root / htools / Ganeti / THH.hs @ c2e60027
History | View | Annotate | Download (28.8 kB)
1 |
{-# LANGUAGE TemplateHaskell #-} |
---|---|
2 |
|
3 |
{-| TemplateHaskell helper for HTools. |
4 |
|
5 |
As TemplateHaskell require that splices be defined in a separate |
6 |
module, we combine all the TemplateHaskell functionality that HTools |
7 |
needs in this module (except the one for unittests). |
8 |
|
9 |
-} |
10 |
|
11 |
{- |
12 |
|
13 |
Copyright (C) 2011, 2012 Google Inc. |
14 |
|
15 |
This program is free software; you can redistribute it and/or modify |
16 |
it under the terms of the GNU General Public License as published by |
17 |
the Free Software Foundation; either version 2 of the License, or |
18 |
(at your option) any later version. |
19 |
|
20 |
This program is distributed in the hope that it will be useful, but |
21 |
WITHOUT ANY WARRANTY; without even the implied warranty of |
22 |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
23 |
General Public License for more details. |
24 |
|
25 |
You should have received a copy of the GNU General Public License |
26 |
along with this program; if not, write to the Free Software |
27 |
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
28 |
02110-1301, USA. |
29 |
|
30 |
-} |
31 |
|
32 |
module Ganeti.THH ( declareSADT |
33 |
, declareIADT |
34 |
, makeJSONInstance |
35 |
, genOpID |
36 |
, genOpCode |
37 |
, genStrOfOp |
38 |
, genStrOfKey |
39 |
, genLuxiOp |
40 |
, Field |
41 |
, simpleField |
42 |
, defaultField |
43 |
, optionalField |
44 |
, renameField |
45 |
, containerField |
46 |
, customField |
47 |
, timeStampFields |
48 |
, uuidFields |
49 |
, serialFields |
50 |
, buildObject |
51 |
, buildObjectSerialisation |
52 |
, buildParam |
53 |
, Container |
54 |
) where |
55 |
|
56 |
import Control.Arrow |
57 |
import Control.Monad (liftM, liftM2) |
58 |
import Data.Char |
59 |
import Data.List |
60 |
import qualified Data.Map as M |
61 |
import Language.Haskell.TH |
62 |
|
63 |
import qualified Text.JSON as JSON |
64 |
|
65 |
import Ganeti.HTools.JSON |
66 |
|
67 |
-- * Exported types |
68 |
|
69 |
type Container = M.Map String |
70 |
|
71 |
-- | Serialised field data type. |
72 |
data Field = Field { fieldName :: String |
73 |
, fieldType :: Q Type |
74 |
, fieldRead :: Maybe (Q Exp) |
75 |
, fieldShow :: Maybe (Q Exp) |
76 |
, fieldDefault :: Maybe (Q Exp) |
77 |
, fieldConstr :: Maybe String |
78 |
, fieldIsContainer :: Bool |
79 |
, fieldIsOptional :: Bool |
80 |
} |
81 |
|
82 |
-- | Generates a simple field. |
83 |
simpleField :: String -> Q Type -> Field |
84 |
simpleField fname ftype = |
85 |
Field { fieldName = fname |
86 |
, fieldType = ftype |
87 |
, fieldRead = Nothing |
88 |
, fieldShow = Nothing |
89 |
, fieldDefault = Nothing |
90 |
, fieldConstr = Nothing |
91 |
, fieldIsContainer = False |
92 |
, fieldIsOptional = False |
93 |
} |
94 |
|
95 |
-- | Sets the renamed constructor field. |
96 |
renameField :: String -> Field -> Field |
97 |
renameField constrName field = field { fieldConstr = Just constrName } |
98 |
|
99 |
-- | Sets the default value on a field (makes it optional with a |
100 |
-- default value). |
101 |
defaultField :: Q Exp -> Field -> Field |
102 |
defaultField defval field = field { fieldDefault = Just defval } |
103 |
|
104 |
-- | Marks a field optional (turning its base type into a Maybe). |
105 |
optionalField :: Field -> Field |
106 |
optionalField field = field { fieldIsOptional = True } |
107 |
|
108 |
-- | Marks a field as a container. |
109 |
containerField :: Field -> Field |
110 |
containerField field = field { fieldIsContainer = True } |
111 |
|
112 |
-- | Sets custom functions on a field. |
113 |
customField :: Name -- ^ The name of the read function |
114 |
-> Name -- ^ The name of the show function |
115 |
-> Field -- ^ The original field |
116 |
-> Field -- ^ Updated field |
117 |
customField readfn showfn field = |
118 |
field { fieldRead = Just (varE readfn), fieldShow = Just (varE showfn) } |
119 |
|
120 |
fieldRecordName :: Field -> String |
121 |
fieldRecordName (Field { fieldName = name, fieldConstr = alias }) = |
122 |
maybe (camelCase name) id alias |
123 |
|
124 |
-- | Computes the preferred variable name to use for the value of this |
125 |
-- field. If the field has a specific constructor name, then we use a |
126 |
-- first-letter-lowercased version of that; otherwise, we simply use |
127 |
-- the field name. See also 'fieldRecordName'. |
128 |
fieldVariable :: Field -> String |
129 |
fieldVariable f = |
130 |
case (fieldConstr f) of |
131 |
Just name -> ensureLower name |
132 |
_ -> fieldName f |
133 |
|
134 |
actualFieldType :: Field -> Q Type |
135 |
actualFieldType f | fieldIsContainer f = [t| Container $t |] |
136 |
| fieldIsOptional f = [t| Maybe $t |] |
137 |
| otherwise = t |
138 |
where t = fieldType f |
139 |
|
140 |
checkNonOptDef :: (Monad m) => Field -> m () |
141 |
checkNonOptDef (Field { fieldIsOptional = True, fieldName = name }) = |
142 |
fail $ "Optional field " ++ name ++ " used in parameter declaration" |
143 |
checkNonOptDef (Field { fieldDefault = (Just _), fieldName = name }) = |
144 |
fail $ "Default field " ++ name ++ " used in parameter declaration" |
145 |
checkNonOptDef _ = return () |
146 |
|
147 |
loadFn :: Field -> Q Exp -> Q Exp |
148 |
loadFn (Field { fieldIsContainer = True }) expr = [| $expr >>= readContainer |] |
149 |
loadFn (Field { fieldRead = Just readfn }) expr = [| $expr >>= $readfn |] |
150 |
loadFn _ expr = expr |
151 |
|
152 |
|
153 |
-- * Common field declarations |
154 |
|
155 |
timeStampFields :: [Field] |
156 |
timeStampFields = |
157 |
[ defaultField [| 0::Double |] $ simpleField "ctime" [t| Double |] |
158 |
, defaultField [| 0::Double |] $ simpleField "mtime" [t| Double |] |
159 |
] |
160 |
|
161 |
serialFields :: [Field] |
162 |
serialFields = |
163 |
[ renameField "Serial" $ simpleField "serial_no" [t| Int |] ] |
164 |
|
165 |
uuidFields :: [Field] |
166 |
uuidFields = [ simpleField "uuid" [t| String |] ] |
167 |
|
168 |
-- * Helper functions |
169 |
|
170 |
-- | Ensure first letter is lowercase. |
171 |
-- |
172 |
-- Used to convert type name to function prefix, e.g. in @data Aa -> |
173 |
-- aaToRaw@. |
174 |
ensureLower :: String -> String |
175 |
ensureLower [] = [] |
176 |
ensureLower (x:xs) = toLower x:xs |
177 |
|
178 |
-- | Ensure first letter is uppercase. |
179 |
-- |
180 |
-- Used to convert constructor name to component |
181 |
ensureUpper :: String -> String |
182 |
ensureUpper [] = [] |
183 |
ensureUpper (x:xs) = toUpper x:xs |
184 |
|
185 |
-- | Helper for quoted expressions. |
186 |
varNameE :: String -> Q Exp |
187 |
varNameE = varE . mkName |
188 |
|
189 |
-- | showJSON as an expression, for reuse. |
190 |
showJSONE :: Q Exp |
191 |
showJSONE = varNameE "showJSON" |
192 |
|
193 |
-- | ToRaw function name. |
194 |
toRawName :: String -> Name |
195 |
toRawName = mkName . (++ "ToRaw") . ensureLower |
196 |
|
197 |
-- | FromRaw function name. |
198 |
fromRawName :: String -> Name |
199 |
fromRawName = mkName . (++ "FromRaw") . ensureLower |
200 |
|
201 |
-- | Converts a name to it's varE/litE representations. |
202 |
-- |
203 |
reprE :: Either String Name -> Q Exp |
204 |
reprE = either stringE varE |
205 |
|
206 |
-- | Smarter function application. |
207 |
-- |
208 |
-- This does simply f x, except that if is 'id', it will skip it, in |
209 |
-- order to generate more readable code when using -ddump-splices. |
210 |
appFn :: Exp -> Exp -> Exp |
211 |
appFn f x | f == VarE 'id = x |
212 |
| otherwise = AppE f x |
213 |
|
214 |
-- | Container loader |
215 |
readContainer :: (Monad m, JSON.JSON a) => |
216 |
JSON.JSObject JSON.JSValue -> m (Container a) |
217 |
readContainer obj = do |
218 |
let kjvlist = JSON.fromJSObject obj |
219 |
kalist <- mapM (\(k, v) -> fromKeyValue k v >>= \a -> return (k, a)) kjvlist |
220 |
return $ M.fromList kalist |
221 |
|
222 |
-- | Container dumper |
223 |
showContainer :: (JSON.JSON a) => Container a -> JSON.JSValue |
224 |
showContainer = JSON.makeObj . map (second JSON.showJSON) . M.toList |
225 |
|
226 |
-- * Template code for simple raw type-equivalent ADTs |
227 |
|
228 |
-- | Generates a data type declaration. |
229 |
-- |
230 |
-- The type will have a fixed list of instances. |
231 |
strADTDecl :: Name -> [String] -> Dec |
232 |
strADTDecl name constructors = |
233 |
DataD [] name [] |
234 |
(map (flip NormalC [] . mkName) constructors) |
235 |
[''Show, ''Read, ''Eq, ''Enum, ''Bounded, ''Ord] |
236 |
|
237 |
-- | Generates a toRaw function. |
238 |
-- |
239 |
-- This generates a simple function of the form: |
240 |
-- |
241 |
-- @ |
242 |
-- nameToRaw :: Name -> /traw/ |
243 |
-- nameToRaw Cons1 = var1 |
244 |
-- nameToRaw Cons2 = \"value2\" |
245 |
-- @ |
246 |
genToRaw :: Name -> Name -> Name -> [(String, Either String Name)] -> Q [Dec] |
247 |
genToRaw traw fname tname constructors = do |
248 |
let sigt = AppT (AppT ArrowT (ConT tname)) (ConT traw) |
249 |
-- the body clauses, matching on the constructor and returning the |
250 |
-- raw value |
251 |
clauses <- mapM (\(c, v) -> clause [recP (mkName c) []] |
252 |
(normalB (reprE v)) []) constructors |
253 |
return [SigD fname sigt, FunD fname clauses] |
254 |
|
255 |
-- | Generates a fromRaw function. |
256 |
-- |
257 |
-- The function generated is monadic and can fail parsing the |
258 |
-- raw value. It is of the form: |
259 |
-- |
260 |
-- @ |
261 |
-- nameFromRaw :: (Monad m) => /traw/ -> m Name |
262 |
-- nameFromRaw s | s == var1 = Cons1 |
263 |
-- | s == \"value2\" = Cons2 |
264 |
-- | otherwise = fail /.../ |
265 |
-- @ |
266 |
genFromRaw :: Name -> Name -> Name -> [(String, Name)] -> Q [Dec] |
267 |
genFromRaw traw fname tname constructors = do |
268 |
-- signature of form (Monad m) => String -> m $name |
269 |
sigt <- [t| (Monad m) => $(conT traw) -> m $(conT tname) |] |
270 |
-- clauses for a guarded pattern |
271 |
let varp = mkName "s" |
272 |
varpe = varE varp |
273 |
clauses <- mapM (\(c, v) -> do |
274 |
-- the clause match condition |
275 |
g <- normalG [| $varpe == $(varE v) |] |
276 |
-- the clause result |
277 |
r <- [| return $(conE (mkName c)) |] |
278 |
return (g, r)) constructors |
279 |
-- the otherwise clause (fallback) |
280 |
oth_clause <- do |
281 |
g <- normalG [| otherwise |] |
282 |
r <- [|fail ("Invalid string value for type " ++ |
283 |
$(litE (stringL (nameBase tname))) ++ ": " ++ show $varpe) |] |
284 |
return (g, r) |
285 |
let fun = FunD fname [Clause [VarP varp] |
286 |
(GuardedB (clauses++[oth_clause])) []] |
287 |
return [SigD fname sigt, fun] |
288 |
|
289 |
-- | Generates a data type from a given raw format. |
290 |
-- |
291 |
-- The format is expected to multiline. The first line contains the |
292 |
-- type name, and the rest of the lines must contain two words: the |
293 |
-- constructor name and then the string representation of the |
294 |
-- respective constructor. |
295 |
-- |
296 |
-- The function will generate the data type declaration, and then two |
297 |
-- functions: |
298 |
-- |
299 |
-- * /name/ToRaw, which converts the type to a raw type |
300 |
-- |
301 |
-- * /name/FromRaw, which (monadically) converts from a raw type to the type |
302 |
-- |
303 |
-- Note that this is basically just a custom show/read instance, |
304 |
-- nothing else. |
305 |
declareADT :: Name -> String -> [(String, Name)] -> Q [Dec] |
306 |
declareADT traw sname cons = do |
307 |
let name = mkName sname |
308 |
ddecl = strADTDecl name (map fst cons) |
309 |
-- process cons in the format expected by genToRaw |
310 |
cons' = map (\(a, b) -> (a, Right b)) cons |
311 |
toraw <- genToRaw traw (toRawName sname) name cons' |
312 |
fromraw <- genFromRaw traw (fromRawName sname) name cons |
313 |
return $ ddecl:toraw ++ fromraw |
314 |
|
315 |
declareIADT :: String -> [(String, Name)] -> Q [Dec] |
316 |
declareIADT = declareADT ''Int |
317 |
|
318 |
declareSADT :: String -> [(String, Name)] -> Q [Dec] |
319 |
declareSADT = declareADT ''String |
320 |
|
321 |
-- | Creates the showJSON member of a JSON instance declaration. |
322 |
-- |
323 |
-- This will create what is the equivalent of: |
324 |
-- |
325 |
-- @ |
326 |
-- showJSON = showJSON . /name/ToRaw |
327 |
-- @ |
328 |
-- |
329 |
-- in an instance JSON /name/ declaration |
330 |
genShowJSON :: String -> Q Dec |
331 |
genShowJSON name = do |
332 |
body <- [| JSON.showJSON . $(varE (toRawName name)) |] |
333 |
return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []] |
334 |
|
335 |
-- | Creates the readJSON member of a JSON instance declaration. |
336 |
-- |
337 |
-- This will create what is the equivalent of: |
338 |
-- |
339 |
-- @ |
340 |
-- readJSON s = case readJSON s of |
341 |
-- Ok s' -> /name/FromRaw s' |
342 |
-- Error e -> Error /description/ |
343 |
-- @ |
344 |
-- |
345 |
-- in an instance JSON /name/ declaration |
346 |
genReadJSON :: String -> Q Dec |
347 |
genReadJSON name = do |
348 |
let s = mkName "s" |
349 |
body <- [| case JSON.readJSON $(varE s) of |
350 |
JSON.Ok s' -> $(varE (fromRawName name)) s' |
351 |
JSON.Error e -> |
352 |
JSON.Error $ "Can't parse raw value for type " ++ |
353 |
$(stringE name) ++ ": " ++ e ++ " from " ++ |
354 |
show $(varE s) |
355 |
|] |
356 |
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []] |
357 |
|
358 |
-- | Generates a JSON instance for a given type. |
359 |
-- |
360 |
-- This assumes that the /name/ToRaw and /name/FromRaw functions |
361 |
-- have been defined as by the 'declareSADT' function. |
362 |
makeJSONInstance :: Name -> Q [Dec] |
363 |
makeJSONInstance name = do |
364 |
let base = nameBase name |
365 |
showJ <- genShowJSON base |
366 |
readJ <- genReadJSON base |
367 |
return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) [readJ,showJ]] |
368 |
|
369 |
-- * Template code for opcodes |
370 |
|
371 |
-- | Transforms a CamelCase string into an_underscore_based_one. |
372 |
deCamelCase :: String -> String |
373 |
deCamelCase = |
374 |
intercalate "_" . map (map toUpper) . groupBy (\_ b -> not $ isUpper b) |
375 |
|
376 |
-- | Transform an underscore_name into a CamelCase one. |
377 |
camelCase :: String -> String |
378 |
camelCase = concatMap (ensureUpper . drop 1) . |
379 |
groupBy (\_ b -> b /= '_') . ('_':) |
380 |
|
381 |
-- | Computes the name of a given constructor. |
382 |
constructorName :: Con -> Q Name |
383 |
constructorName (NormalC name _) = return name |
384 |
constructorName (RecC name _) = return name |
385 |
constructorName x = fail $ "Unhandled constructor " ++ show x |
386 |
|
387 |
-- | Builds the generic constructor-to-string function. |
388 |
-- |
389 |
-- This generates a simple function of the following form: |
390 |
-- |
391 |
-- @ |
392 |
-- fname (ConStructorOne {}) = trans_fun("ConStructorOne") |
393 |
-- fname (ConStructorTwo {}) = trans_fun("ConStructorTwo") |
394 |
-- @ |
395 |
-- |
396 |
-- This builds a custom list of name/string pairs and then uses |
397 |
-- 'genToRaw' to actually generate the function |
398 |
genConstrToStr :: (String -> String) -> Name -> String -> Q [Dec] |
399 |
genConstrToStr trans_fun name fname = do |
400 |
TyConI (DataD _ _ _ cons _) <- reify name |
401 |
cnames <- mapM (liftM nameBase . constructorName) cons |
402 |
let svalues = map (Left . trans_fun) cnames |
403 |
genToRaw ''String (mkName fname) name $ zip cnames svalues |
404 |
|
405 |
-- | Constructor-to-string for OpCode. |
406 |
genOpID :: Name -> String -> Q [Dec] |
407 |
genOpID = genConstrToStr deCamelCase |
408 |
|
409 |
-- | OpCode parameter (field) type. |
410 |
type OpParam = (String, Q Type, Q Exp) |
411 |
|
412 |
-- | Generates the OpCode data type. |
413 |
-- |
414 |
-- This takes an opcode logical definition, and builds both the |
415 |
-- datatype and the JSON serialisation out of it. We can't use a |
416 |
-- generic serialisation since we need to be compatible with Ganeti's |
417 |
-- own, so we have a few quirks to work around. |
418 |
genOpCode :: String -- ^ Type name to use |
419 |
-> [(String, [Field])] -- ^ Constructor name and parameters |
420 |
-> Q [Dec] |
421 |
genOpCode name cons = do |
422 |
decl_d <- mapM (\(cname, fields) -> do |
423 |
-- we only need the type of the field, without Q |
424 |
fields' <- mapM actualFieldType fields |
425 |
let fields'' = zip (repeat NotStrict) fields' |
426 |
return $ NormalC (mkName cname) fields'') |
427 |
cons |
428 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq] |
429 |
|
430 |
(savesig, savefn) <- genSaveOpCode cons |
431 |
(loadsig, loadfn) <- genLoadOpCode cons |
432 |
return [declD, loadsig, loadfn, savesig, savefn] |
433 |
|
434 |
-- | Checks whether a given parameter is options. |
435 |
-- |
436 |
-- This requires that it's a 'Maybe'. |
437 |
isOptional :: Type -> Bool |
438 |
isOptional (AppT (ConT dt) _) | dt == ''Maybe = True |
439 |
isOptional _ = False |
440 |
|
441 |
-- | Generates the \"save\" clause for an entire opcode constructor. |
442 |
-- |
443 |
-- This matches the opcode with variables named the same as the |
444 |
-- constructor fields (just so that the spliced in code looks nicer), |
445 |
-- and passes those name plus the parameter definition to 'saveObjectField'. |
446 |
saveConstructor :: String -- ^ The constructor name |
447 |
-> [Field] -- ^ The parameter definitions for this |
448 |
-- constructor |
449 |
-> Q Clause -- ^ Resulting clause |
450 |
saveConstructor sname fields = do |
451 |
let cname = mkName sname |
452 |
let fnames = map (mkName . fieldVariable) fields |
453 |
let pat = conP cname (map varP fnames) |
454 |
let felems = map (uncurry saveObjectField) (zip fnames fields) |
455 |
-- now build the OP_ID serialisation |
456 |
opid = [| [( $(stringE "OP_ID"), |
457 |
JSON.showJSON $(stringE . deCamelCase $ sname) )] |] |
458 |
flist = listE (opid:felems) |
459 |
-- and finally convert all this to a json object |
460 |
flist' = [| $(varNameE "makeObj") (concat $flist) |] |
461 |
clause [pat] (normalB flist') [] |
462 |
|
463 |
-- | Generates the main save opcode function. |
464 |
-- |
465 |
-- This builds a per-constructor match clause that contains the |
466 |
-- respective constructor-serialisation code. |
467 |
genSaveOpCode :: [(String, [Field])] -> Q (Dec, Dec) |
468 |
genSaveOpCode opdefs = do |
469 |
cclauses <- mapM (uncurry saveConstructor) opdefs |
470 |
let fname = mkName "saveOpCode" |
471 |
sigt <- [t| $(conT (mkName "OpCode")) -> JSON.JSValue |] |
472 |
return $ (SigD fname sigt, FunD fname cclauses) |
473 |
|
474 |
loadConstructor :: String -> [Field] -> Q Exp |
475 |
loadConstructor sname fields = do |
476 |
let name = mkName sname |
477 |
fbinds <- mapM loadObjectField fields |
478 |
let (fnames, fstmts) = unzip fbinds |
479 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
480 |
fstmts' = fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
481 |
return $ DoE fstmts' |
482 |
|
483 |
genLoadOpCode :: [(String, [Field])] -> Q (Dec, Dec) |
484 |
genLoadOpCode opdefs = do |
485 |
let fname = mkName "loadOpCode" |
486 |
arg1 = mkName "v" |
487 |
objname = mkName "o" |
488 |
opid = mkName "op_id" |
489 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
490 |
(JSON.readJSON $(varE arg1)) |] |
491 |
st2 <- bindS (varP opid) [| $(varNameE "fromObj") |
492 |
$(varE objname) $(stringE "OP_ID") |] |
493 |
-- the match results (per-constructor blocks) |
494 |
mexps <- mapM (uncurry loadConstructor) opdefs |
495 |
fails <- [| fail $ "Unknown opcode " ++ $(varE opid) |] |
496 |
let mpats = map (\(me, c) -> |
497 |
let mp = LitP . StringL . deCamelCase . fst $ c |
498 |
in Match mp (NormalB me) [] |
499 |
) $ zip mexps opdefs |
500 |
defmatch = Match WildP (NormalB fails) [] |
501 |
cst = NoBindS $ CaseE (VarE opid) $ mpats++[defmatch] |
502 |
body = DoE [st1, st2, cst] |
503 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT (mkName "OpCode")) |] |
504 |
return $ (SigD fname sigt, FunD fname [Clause [VarP arg1] (NormalB body) []]) |
505 |
|
506 |
-- * Template code for luxi |
507 |
|
508 |
-- | Constructor-to-string for LuxiOp. |
509 |
genStrOfOp :: Name -> String -> Q [Dec] |
510 |
genStrOfOp = genConstrToStr id |
511 |
|
512 |
-- | Constructor-to-string for MsgKeys. |
513 |
genStrOfKey :: Name -> String -> Q [Dec] |
514 |
genStrOfKey = genConstrToStr ensureLower |
515 |
|
516 |
-- | LuxiOp parameter type. |
517 |
type LuxiParam = (String, Q Type, Q Exp) |
518 |
|
519 |
-- | Generates the LuxiOp data type. |
520 |
-- |
521 |
-- This takes a Luxi operation definition and builds both the |
522 |
-- datatype and the function trnasforming the arguments to JSON. |
523 |
-- We can't use anything less generic, because the way different |
524 |
-- operations are serialized differs on both parameter- and top-level. |
525 |
-- |
526 |
-- There are three things to be defined for each parameter: |
527 |
-- |
528 |
-- * name |
529 |
-- |
530 |
-- * type |
531 |
-- |
532 |
-- * operation; this is the operation performed on the parameter before |
533 |
-- serialization |
534 |
-- |
535 |
genLuxiOp :: String -> [(String, [LuxiParam])] -> Q [Dec] |
536 |
genLuxiOp name cons = do |
537 |
decl_d <- mapM (\(cname, fields) -> do |
538 |
fields' <- mapM (\(_, qt, _) -> |
539 |
qt >>= \t -> return (NotStrict, t)) |
540 |
fields |
541 |
return $ NormalC (mkName cname) fields') |
542 |
cons |
543 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq] |
544 |
(savesig, savefn) <- genSaveLuxiOp cons |
545 |
req_defs <- declareSADT "LuxiReq" . |
546 |
map (\(str, _) -> ("Req" ++ str, mkName ("luxiReq" ++ str))) $ |
547 |
cons |
548 |
return $ [declD, savesig, savefn] ++ req_defs |
549 |
|
550 |
-- | Generates the \"save\" expression for a single luxi parameter. |
551 |
saveLuxiField :: Name -> LuxiParam -> Q Exp |
552 |
saveLuxiField fvar (_, qt, fn) = |
553 |
[| JSON.showJSON ( $(liftM2 appFn fn $ varE fvar) ) |] |
554 |
|
555 |
-- | Generates the \"save\" clause for entire LuxiOp constructor. |
556 |
saveLuxiConstructor :: (String, [LuxiParam]) -> Q Clause |
557 |
saveLuxiConstructor (sname, fields) = do |
558 |
let cname = mkName sname |
559 |
fnames = map (\(nm, _, _) -> mkName nm) fields |
560 |
pat = conP cname (map varP fnames) |
561 |
flist = map (uncurry saveLuxiField) (zip fnames fields) |
562 |
finval = if null flist |
563 |
then [| JSON.showJSON () |] |
564 |
else [| JSON.showJSON $(listE flist) |] |
565 |
clause [pat] (normalB finval) [] |
566 |
|
567 |
-- | Generates the main save LuxiOp function. |
568 |
genSaveLuxiOp :: [(String, [LuxiParam])]-> Q (Dec, Dec) |
569 |
genSaveLuxiOp opdefs = do |
570 |
sigt <- [t| $(conT (mkName "LuxiOp")) -> JSON.JSValue |] |
571 |
let fname = mkName "opToArgs" |
572 |
cclauses <- mapM saveLuxiConstructor opdefs |
573 |
return $ (SigD fname sigt, FunD fname cclauses) |
574 |
|
575 |
-- * "Objects" functionality |
576 |
|
577 |
-- | Extract the field's declaration from a Field structure. |
578 |
fieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
579 |
fieldTypeInfo field_pfx fd = do |
580 |
t <- actualFieldType fd |
581 |
let n = mkName . (field_pfx ++) . fieldRecordName $ fd |
582 |
return (n, NotStrict, t) |
583 |
|
584 |
-- | Build an object declaration. |
585 |
buildObject :: String -> String -> [Field] -> Q [Dec] |
586 |
buildObject sname field_pfx fields = do |
587 |
let name = mkName sname |
588 |
fields_d <- mapM (fieldTypeInfo field_pfx) fields |
589 |
let decl_d = RecC name fields_d |
590 |
let declD = DataD [] name [] [decl_d] [''Show, ''Read, ''Eq] |
591 |
ser_decls <- buildObjectSerialisation sname fields |
592 |
return $ declD:ser_decls |
593 |
|
594 |
buildObjectSerialisation :: String -> [Field] -> Q [Dec] |
595 |
buildObjectSerialisation sname fields = do |
596 |
let name = mkName sname |
597 |
savedecls <- genSaveObject saveObjectField sname fields |
598 |
(loadsig, loadfn) <- genLoadObject loadObjectField sname fields |
599 |
shjson <- objectShowJSON sname |
600 |
rdjson <- objectReadJSON sname |
601 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
602 |
[rdjson, shjson] |
603 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
604 |
|
605 |
genSaveObject :: (Name -> Field -> Q Exp) |
606 |
-> String -> [Field] -> Q [Dec] |
607 |
genSaveObject save_fn sname fields = do |
608 |
let name = mkName sname |
609 |
let fnames = map (mkName . fieldVariable) fields |
610 |
let pat = conP name (map varP fnames) |
611 |
let tdname = mkName ("toDict" ++ sname) |
612 |
tdsigt <- [t| $(conT name) -> [(String, JSON.JSValue)] |] |
613 |
|
614 |
let felems = map (uncurry save_fn) (zip fnames fields) |
615 |
flist = listE felems |
616 |
-- and finally convert all this to a json object |
617 |
tdlist = [| concat $flist |] |
618 |
iname = mkName "i" |
619 |
tclause <- clause [pat] (normalB tdlist) [] |
620 |
cclause <- [| $(varNameE "makeObj") . $(varE tdname) |] |
621 |
let fname = mkName ("save" ++ sname) |
622 |
sigt <- [t| $(conT name) -> JSON.JSValue |] |
623 |
return [SigD tdname tdsigt, FunD tdname [tclause], |
624 |
SigD fname sigt, ValD (VarP fname) (NormalB cclause) []] |
625 |
|
626 |
saveObjectField :: Name -> Field -> Q Exp |
627 |
saveObjectField fvar field |
628 |
| isContainer = [| [( $nameE , JSON.showJSON . showContainer $ $fvarE)] |] |
629 |
| fisOptional = [| case $(varE fvar) of |
630 |
Nothing -> [] |
631 |
Just v -> [( $nameE, JSON.showJSON v)] |
632 |
|] |
633 |
| otherwise = case fieldShow field of |
634 |
Nothing -> [| [( $nameE, JSON.showJSON $fvarE)] |] |
635 |
Just fn -> [| [( $nameE, JSON.showJSON . $fn $ $fvarE)] |] |
636 |
where isContainer = fieldIsContainer field |
637 |
fisOptional = fieldIsOptional field |
638 |
nameE = stringE (fieldName field) |
639 |
fvarE = varE fvar |
640 |
|
641 |
objectShowJSON :: String -> Q Dec |
642 |
objectShowJSON name = do |
643 |
body <- [| JSON.showJSON . $(varE . mkName $ "save" ++ name) |] |
644 |
return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []] |
645 |
|
646 |
genLoadObject :: (Field -> Q (Name, Stmt)) |
647 |
-> String -> [Field] -> Q (Dec, Dec) |
648 |
genLoadObject load_fn sname fields = do |
649 |
let name = mkName sname |
650 |
funname = mkName $ "load" ++ sname |
651 |
arg1 = mkName "v" |
652 |
objname = mkName "o" |
653 |
opid = mkName "op_id" |
654 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
655 |
(JSON.readJSON $(varE arg1)) |] |
656 |
fbinds <- mapM load_fn fields |
657 |
let (fnames, fstmts) = unzip fbinds |
658 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
659 |
fstmts' = st1:fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
660 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT name) |] |
661 |
return $ (SigD funname sigt, |
662 |
FunD funname [Clause [VarP arg1] (NormalB (DoE fstmts')) []]) |
663 |
|
664 |
loadObjectField :: Field -> Q (Name, Stmt) |
665 |
loadObjectField field = do |
666 |
let name = fieldVariable field |
667 |
fvar = mkName name |
668 |
-- these are used in all patterns below |
669 |
let objvar = varNameE "o" |
670 |
objfield = stringE (fieldName field) |
671 |
loadexp = |
672 |
if fieldIsOptional field |
673 |
then [| $(varNameE "maybeFromObj") $objvar $objfield |] |
674 |
else case fieldDefault field of |
675 |
Just defv -> |
676 |
[| $(varNameE "fromObjWithDefault") $objvar |
677 |
$objfield $defv |] |
678 |
Nothing -> [| $(varNameE "fromObj") $objvar $objfield |] |
679 |
bexp <- loadFn field loadexp |
680 |
|
681 |
return (fvar, BindS (VarP fvar) bexp) |
682 |
|
683 |
objectReadJSON :: String -> Q Dec |
684 |
objectReadJSON name = do |
685 |
let s = mkName "s" |
686 |
body <- [| case JSON.readJSON $(varE s) of |
687 |
JSON.Ok s' -> $(varE .mkName $ "load" ++ name) s' |
688 |
JSON.Error e -> |
689 |
JSON.Error $ "Can't parse value for type " ++ |
690 |
$(stringE name) ++ ": " ++ e |
691 |
|] |
692 |
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []] |
693 |
|
694 |
-- * Inheritable parameter tables implementation |
695 |
|
696 |
-- | Compute parameter type names. |
697 |
paramTypeNames :: String -> (String, String) |
698 |
paramTypeNames root = ("Filled" ++ root ++ "Params", |
699 |
"Partial" ++ root ++ "Params") |
700 |
|
701 |
-- | Compute information about the type of a parameter field. |
702 |
paramFieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
703 |
paramFieldTypeInfo field_pfx fd = do |
704 |
t <- actualFieldType fd |
705 |
let n = mkName . (++ "P") . (field_pfx ++) . |
706 |
fieldRecordName $ fd |
707 |
return (n, NotStrict, AppT (ConT ''Maybe) t) |
708 |
|
709 |
-- | Build a parameter declaration. |
710 |
-- |
711 |
-- This function builds two different data structures: a /filled/ one, |
712 |
-- in which all fields are required, and a /partial/ one, in which all |
713 |
-- fields are optional. Due to the current record syntax issues, the |
714 |
-- fields need to be named differrently for the two structures, so the |
715 |
-- partial ones get a /P/ suffix. |
716 |
buildParam :: String -> String -> [Field] -> Q [Dec] |
717 |
buildParam sname field_pfx fields = do |
718 |
let (sname_f, sname_p) = paramTypeNames sname |
719 |
name_f = mkName sname_f |
720 |
name_p = mkName sname_p |
721 |
fields_f <- mapM (fieldTypeInfo field_pfx) fields |
722 |
fields_p <- mapM (paramFieldTypeInfo field_pfx) fields |
723 |
let decl_f = RecC name_f fields_f |
724 |
decl_p = RecC name_p fields_p |
725 |
let declF = DataD [] name_f [] [decl_f] [''Show, ''Read, ''Eq] |
726 |
declP = DataD [] name_p [] [decl_p] [''Show, ''Read, ''Eq] |
727 |
ser_decls_f <- buildObjectSerialisation sname_f fields |
728 |
ser_decls_p <- buildPParamSerialisation sname_p fields |
729 |
fill_decls <- fillParam sname field_pfx fields |
730 |
return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls |
731 |
|
732 |
buildPParamSerialisation :: String -> [Field] -> Q [Dec] |
733 |
buildPParamSerialisation sname fields = do |
734 |
let name = mkName sname |
735 |
savedecls <- genSaveObject savePParamField sname fields |
736 |
(loadsig, loadfn) <- genLoadObject loadPParamField sname fields |
737 |
shjson <- objectShowJSON sname |
738 |
rdjson <- objectReadJSON sname |
739 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
740 |
[rdjson, shjson] |
741 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
742 |
|
743 |
savePParamField :: Name -> Field -> Q Exp |
744 |
savePParamField fvar field = do |
745 |
checkNonOptDef field |
746 |
let actualVal = mkName "v" |
747 |
normalexpr <- saveObjectField actualVal field |
748 |
-- we have to construct the block here manually, because we can't |
749 |
-- splice-in-splice |
750 |
return $ CaseE (VarE fvar) [ Match (ConP 'Nothing []) |
751 |
(NormalB (ConE '[])) [] |
752 |
, Match (ConP 'Just [VarP actualVal]) |
753 |
(NormalB normalexpr) [] |
754 |
] |
755 |
loadPParamField :: Field -> Q (Name, Stmt) |
756 |
loadPParamField field = do |
757 |
checkNonOptDef field |
758 |
let name = fieldName field |
759 |
fvar = mkName name |
760 |
-- these are used in all patterns below |
761 |
let objvar = varNameE "o" |
762 |
objfield = stringE name |
763 |
loadexp = [| $(varNameE "maybeFromObj") $objvar $objfield |] |
764 |
bexp <- loadFn field loadexp |
765 |
return (fvar, BindS (VarP fvar) bexp) |
766 |
|
767 |
-- | Builds a simple declaration of type @n_x = fromMaybe f_x p_x@. |
768 |
buildFromMaybe :: String -> Q Dec |
769 |
buildFromMaybe fname = |
770 |
valD (varP (mkName $ "n_" ++ fname)) |
771 |
(normalB [| $(varNameE "fromMaybe") |
772 |
$(varNameE $ "f_" ++ fname) |
773 |
$(varNameE $ "p_" ++ fname) |]) [] |
774 |
|
775 |
fillParam :: String -> String -> [Field] -> Q [Dec] |
776 |
fillParam sname field_pfx fields = do |
777 |
let fnames = map (\fd -> field_pfx ++ fieldRecordName fd) fields |
778 |
(sname_f, sname_p) = paramTypeNames sname |
779 |
oname_f = "fobj" |
780 |
oname_p = "pobj" |
781 |
name_f = mkName sname_f |
782 |
name_p = mkName sname_p |
783 |
fun_name = mkName $ "fill" ++ sname ++ "Params" |
784 |
le_full = ValD (ConP name_f (map (VarP . mkName . ("f_" ++)) fnames)) |
785 |
(NormalB . VarE . mkName $ oname_f) [] |
786 |
le_part = ValD (ConP name_p (map (VarP . mkName . ("p_" ++)) fnames)) |
787 |
(NormalB . VarE . mkName $ oname_p) [] |
788 |
obj_new = foldl (\accu vname -> AppE accu (VarE vname)) (ConE name_f) |
789 |
$ map (mkName . ("n_" ++)) fnames |
790 |
le_new <- mapM buildFromMaybe fnames |
791 |
funt <- [t| $(conT name_f) -> $(conT name_p) -> $(conT name_f) |] |
792 |
let sig = SigD fun_name funt |
793 |
fclause = Clause [VarP (mkName oname_f), VarP (mkName oname_p)] |
794 |
(NormalB $ LetE (le_full:le_part:le_new) obj_new) [] |
795 |
fun = FunD fun_name [fclause] |
796 |
return [sig, fun] |