls] deriving (Show) +data HesqlDecls = HesqlDecls { + declName :: DeclName + , declVars :: Vars + , declSQL :: SQL + } deriving Show + +data SQL = SELECT [SelectOption] SelectColumns From + (Maybe SqlExp) (Maybe Order) (Maybe Group) + | INSERT TableName InsertColumns [SqlExp] + | UPDATE TableName [(ColName, SqlExp)] (Maybe SqlExp) + | DELETE TableName (Maybe SqlExp) + | DummySQL + +instance Show SQL where + show = sqlToString + +data SqlExp = + SqlFunApp FunName [SqlExp] | + SqlInfixApp SqlExp SqlInfixOp SqlExp | + SqlPlaceHolder String | SqlLiteral SqlValue | SqlColumn ColName | + SqlNot SqlExp + deriving Show + +data SqlInfixOp = SqlEqual | SqlLike | SqlLess | + SqlGreater | SqlAnd | SqlOr | + SqlIs | + SqlPlus | SqlMult | SqlMinus | SqlDiv + deriving Show + +infixPrio SqlEqual = 3 +infixPrio SqlLike = 3 +infixPrio SqlLess = 3 +infixPrio SqlGreater = 3 +infixPrio SqlIs = 3 +infixPrio SqlAnd = 4 +infixPrio SqlOr = 5 +infixPrio SqlPlus = 1 +infixPrio SqlMinus = 1 +infixPrio SqlMult = 2 +infixPrio SqlDiv = 2 + + +sqlToString :: SQL -> String +sqlToString DummySQL = "" +sqlToString (SELECT _ cols from wh order group) = + "select " ++ showColumns cols ++ " from " ++ showFrom from + ++ showWhere wh +-- TODO where order group +sqlToString (INSERT tab spec vals) = + "insert into " ++ tab ++ " " ++ + (withParens $ comaSepList spec) ++ + " values " ++ + (withParens $ comaSepList $ map showSqlExp vals) + +sqlToString (UPDATE tab updates wh) = + "update " ++ tab ++ " " ++ + (comaSepList $ map updateStr updates) ++ + showWhere wh + where updateStr (col, e) = col ++ " = " ++ showSqlExp e + +sqlToString (DELETE tab wh) = + "delete from " ++ tab ++ showWhere wh + + +showColumns :: SelectColumns -> String +showColumns (ExplicitColumns cols) = comaSepList $ map fst cols -- TODO Alias +showColumns _ = todo "showColumns" + +showFrom table = table + +showWhere Nothing = "" +showWhere (Just sqlExp) = " where " ++ showSqlExp sqlExp + +showSqlExp = showSqlExp' 5 + +showSqlExp' p (SqlColumn n) = n +showSqlExp' p (SqlInfixApp a op b) = par (showSqlExp' p' a ++ " " ++ infixOpToString op ++ + " " ++ showSqlExp' p' b) + where par = if p' > p then withParens else id + p' = infixPrio op +showSqlExp' p (SqlPlaceHolder _) = "?" +showSqlExp' p (SqlFunApp f args) = f ++ (withParens $ comaSepList $ map showSqlExp args) +showSqlExp' p (SqlLiteral v) = showSqlValue v +showSqlExp' p (SqlNot e) = "not " ++ showSqlExp e + +showSqlValue (SqlBool b) = show b +showSqlValue SqlNull = "null" +showSqlValue (SqlString s) = "'" ++ s ++ "'" + +comaSepList = intercalate ", " +withParens s = "(" ++ s ++ ")" + + +todo s = error ("TODO " ++ s) + +data SelectOption = Strict | ReturnMaybe deriving (Show, Eq) +data SelectColumns = AllColumns | ExplicitColumns [(ColName, Maybe ColAlias)] deriving Show +-- data From = FromSubQuery SQL | FromTables [(TableName, TableAlias)] deriving Show +type From = TableName +type InsertColumns = [ColName] + +type TableAlias = String + +type Order = () +type Group = () + + + +infixOpToString SqlEqual = "=" +infixOpToString SqlLike = "like" +infixOpToString SqlGreater = ">" +infixOpToString SqlLess = "<" +infixOpToString SqlAnd = "and" +infixOpToString SqlOr = "or" +infixOpToString SqlIs = "is" +infixOpToString SqlPlus = "+" +infixOpToString SqlMinus = "-" +infixOpToString SqlDiv = "/" +infixOpToString SqlMult = "*" + + +isSelect (SELECT _ _ _ _ _ _) = True +isSelect _ = False + +selectOpts :: SQL -> [SelectOption] +selectOpts (SELECT opts _ _ _ _ _) = opts +selectOpts _ = [] + +selectColumns (SELECT _ cols _ _ _ _) = cols diff --git a/HESQL/Translator.hs b/HESQL/Translator.hs new file mode 100644 --- /dev/null +++ b/HESQL/Translator.hs @@ -0,0 +1,155 @@ +module HESQL.Translator (generateCode) where + +import Language.Haskell.Syntax +import Database.HDBC.PostgreSQL + +import HESQL.Syntax +import HESQL.Verifier + +import System.FilePath + + + +stmtRec = HsIdent "Stmts" +funarg = HsPVar . HsIdent +funargs = map funarg + +srcloc = SrcLoc "" 1 1 + +hsSimpleFun name vars body wheres = + HsFunBind [HsMatch srcloc (HsIdent name) (funargs vars) body wheres] + + +generateCode :: FilePath -> String -> HesqlModule -> IO HsModule +generateCode fn db (HesqlModule modName decls) = do + conn <- connectPostgreSQL db + mapM_ (verifySql conn . declSQL) decls' + return $ HsModule srcloc (Module modName) Nothing imports hsDecls + where imports = [HsImportDecl srcloc (Module "Database.HDBC") + False Nothing Nothing] + hsDecls = [dataType, initFun decls'] ++ map declFun decls' + dataType = HsDataDecl srcloc [] stmtRec [] + [HsRecDecl srcloc stmtRec recFields] [] + mkRecField decl = ([HsIdent $ stmtRecName decl], HsBangedTy (HsTyCon $ UnQual $ HsIdent"Statement")) + recFields = map mkRecField decls + decls' = map updateDeclSql decls + + +updateDeclSql decl = decl { declSQL = substituteVarsSql (declVars decl) (declSQL decl) } + +hsapp fun = HsApp (HsVar $ UnQual $ HsSymbol fun) +hsapps fun exps = foldl HsApp (HsVar $ UnQual $ HsSymbol fun) exps +hsvar v = HsVar $ UnQual $ HsSymbol v + +stmtRecName decl = "stmt_" ++ declName decl + +initFun decls = + hsSimpleFun "init" ["conn"] body [] + where body = HsUnGuardedRhs $ HsDo (mkStmts ++ [returnRec]) + mkStmts = map mkStmt decls + mkStmt decl = HsGenerator srcloc (HsPVar $ HsIdent $ declName decl) + (hsapps "prepare" [hsvar "conn", HsLit $ HsString sqlText]) + where sqlText = show $ declSQL decl + returnRec = HsQualifier $ hsapp "return" $ HsRecConstr (UnQual $ stmtRec) fields + fields = map mkField decls + mkField decl = HsFieldUpdate + (UnQual $ HsIdent $ stmtRecName decl) + (HsVar $ UnQual $ HsIdent $ declName decl) + + +declFun decl = -- TODO declLOC + hsSimpleFun (declName decl) ("h":declVars decl) body (stmtDef : maybeTupleFun) + where body = HsUnGuardedRhs $ HsDo (bindAndExecute:result) + bindAndExecute = HsQualifier $ hsapps "execute" [stmt, valList] + selectFlag = isSelect $ declSQL decl + result + | selectFlag = [resultStmt (selectOpts $ declSQL decl) stmt] + | otherwise = [] + maybeTupleFun + | selectFlag = [tupleFun $ selectColumnLength $ selectColumns $ declSQL decl] + | otherwise = [] + stmt = HsVar $ UnQual $ HsSymbol "stmt" + valList = HsList $ map mkSqlVal $ placeHoldersSql $ declSQL decl + mkSqlVal v = hsapp "toSql" (hsvar v) + stmtDef = HsPatBind srcloc (HsPVar $ HsIdent "stmt") + (HsUnGuardedRhs $ HsApp (HsVar $ UnQual $ HsIdent $ stmtRecName decl) (hsvar "h")) + [] + +resultStmt opts stmt = HsQualifier $ hsapps "fmap" [HsParen (hsapp "fmap" (hsvar "toTuple")), HsParen (hsapp (prefix++suffix) stmt)] + where suffix + | opts == [Strict] = "'" + | otherwise = "" + prefix + | ReturnMaybe `elem` opts = "fetchRow" + | otherwise = "fetchAllRows" + + + + +tupleFun n = HsFunBind [ + HsMatch srcloc (HsIdent "toTuple") [HsPList $ map HsPVar lvars] + (HsUnGuardedRhs (HsTuple (map convVar lvars))) [] + , HsMatch srcloc (HsIdent "toTuple") [HsPWildCard] + (HsUnGuardedRhs (hsapp "error" $ HsLit $ HsString "hesql internal error")) + [] + ] + + where lvars = map lvar [1..n] + lvar i = HsIdent $ "v" ++ show i + convVar v = hsapp "fromSql" (HsVar (UnQual v)) + +placeHoldersSql (SELECT _ cols from wh ord grp) = + maybe [] placeHoldersExp wh + +placeHoldersSql (INSERT _ _ vals) = + concatMap placeHoldersExp vals + +placeHoldersSql (UPDATE _ updates wh) = + concatMap (placeHoldersExp . snd) updates ++ + maybe [] placeHoldersExp wh + +placeHoldersExp (SqlPlaceHolder ph) = [ph] +placeHoldersExp (SqlInfixApp e1 _ e2) = placeHoldersExp e1 ++ placeHoldersExp e2 +placeHoldersExp (SqlColumn _) = [] +placeHoldersExp (SqlFunApp n args) = concatMap placeHoldersExp args +placeHoldersExp (SqlLiteral _) = [] +placeHoldersExp (SqlNot e) = placeHoldersExp e + + +substituteVarsExp vars (SqlInfixApp e1 op e2) = + SqlInfixApp e1' op e2' + where e1' = substituteVarsExp vars e1 + e2' = substituteVarsExp vars e2 + +substituteVarsExp _ sql@(SqlPlaceHolder _) = sql +substituteVarsExp _ sql@(SqlLiteral _) = sql +substituteVarsExp vars sql@(SqlColumn col) + | col `elem` vars = SqlPlaceHolder col + | otherwise = sql +substituteVarsExp vars (SqlNot e) = SqlNot (substituteVarsExp vars e) + +substituteVarsExp vars (SqlFunApp n args) = + SqlFunApp n (map (substituteVarsExp vars) args) + +substituteVarsSql vars (SELECT opt cols from wh ord grp) = + SELECT opt cols from + wh' + ord grp + where wh' :: Maybe SqlExp + wh' = fmap (substituteVarsExp vars) wh + +substituteVarsSql vars (INSERT tab spec vals) = + INSERT tab spec $ map (substituteVarsExp vars) vals + +substituteVarsSql vars (UPDATE tab updates wh) = + UPDATE tab updates' $ fmap (substituteVarsExp vars) wh + where updates' = map (mapSnd $ substituteVarsExp vars) updates + + + +mapSnd f (a, b) = (a, f b) + + +selectColumnLength (ExplicitColumns cols) = length cols + + diff --git a/HESQL/Verifier.hs b/HESQL/Verifier.hs new file mode 100644 --- /dev/null +++ b/HESQL/Verifier.hs @@ -0,0 +1,14 @@ +module HESQL.Verifier where + +import HESQL.Syntax +import Database.HDBC + +verifySql conn sql = + handleSqlError $ do + putStrLn $ "check " ++ sqlStr + prepare conn sqlStr >>= finish + where sqlStr = show sql + +-- TODO check column names in table. + + diff --git a/Makefile b/Makefile new file mode 100644 --- /dev/null +++ b/Makefile @@ -0,0 +1,17 @@ +all: .configured + ./Setup build + +clean: Setup + ./Setup clean + +.configured: hesql.cabal Setup + ./Setup configure + touch $@ + +Setup: Setup.hs + ghc --make Setup.hs + +install: all + ./Setup install + +.PHONY: all clean install diff --git a/README b/README new file mode 100644 --- /dev/null +++ b/README @@ -0,0 +1,95 @@ +hesql - Haskell's embedded SQL + +hesql is a preprocessor. It reads a file (module) with +SQL-like functions and translates it to Haskell source code. +It uses HDBC. + +The result of a select statement is automatically converted +to list of tuples. Also fromSql/toSql conversion are done. + +The current implementation is just a proof of concept with narrow limits. +It sticks to a subset of PostgreSQL's variant of SQL. Don't expect too +much, but please send me patches to improve hesql. + +An example is found under example/Account.hesql. It works with this +tables: + + +CREATE TABLE Account + (AccountID SERIAL PRIMARY KEY, + Login TEXT NOT NULL, + Password TEXT NOT NULL, + RealName TEXT, + Email TEXT NOT NULL, + LoggedIn BOOL DEFAULT FALSE NOT NULL, + Locked BOOL DEFAULT FALSE NOT NULL, + LastLogout TIMESTAMP, + LastRequest TimeStamp DEFAULT 'now' NOT NULL + ); + +CREATE UNIQUE INDEX AccountIdx ON Account(Lower(Login)); + +There are four select variants to use HDBC's strict/lazy fetch functions +and return a list or a maybe type. + + select: lazy, list of rows + select': strict, list of rows + select1: lazy, maybe row + select1': strict, maybe row + +For example: + +verifyLogin login' password' = + select1' Accountid, Login, RealName, Email from Account + where (password is null or password = md5(password')) and Lower(Login) = login' + and not Locked + +will generate code for a Haskell-Funktion with the type: + +verifyLogin :: Stmts -> String -> String -> Maybe (Int, String, String, String) + +(To be honest, the type is simplified by me. hesql won't write any type annotation.) + +Each module will have a function + +init :: Connection -> Stmts + +it prepares each statement for the later use. + + +TODO + - add a separate TODO file + - parse group by, order, having, column/table aliases, subselects + - verify table and column names + - resolve column names in SELECT * FROM ... + - fix command line argument parsing + - improve documentation + - make backup of old .hs-File + + +INSTALL + $ make + $ sudo make install + + +USAGE + $ createdb account + $ psql account + + # create the account table from above + + $ cd example/ + $ hesql Account.hesql dbname=account + $ less Account.hs + + +DEPENDENCIES: + + hesql depends on + - ghc + - postgresql + - HDBC with PostgreSQL backend + - haskell-src (to print the haskell code) + - parsec (for the SQL parser) + + diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMainWithHooks simpleUserHooks diff --git a/example/Account.hesql b/example/Account.hesql new file mode 100644 --- /dev/null +++ b/example/Account.hesql @@ -0,0 +1,27 @@ +module Account.DB where + +-- see README for the table definitions + +verifyLogin login' password' = + select1' Accountid, Login, RealName, Email from Account + where (password is null or password = md5(password')) and Lower(Login) = login' + and not Locked + +login accountid' = + update Account set LoggedIn = true where AccountID = accountid' + +logout acountid' = + update Account + set LoggedIn = false, + LastLogout = Now() + where AccountID = accountid' + + +createAccount login password email realname = + insert into Account (Login, Password, Email, RealName) values (login,md5(password),email,realname) + + +activeUsers = + select Login from Account + where LoggedIn and + now() - LastRequest < '00:05:00' diff --git a/hesql.cabal b/hesql.cabal new file mode 100644 --- /dev/null +++ b/hesql.cabal @@ -0,0 +1,21 @@ +Name: hesql +Version: 0.0 +Author: Christoph Bauer +Maintainer: Christoph Bauer +Cabal-Version: >= 1.2 +Build-Type: Simple +Synopsis: Haskell's embedded SQL +Category: Database +Extra-Source-Files: README, Makefile, Setup.hs, example/Account.hesql +Description: hesql rewrites SQL-function to Haskell/HDBC-functions +license: GPL +license-file: GPL + +Executable hesql + Main-is: HESQL.hs + Build-depends: base >= 2 && < 4, HDBC, HDBC-postgresql, haskell-src, + filepath, parsec + Extensions: FlexibleContexts + Ghc-Options: -funbox-strict-fields + Other-Modules: HESQL.Parser, HESQL.Translator, HESQL.Syntax, + HESQL.Verifier