root / htools / Ganeti / THH.hs @ d8cb8e13
History | View | Annotate | Download (29.6 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 |
, tagsFields |
51 |
, buildObject |
52 |
, buildObjectSerialisation |
53 |
, buildParam |
54 |
, Container |
55 |
) where |
56 |
|
57 |
import Control.Arrow |
58 |
import Control.Monad (liftM, liftM2) |
59 |
import Data.Char |
60 |
import Data.List |
61 |
import qualified Data.Map as M |
62 |
import qualified Data.Set as Set |
63 |
import Language.Haskell.TH |
64 |
|
65 |
import qualified Text.JSON as JSON |
66 |
|
67 |
import Ganeti.HTools.JSON |
68 |
|
69 |
-- * Exported types |
70 |
|
71 |
type Container = M.Map String |
72 |
|
73 |
-- | Serialised field data type. |
74 |
data Field = Field { fieldName :: String |
75 |
, fieldType :: Q Type |
76 |
, fieldRead :: Maybe (Q Exp) |
77 |
, fieldShow :: Maybe (Q Exp) |
78 |
, fieldDefault :: Maybe (Q Exp) |
79 |
, fieldConstr :: Maybe String |
80 |
, fieldIsContainer :: Bool |
81 |
, fieldIsOptional :: Bool |
82 |
} |
83 |
|
84 |
-- | Generates a simple field. |
85 |
simpleField :: String -> Q Type -> Field |
86 |
simpleField fname ftype = |
87 |
Field { fieldName = fname |
88 |
, fieldType = ftype |
89 |
, fieldRead = Nothing |
90 |
, fieldShow = Nothing |
91 |
, fieldDefault = Nothing |
92 |
, fieldConstr = Nothing |
93 |
, fieldIsContainer = False |
94 |
, fieldIsOptional = False |
95 |
} |
96 |
|
97 |
-- | Sets the renamed constructor field. |
98 |
renameField :: String -> Field -> Field |
99 |
renameField constrName field = field { fieldConstr = Just constrName } |
100 |
|
101 |
-- | Sets the default value on a field (makes it optional with a |
102 |
-- default value). |
103 |
defaultField :: Q Exp -> Field -> Field |
104 |
defaultField defval field = field { fieldDefault = Just defval } |
105 |
|
106 |
-- | Marks a field optional (turning its base type into a Maybe). |
107 |
optionalField :: Field -> Field |
108 |
optionalField field = field { fieldIsOptional = True } |
109 |
|
110 |
-- | Marks a field as a container. |
111 |
containerField :: Field -> Field |
112 |
containerField field = field { fieldIsContainer = True } |
113 |
|
114 |
-- | Sets custom functions on a field. |
115 |
customField :: Name -- ^ The name of the read function |
116 |
-> Name -- ^ The name of the show function |
117 |
-> Field -- ^ The original field |
118 |
-> Field -- ^ Updated field |
119 |
customField readfn showfn field = |
120 |
field { fieldRead = Just (varE readfn), fieldShow = Just (varE showfn) } |
121 |
|
122 |
fieldRecordName :: Field -> String |
123 |
fieldRecordName (Field { fieldName = name, fieldConstr = alias }) = |
124 |
maybe (camelCase name) id alias |
125 |
|
126 |
-- | Computes the preferred variable name to use for the value of this |
127 |
-- field. If the field has a specific constructor name, then we use a |
128 |
-- first-letter-lowercased version of that; otherwise, we simply use |
129 |
-- the field name. See also 'fieldRecordName'. |
130 |
fieldVariable :: Field -> String |
131 |
fieldVariable f = |
132 |
case (fieldConstr f) of |
133 |
Just name -> ensureLower name |
134 |
_ -> map (\c -> if c == '-' then '_' else c) $ fieldName f |
135 |
|
136 |
actualFieldType :: Field -> Q Type |
137 |
actualFieldType f | fieldIsContainer f = [t| Container $t |] |
138 |
| fieldIsOptional f = [t| Maybe $t |] |
139 |
| otherwise = t |
140 |
where t = fieldType f |
141 |
|
142 |
checkNonOptDef :: (Monad m) => Field -> m () |
143 |
checkNonOptDef (Field { fieldIsOptional = True, fieldName = name }) = |
144 |
fail $ "Optional field " ++ name ++ " used in parameter declaration" |
145 |
checkNonOptDef (Field { fieldDefault = (Just _), fieldName = name }) = |
146 |
fail $ "Default field " ++ name ++ " used in parameter declaration" |
147 |
checkNonOptDef _ = return () |
148 |
|
149 |
-- | Produces the expression that will de-serialise a given |
150 |
-- field. Since some custom parsing functions might need to use the |
151 |
-- entire object, we do take and pass the object to any custom read |
152 |
-- functions. |
153 |
loadFn :: Field -- ^ The field definition |
154 |
-> Q Exp -- ^ The value of the field as existing in the JSON message |
155 |
-> Q Exp -- ^ The entire object in JSON object format |
156 |
-> Q Exp -- ^ Resulting expression |
157 |
loadFn (Field { fieldIsContainer = True }) expr _ = |
158 |
[| $expr >>= readContainer |] |
159 |
loadFn (Field { fieldRead = Just readfn }) expr o = [| $expr >>= $readfn $o |] |
160 |
loadFn _ expr _ = expr |
161 |
|
162 |
-- * Common field declarations |
163 |
|
164 |
timeStampFields :: [Field] |
165 |
timeStampFields = |
166 |
[ defaultField [| 0::Double |] $ simpleField "ctime" [t| Double |] |
167 |
, defaultField [| 0::Double |] $ simpleField "mtime" [t| Double |] |
168 |
] |
169 |
|
170 |
serialFields :: [Field] |
171 |
serialFields = |
172 |
[ renameField "Serial" $ simpleField "serial_no" [t| Int |] ] |
173 |
|
174 |
uuidFields :: [Field] |
175 |
uuidFields = [ simpleField "uuid" [t| String |] ] |
176 |
|
177 |
-- | Tag field description. |
178 |
tagsFields :: [Field] |
179 |
tagsFields = [ defaultField [| Set.empty |] $ |
180 |
simpleField "tags" [t| Set.Set String |] ] |
181 |
|
182 |
-- * Helper functions |
183 |
|
184 |
-- | Ensure first letter is lowercase. |
185 |
-- |
186 |
-- Used to convert type name to function prefix, e.g. in @data Aa -> |
187 |
-- aaToRaw@. |
188 |
ensureLower :: String -> String |
189 |
ensureLower [] = [] |
190 |
ensureLower (x:xs) = toLower x:xs |
191 |
|
192 |
-- | Ensure first letter is uppercase. |
193 |
-- |
194 |
-- Used to convert constructor name to component |
195 |
ensureUpper :: String -> String |
196 |
ensureUpper [] = [] |
197 |
ensureUpper (x:xs) = toUpper x:xs |
198 |
|
199 |
-- | Helper for quoted expressions. |
200 |
varNameE :: String -> Q Exp |
201 |
varNameE = varE . mkName |
202 |
|
203 |
-- | showJSON as an expression, for reuse. |
204 |
showJSONE :: Q Exp |
205 |
showJSONE = varNameE "showJSON" |
206 |
|
207 |
-- | ToRaw function name. |
208 |
toRawName :: String -> Name |
209 |
toRawName = mkName . (++ "ToRaw") . ensureLower |
210 |
|
211 |
-- | FromRaw function name. |
212 |
fromRawName :: String -> Name |
213 |
fromRawName = mkName . (++ "FromRaw") . ensureLower |
214 |
|
215 |
-- | Converts a name to it's varE/litE representations. |
216 |
-- |
217 |
reprE :: Either String Name -> Q Exp |
218 |
reprE = either stringE varE |
219 |
|
220 |
-- | Smarter function application. |
221 |
-- |
222 |
-- This does simply f x, except that if is 'id', it will skip it, in |
223 |
-- order to generate more readable code when using -ddump-splices. |
224 |
appFn :: Exp -> Exp -> Exp |
225 |
appFn f x | f == VarE 'id = x |
226 |
| otherwise = AppE f x |
227 |
|
228 |
-- | Container loader |
229 |
readContainer :: (Monad m, JSON.JSON a) => |
230 |
JSON.JSObject JSON.JSValue -> m (Container a) |
231 |
readContainer obj = do |
232 |
let kjvlist = JSON.fromJSObject obj |
233 |
kalist <- mapM (\(k, v) -> fromKeyValue k v >>= \a -> return (k, a)) kjvlist |
234 |
return $ M.fromList kalist |
235 |
|
236 |
-- | Container dumper |
237 |
showContainer :: (JSON.JSON a) => Container a -> JSON.JSValue |
238 |
showContainer = JSON.makeObj . map (second JSON.showJSON) . M.toList |
239 |
|
240 |
-- * Template code for simple raw type-equivalent ADTs |
241 |
|
242 |
-- | Generates a data type declaration. |
243 |
-- |
244 |
-- The type will have a fixed list of instances. |
245 |
strADTDecl :: Name -> [String] -> Dec |
246 |
strADTDecl name constructors = |
247 |
DataD [] name [] |
248 |
(map (flip NormalC [] . mkName) constructors) |
249 |
[''Show, ''Read, ''Eq, ''Enum, ''Bounded, ''Ord] |
250 |
|
251 |
-- | Generates a toRaw function. |
252 |
-- |
253 |
-- This generates a simple function of the form: |
254 |
-- |
255 |
-- @ |
256 |
-- nameToRaw :: Name -> /traw/ |
257 |
-- nameToRaw Cons1 = var1 |
258 |
-- nameToRaw Cons2 = \"value2\" |
259 |
-- @ |
260 |
genToRaw :: Name -> Name -> Name -> [(String, Either String Name)] -> Q [Dec] |
261 |
genToRaw traw fname tname constructors = do |
262 |
let sigt = AppT (AppT ArrowT (ConT tname)) (ConT traw) |
263 |
-- the body clauses, matching on the constructor and returning the |
264 |
-- raw value |
265 |
clauses <- mapM (\(c, v) -> clause [recP (mkName c) []] |
266 |
(normalB (reprE v)) []) constructors |
267 |
return [SigD fname sigt, FunD fname clauses] |
268 |
|
269 |
-- | Generates a fromRaw function. |
270 |
-- |
271 |
-- The function generated is monadic and can fail parsing the |
272 |
-- raw value. It is of the form: |
273 |
-- |
274 |
-- @ |
275 |
-- nameFromRaw :: (Monad m) => /traw/ -> m Name |
276 |
-- nameFromRaw s | s == var1 = Cons1 |
277 |
-- | s == \"value2\" = Cons2 |
278 |
-- | otherwise = fail /.../ |
279 |
-- @ |
280 |
genFromRaw :: Name -> Name -> Name -> [(String, Name)] -> Q [Dec] |
281 |
genFromRaw traw fname tname constructors = do |
282 |
-- signature of form (Monad m) => String -> m $name |
283 |
sigt <- [t| (Monad m) => $(conT traw) -> m $(conT tname) |] |
284 |
-- clauses for a guarded pattern |
285 |
let varp = mkName "s" |
286 |
varpe = varE varp |
287 |
clauses <- mapM (\(c, v) -> do |
288 |
-- the clause match condition |
289 |
g <- normalG [| $varpe == $(varE v) |] |
290 |
-- the clause result |
291 |
r <- [| return $(conE (mkName c)) |] |
292 |
return (g, r)) constructors |
293 |
-- the otherwise clause (fallback) |
294 |
oth_clause <- do |
295 |
g <- normalG [| otherwise |] |
296 |
r <- [|fail ("Invalid string value for type " ++ |
297 |
$(litE (stringL (nameBase tname))) ++ ": " ++ show $varpe) |] |
298 |
return (g, r) |
299 |
let fun = FunD fname [Clause [VarP varp] |
300 |
(GuardedB (clauses++[oth_clause])) []] |
301 |
return [SigD fname sigt, fun] |
302 |
|
303 |
-- | Generates a data type from a given raw format. |
304 |
-- |
305 |
-- The format is expected to multiline. The first line contains the |
306 |
-- type name, and the rest of the lines must contain two words: the |
307 |
-- constructor name and then the string representation of the |
308 |
-- respective constructor. |
309 |
-- |
310 |
-- The function will generate the data type declaration, and then two |
311 |
-- functions: |
312 |
-- |
313 |
-- * /name/ToRaw, which converts the type to a raw type |
314 |
-- |
315 |
-- * /name/FromRaw, which (monadically) converts from a raw type to the type |
316 |
-- |
317 |
-- Note that this is basically just a custom show/read instance, |
318 |
-- nothing else. |
319 |
declareADT :: Name -> String -> [(String, Name)] -> Q [Dec] |
320 |
declareADT traw sname cons = do |
321 |
let name = mkName sname |
322 |
ddecl = strADTDecl name (map fst cons) |
323 |
-- process cons in the format expected by genToRaw |
324 |
cons' = map (\(a, b) -> (a, Right b)) cons |
325 |
toraw <- genToRaw traw (toRawName sname) name cons' |
326 |
fromraw <- genFromRaw traw (fromRawName sname) name cons |
327 |
return $ ddecl:toraw ++ fromraw |
328 |
|
329 |
declareIADT :: String -> [(String, Name)] -> Q [Dec] |
330 |
declareIADT = declareADT ''Int |
331 |
|
332 |
declareSADT :: String -> [(String, Name)] -> Q [Dec] |
333 |
declareSADT = declareADT ''String |
334 |
|
335 |
-- | Creates the showJSON member of a JSON instance declaration. |
336 |
-- |
337 |
-- This will create what is the equivalent of: |
338 |
-- |
339 |
-- @ |
340 |
-- showJSON = showJSON . /name/ToRaw |
341 |
-- @ |
342 |
-- |
343 |
-- in an instance JSON /name/ declaration |
344 |
genShowJSON :: String -> Q Dec |
345 |
genShowJSON name = do |
346 |
body <- [| JSON.showJSON . $(varE (toRawName name)) |] |
347 |
return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []] |
348 |
|
349 |
-- | Creates the readJSON member of a JSON instance declaration. |
350 |
-- |
351 |
-- This will create what is the equivalent of: |
352 |
-- |
353 |
-- @ |
354 |
-- readJSON s = case readJSON s of |
355 |
-- Ok s' -> /name/FromRaw s' |
356 |
-- Error e -> Error /description/ |
357 |
-- @ |
358 |
-- |
359 |
-- in an instance JSON /name/ declaration |
360 |
genReadJSON :: String -> Q Dec |
361 |
genReadJSON name = do |
362 |
let s = mkName "s" |
363 |
body <- [| case JSON.readJSON $(varE s) of |
364 |
JSON.Ok s' -> $(varE (fromRawName name)) s' |
365 |
JSON.Error e -> |
366 |
JSON.Error $ "Can't parse raw value for type " ++ |
367 |
$(stringE name) ++ ": " ++ e ++ " from " ++ |
368 |
show $(varE s) |
369 |
|] |
370 |
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []] |
371 |
|
372 |
-- | Generates a JSON instance for a given type. |
373 |
-- |
374 |
-- This assumes that the /name/ToRaw and /name/FromRaw functions |
375 |
-- have been defined as by the 'declareSADT' function. |
376 |
makeJSONInstance :: Name -> Q [Dec] |
377 |
makeJSONInstance name = do |
378 |
let base = nameBase name |
379 |
showJ <- genShowJSON base |
380 |
readJ <- genReadJSON base |
381 |
return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) [readJ,showJ]] |
382 |
|
383 |
-- * Template code for opcodes |
384 |
|
385 |
-- | Transforms a CamelCase string into an_underscore_based_one. |
386 |
deCamelCase :: String -> String |
387 |
deCamelCase = |
388 |
intercalate "_" . map (map toUpper) . groupBy (\_ b -> not $ isUpper b) |
389 |
|
390 |
-- | Transform an underscore_name into a CamelCase one. |
391 |
camelCase :: String -> String |
392 |
camelCase = concatMap (ensureUpper . drop 1) . |
393 |
groupBy (\_ b -> b /= '_' && b /= '-') . ('_':) |
394 |
|
395 |
-- | Computes the name of a given constructor. |
396 |
constructorName :: Con -> Q Name |
397 |
constructorName (NormalC name _) = return name |
398 |
constructorName (RecC name _) = return name |
399 |
constructorName x = fail $ "Unhandled constructor " ++ show x |
400 |
|
401 |
-- | Builds the generic constructor-to-string function. |
402 |
-- |
403 |
-- This generates a simple function of the following form: |
404 |
-- |
405 |
-- @ |
406 |
-- fname (ConStructorOne {}) = trans_fun("ConStructorOne") |
407 |
-- fname (ConStructorTwo {}) = trans_fun("ConStructorTwo") |
408 |
-- @ |
409 |
-- |
410 |
-- This builds a custom list of name/string pairs and then uses |
411 |
-- 'genToRaw' to actually generate the function |
412 |
genConstrToStr :: (String -> String) -> Name -> String -> Q [Dec] |
413 |
genConstrToStr trans_fun name fname = do |
414 |
TyConI (DataD _ _ _ cons _) <- reify name |
415 |
cnames <- mapM (liftM nameBase . constructorName) cons |
416 |
let svalues = map (Left . trans_fun) cnames |
417 |
genToRaw ''String (mkName fname) name $ zip cnames svalues |
418 |
|
419 |
-- | Constructor-to-string for OpCode. |
420 |
genOpID :: Name -> String -> Q [Dec] |
421 |
genOpID = genConstrToStr deCamelCase |
422 |
|
423 |
-- | OpCode parameter (field) type. |
424 |
type OpParam = (String, Q Type, Q Exp) |
425 |
|
426 |
-- | Generates the OpCode data type. |
427 |
-- |
428 |
-- This takes an opcode logical definition, and builds both the |
429 |
-- datatype and the JSON serialisation out of it. We can't use a |
430 |
-- generic serialisation since we need to be compatible with Ganeti's |
431 |
-- own, so we have a few quirks to work around. |
432 |
genOpCode :: String -- ^ Type name to use |
433 |
-> [(String, [Field])] -- ^ Constructor name and parameters |
434 |
-> Q [Dec] |
435 |
genOpCode name cons = do |
436 |
decl_d <- mapM (\(cname, fields) -> do |
437 |
-- we only need the type of the field, without Q |
438 |
fields' <- mapM actualFieldType fields |
439 |
let fields'' = zip (repeat NotStrict) fields' |
440 |
return $ NormalC (mkName cname) fields'') |
441 |
cons |
442 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq] |
443 |
|
444 |
(savesig, savefn) <- genSaveOpCode cons |
445 |
(loadsig, loadfn) <- genLoadOpCode cons |
446 |
return [declD, loadsig, loadfn, savesig, savefn] |
447 |
|
448 |
-- | Checks whether a given parameter is options. |
449 |
-- |
450 |
-- This requires that it's a 'Maybe'. |
451 |
isOptional :: Type -> Bool |
452 |
isOptional (AppT (ConT dt) _) | dt == ''Maybe = True |
453 |
isOptional _ = False |
454 |
|
455 |
-- | Generates the \"save\" clause for an entire opcode constructor. |
456 |
-- |
457 |
-- This matches the opcode with variables named the same as the |
458 |
-- constructor fields (just so that the spliced in code looks nicer), |
459 |
-- and passes those name plus the parameter definition to 'saveObjectField'. |
460 |
saveConstructor :: String -- ^ The constructor name |
461 |
-> [Field] -- ^ The parameter definitions for this |
462 |
-- constructor |
463 |
-> Q Clause -- ^ Resulting clause |
464 |
saveConstructor sname fields = do |
465 |
let cname = mkName sname |
466 |
fnames <- mapM (newName . fieldVariable) fields |
467 |
let pat = conP cname (map varP fnames) |
468 |
let felems = map (uncurry saveObjectField) (zip fnames fields) |
469 |
-- now build the OP_ID serialisation |
470 |
opid = [| [( $(stringE "OP_ID"), |
471 |
JSON.showJSON $(stringE . deCamelCase $ sname) )] |] |
472 |
flist = listE (opid:felems) |
473 |
-- and finally convert all this to a json object |
474 |
flist' = [| $(varNameE "makeObj") (concat $flist) |] |
475 |
clause [pat] (normalB flist') [] |
476 |
|
477 |
-- | Generates the main save opcode function. |
478 |
-- |
479 |
-- This builds a per-constructor match clause that contains the |
480 |
-- respective constructor-serialisation code. |
481 |
genSaveOpCode :: [(String, [Field])] -> Q (Dec, Dec) |
482 |
genSaveOpCode opdefs = do |
483 |
cclauses <- mapM (uncurry saveConstructor) opdefs |
484 |
let fname = mkName "saveOpCode" |
485 |
sigt <- [t| $(conT (mkName "OpCode")) -> JSON.JSValue |] |
486 |
return $ (SigD fname sigt, FunD fname cclauses) |
487 |
|
488 |
loadConstructor :: String -> [Field] -> Q Exp |
489 |
loadConstructor sname fields = do |
490 |
let name = mkName sname |
491 |
fbinds <- mapM loadObjectField fields |
492 |
let (fnames, fstmts) = unzip fbinds |
493 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
494 |
fstmts' = fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
495 |
return $ DoE fstmts' |
496 |
|
497 |
genLoadOpCode :: [(String, [Field])] -> Q (Dec, Dec) |
498 |
genLoadOpCode opdefs = do |
499 |
let fname = mkName "loadOpCode" |
500 |
arg1 = mkName "v" |
501 |
objname = mkName "o" |
502 |
opid = mkName "op_id" |
503 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
504 |
(JSON.readJSON $(varE arg1)) |] |
505 |
st2 <- bindS (varP opid) [| $(varNameE "fromObj") |
506 |
$(varE objname) $(stringE "OP_ID") |] |
507 |
-- the match results (per-constructor blocks) |
508 |
mexps <- mapM (uncurry loadConstructor) opdefs |
509 |
fails <- [| fail $ "Unknown opcode " ++ $(varE opid) |] |
510 |
let mpats = map (\(me, c) -> |
511 |
let mp = LitP . StringL . deCamelCase . fst $ c |
512 |
in Match mp (NormalB me) [] |
513 |
) $ zip mexps opdefs |
514 |
defmatch = Match WildP (NormalB fails) [] |
515 |
cst = NoBindS $ CaseE (VarE opid) $ mpats++[defmatch] |
516 |
body = DoE [st1, st2, cst] |
517 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT (mkName "OpCode")) |] |
518 |
return $ (SigD fname sigt, FunD fname [Clause [VarP arg1] (NormalB body) []]) |
519 |
|
520 |
-- * Template code for luxi |
521 |
|
522 |
-- | Constructor-to-string for LuxiOp. |
523 |
genStrOfOp :: Name -> String -> Q [Dec] |
524 |
genStrOfOp = genConstrToStr id |
525 |
|
526 |
-- | Constructor-to-string for MsgKeys. |
527 |
genStrOfKey :: Name -> String -> Q [Dec] |
528 |
genStrOfKey = genConstrToStr ensureLower |
529 |
|
530 |
-- | LuxiOp parameter type. |
531 |
type LuxiParam = (String, Q Type, Q Exp) |
532 |
|
533 |
-- | Generates the LuxiOp data type. |
534 |
-- |
535 |
-- This takes a Luxi operation definition and builds both the |
536 |
-- datatype and the function trnasforming the arguments to JSON. |
537 |
-- We can't use anything less generic, because the way different |
538 |
-- operations are serialized differs on both parameter- and top-level. |
539 |
-- |
540 |
-- There are three things to be defined for each parameter: |
541 |
-- |
542 |
-- * name |
543 |
-- |
544 |
-- * type |
545 |
-- |
546 |
-- * operation; this is the operation performed on the parameter before |
547 |
-- serialization |
548 |
-- |
549 |
genLuxiOp :: String -> [(String, [LuxiParam])] -> Q [Dec] |
550 |
genLuxiOp name cons = do |
551 |
decl_d <- mapM (\(cname, fields) -> do |
552 |
fields' <- mapM (\(_, qt, _) -> |
553 |
qt >>= \t -> return (NotStrict, t)) |
554 |
fields |
555 |
return $ NormalC (mkName cname) fields') |
556 |
cons |
557 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq] |
558 |
(savesig, savefn) <- genSaveLuxiOp cons |
559 |
req_defs <- declareSADT "LuxiReq" . |
560 |
map (\(str, _) -> ("Req" ++ str, mkName ("luxiReq" ++ str))) $ |
561 |
cons |
562 |
return $ [declD, savesig, savefn] ++ req_defs |
563 |
|
564 |
-- | Generates the \"save\" expression for a single luxi parameter. |
565 |
saveLuxiField :: Name -> LuxiParam -> Q Exp |
566 |
saveLuxiField fvar (_, qt, fn) = |
567 |
[| JSON.showJSON ( $(liftM2 appFn fn $ varE fvar) ) |] |
568 |
|
569 |
-- | Generates the \"save\" clause for entire LuxiOp constructor. |
570 |
saveLuxiConstructor :: (String, [LuxiParam]) -> Q Clause |
571 |
saveLuxiConstructor (sname, fields) = do |
572 |
let cname = mkName sname |
573 |
fnames = map (\(nm, _, _) -> mkName nm) fields |
574 |
pat = conP cname (map varP fnames) |
575 |
flist = map (uncurry saveLuxiField) (zip fnames fields) |
576 |
finval = if null flist |
577 |
then [| JSON.showJSON () |] |
578 |
else [| JSON.showJSON $(listE flist) |] |
579 |
clause [pat] (normalB finval) [] |
580 |
|
581 |
-- | Generates the main save LuxiOp function. |
582 |
genSaveLuxiOp :: [(String, [LuxiParam])]-> Q (Dec, Dec) |
583 |
genSaveLuxiOp opdefs = do |
584 |
sigt <- [t| $(conT (mkName "LuxiOp")) -> JSON.JSValue |] |
585 |
let fname = mkName "opToArgs" |
586 |
cclauses <- mapM saveLuxiConstructor opdefs |
587 |
return $ (SigD fname sigt, FunD fname cclauses) |
588 |
|
589 |
-- * "Objects" functionality |
590 |
|
591 |
-- | Extract the field's declaration from a Field structure. |
592 |
fieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
593 |
fieldTypeInfo field_pfx fd = do |
594 |
t <- actualFieldType fd |
595 |
let n = mkName . (field_pfx ++) . fieldRecordName $ fd |
596 |
return (n, NotStrict, t) |
597 |
|
598 |
-- | Build an object declaration. |
599 |
buildObject :: String -> String -> [Field] -> Q [Dec] |
600 |
buildObject sname field_pfx fields = do |
601 |
let name = mkName sname |
602 |
fields_d <- mapM (fieldTypeInfo field_pfx) fields |
603 |
let decl_d = RecC name fields_d |
604 |
let declD = DataD [] name [] [decl_d] [''Show, ''Read, ''Eq] |
605 |
ser_decls <- buildObjectSerialisation sname fields |
606 |
return $ declD:ser_decls |
607 |
|
608 |
buildObjectSerialisation :: String -> [Field] -> Q [Dec] |
609 |
buildObjectSerialisation sname fields = do |
610 |
let name = mkName sname |
611 |
savedecls <- genSaveObject saveObjectField sname fields |
612 |
(loadsig, loadfn) <- genLoadObject loadObjectField sname fields |
613 |
shjson <- objectShowJSON sname |
614 |
rdjson <- objectReadJSON sname |
615 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
616 |
[rdjson, shjson] |
617 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
618 |
|
619 |
genSaveObject :: (Name -> Field -> Q Exp) |
620 |
-> String -> [Field] -> Q [Dec] |
621 |
genSaveObject save_fn sname fields = do |
622 |
let name = mkName sname |
623 |
fnames <- mapM (newName . fieldVariable) fields |
624 |
let pat = conP name (map varP fnames) |
625 |
let tdname = mkName ("toDict" ++ sname) |
626 |
tdsigt <- [t| $(conT name) -> [(String, JSON.JSValue)] |] |
627 |
|
628 |
let felems = map (uncurry save_fn) (zip fnames fields) |
629 |
flist = listE felems |
630 |
-- and finally convert all this to a json object |
631 |
tdlist = [| concat $flist |] |
632 |
iname = mkName "i" |
633 |
tclause <- clause [pat] (normalB tdlist) [] |
634 |
cclause <- [| $(varNameE "makeObj") . $(varE tdname) |] |
635 |
let fname = mkName ("save" ++ sname) |
636 |
sigt <- [t| $(conT name) -> JSON.JSValue |] |
637 |
return [SigD tdname tdsigt, FunD tdname [tclause], |
638 |
SigD fname sigt, ValD (VarP fname) (NormalB cclause) []] |
639 |
|
640 |
saveObjectField :: Name -> Field -> Q Exp |
641 |
saveObjectField fvar field |
642 |
| isContainer = [| [( $nameE , JSON.showJSON . showContainer $ $fvarE)] |] |
643 |
| fisOptional = [| case $(varE fvar) of |
644 |
Nothing -> [] |
645 |
Just v -> [( $nameE, JSON.showJSON v)] |
646 |
|] |
647 |
| otherwise = case fieldShow field of |
648 |
Nothing -> [| [( $nameE, JSON.showJSON $fvarE)] |] |
649 |
Just fn -> [| let (actual, extra) = $fn $fvarE |
650 |
in extra ++ [( $nameE, JSON.showJSON actual)] |
651 |
|] |
652 |
where isContainer = fieldIsContainer field |
653 |
fisOptional = fieldIsOptional field |
654 |
nameE = stringE (fieldName field) |
655 |
fvarE = varE fvar |
656 |
|
657 |
objectShowJSON :: String -> Q Dec |
658 |
objectShowJSON name = do |
659 |
body <- [| JSON.showJSON . $(varE . mkName $ "save" ++ name) |] |
660 |
return $ FunD (mkName "showJSON") [Clause [] (NormalB body) []] |
661 |
|
662 |
genLoadObject :: (Field -> Q (Name, Stmt)) |
663 |
-> String -> [Field] -> Q (Dec, Dec) |
664 |
genLoadObject load_fn sname fields = do |
665 |
let name = mkName sname |
666 |
funname = mkName $ "load" ++ sname |
667 |
arg1 = mkName "v" |
668 |
objname = mkName "o" |
669 |
opid = mkName "op_id" |
670 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
671 |
(JSON.readJSON $(varE arg1)) |] |
672 |
fbinds <- mapM load_fn fields |
673 |
let (fnames, fstmts) = unzip fbinds |
674 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
675 |
fstmts' = st1:fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
676 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT name) |] |
677 |
return $ (SigD funname sigt, |
678 |
FunD funname [Clause [VarP arg1] (NormalB (DoE fstmts')) []]) |
679 |
|
680 |
loadObjectField :: Field -> Q (Name, Stmt) |
681 |
loadObjectField field = do |
682 |
let name = fieldVariable field |
683 |
fvar <- newName name |
684 |
-- these are used in all patterns below |
685 |
let objvar = varNameE "o" |
686 |
objfield = stringE (fieldName field) |
687 |
loadexp = |
688 |
if fieldIsOptional field |
689 |
then [| $(varNameE "maybeFromObj") $objvar $objfield |] |
690 |
else case fieldDefault field of |
691 |
Just defv -> |
692 |
[| $(varNameE "fromObjWithDefault") $objvar |
693 |
$objfield $defv |] |
694 |
Nothing -> [| $(varNameE "fromObj") $objvar $objfield |] |
695 |
bexp <- loadFn field loadexp objvar |
696 |
|
697 |
return (fvar, BindS (VarP fvar) bexp) |
698 |
|
699 |
objectReadJSON :: String -> Q Dec |
700 |
objectReadJSON name = do |
701 |
let s = mkName "s" |
702 |
body <- [| case JSON.readJSON $(varE s) of |
703 |
JSON.Ok s' -> $(varE .mkName $ "load" ++ name) s' |
704 |
JSON.Error e -> |
705 |
JSON.Error $ "Can't parse value for type " ++ |
706 |
$(stringE name) ++ ": " ++ e |
707 |
|] |
708 |
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []] |
709 |
|
710 |
-- * Inheritable parameter tables implementation |
711 |
|
712 |
-- | Compute parameter type names. |
713 |
paramTypeNames :: String -> (String, String) |
714 |
paramTypeNames root = ("Filled" ++ root ++ "Params", |
715 |
"Partial" ++ root ++ "Params") |
716 |
|
717 |
-- | Compute information about the type of a parameter field. |
718 |
paramFieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
719 |
paramFieldTypeInfo field_pfx fd = do |
720 |
t <- actualFieldType fd |
721 |
let n = mkName . (++ "P") . (field_pfx ++) . |
722 |
fieldRecordName $ fd |
723 |
return (n, NotStrict, AppT (ConT ''Maybe) t) |
724 |
|
725 |
-- | Build a parameter declaration. |
726 |
-- |
727 |
-- This function builds two different data structures: a /filled/ one, |
728 |
-- in which all fields are required, and a /partial/ one, in which all |
729 |
-- fields are optional. Due to the current record syntax issues, the |
730 |
-- fields need to be named differrently for the two structures, so the |
731 |
-- partial ones get a /P/ suffix. |
732 |
buildParam :: String -> String -> [Field] -> Q [Dec] |
733 |
buildParam sname field_pfx fields = do |
734 |
let (sname_f, sname_p) = paramTypeNames sname |
735 |
name_f = mkName sname_f |
736 |
name_p = mkName sname_p |
737 |
fields_f <- mapM (fieldTypeInfo field_pfx) fields |
738 |
fields_p <- mapM (paramFieldTypeInfo field_pfx) fields |
739 |
let decl_f = RecC name_f fields_f |
740 |
decl_p = RecC name_p fields_p |
741 |
let declF = DataD [] name_f [] [decl_f] [''Show, ''Read, ''Eq] |
742 |
declP = DataD [] name_p [] [decl_p] [''Show, ''Read, ''Eq] |
743 |
ser_decls_f <- buildObjectSerialisation sname_f fields |
744 |
ser_decls_p <- buildPParamSerialisation sname_p fields |
745 |
fill_decls <- fillParam sname field_pfx fields |
746 |
return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls |
747 |
|
748 |
buildPParamSerialisation :: String -> [Field] -> Q [Dec] |
749 |
buildPParamSerialisation sname fields = do |
750 |
let name = mkName sname |
751 |
savedecls <- genSaveObject savePParamField sname fields |
752 |
(loadsig, loadfn) <- genLoadObject loadPParamField sname fields |
753 |
shjson <- objectShowJSON sname |
754 |
rdjson <- objectReadJSON sname |
755 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
756 |
[rdjson, shjson] |
757 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
758 |
|
759 |
savePParamField :: Name -> Field -> Q Exp |
760 |
savePParamField fvar field = do |
761 |
checkNonOptDef field |
762 |
let actualVal = mkName "v" |
763 |
normalexpr <- saveObjectField actualVal field |
764 |
-- we have to construct the block here manually, because we can't |
765 |
-- splice-in-splice |
766 |
return $ CaseE (VarE fvar) [ Match (ConP 'Nothing []) |
767 |
(NormalB (ConE '[])) [] |
768 |
, Match (ConP 'Just [VarP actualVal]) |
769 |
(NormalB normalexpr) [] |
770 |
] |
771 |
loadPParamField :: Field -> Q (Name, Stmt) |
772 |
loadPParamField field = do |
773 |
checkNonOptDef field |
774 |
let name = fieldName field |
775 |
fvar <- newName name |
776 |
-- these are used in all patterns below |
777 |
let objvar = varNameE "o" |
778 |
objfield = stringE name |
779 |
loadexp = [| $(varNameE "maybeFromObj") $objvar $objfield |] |
780 |
bexp <- loadFn field loadexp objvar |
781 |
return (fvar, BindS (VarP fvar) bexp) |
782 |
|
783 |
-- | Builds a simple declaration of type @n_x = fromMaybe f_x p_x@. |
784 |
buildFromMaybe :: String -> Q Dec |
785 |
buildFromMaybe fname = |
786 |
valD (varP (mkName $ "n_" ++ fname)) |
787 |
(normalB [| $(varNameE "fromMaybe") |
788 |
$(varNameE $ "f_" ++ fname) |
789 |
$(varNameE $ "p_" ++ fname) |]) [] |
790 |
|
791 |
fillParam :: String -> String -> [Field] -> Q [Dec] |
792 |
fillParam sname field_pfx fields = do |
793 |
let fnames = map (\fd -> field_pfx ++ fieldRecordName fd) fields |
794 |
(sname_f, sname_p) = paramTypeNames sname |
795 |
oname_f = "fobj" |
796 |
oname_p = "pobj" |
797 |
name_f = mkName sname_f |
798 |
name_p = mkName sname_p |
799 |
fun_name = mkName $ "fill" ++ sname ++ "Params" |
800 |
le_full = ValD (ConP name_f (map (VarP . mkName . ("f_" ++)) fnames)) |
801 |
(NormalB . VarE . mkName $ oname_f) [] |
802 |
le_part = ValD (ConP name_p (map (VarP . mkName . ("p_" ++)) fnames)) |
803 |
(NormalB . VarE . mkName $ oname_p) [] |
804 |
obj_new = foldl (\accu vname -> AppE accu (VarE vname)) (ConE name_f) |
805 |
$ map (mkName . ("n_" ++)) fnames |
806 |
le_new <- mapM buildFromMaybe fnames |
807 |
funt <- [t| $(conT name_f) -> $(conT name_p) -> $(conT name_f) |] |
808 |
let sig = SigD fun_name funt |
809 |
fclause = Clause [VarP (mkName oname_f), VarP (mkName oname_p)] |
810 |
(NormalB $ LetE (le_full:le_part:le_new) obj_new) [] |
811 |
fun = FunD fun_name [fclause] |
812 |
return [sig, fun] |