root / htools / Ganeti / THH.hs @ 706f7f51
History | View | Annotate | Download (30.4 kB)
1 |
{-# LANGUAGE TemplateHaskell, QuasiQuotes #-} |
---|---|
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 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 |
, noDefault |
38 |
, genStrOfOp |
39 |
, genStrOfKey |
40 |
, genLuxiOp |
41 |
, Field |
42 |
, simpleField |
43 |
, defaultField |
44 |
, optionalField |
45 |
, renameField |
46 |
, containerField |
47 |
, customField |
48 |
, timeStampFields |
49 |
, uuidFields |
50 |
, serialFields |
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 Language.Haskell.TH |
63 |
|
64 |
import qualified Text.JSON as JSON |
65 |
|
66 |
import Ganeti.HTools.JSON |
67 |
|
68 |
-- * Exported types |
69 |
|
70 |
type Container = M.Map String |
71 |
|
72 |
-- | Serialised field data type. |
73 |
data Field = Field { fieldName :: String |
74 |
, fieldType :: Q Type |
75 |
, fieldRead :: Maybe (Q Exp) |
76 |
, fieldShow :: Maybe (Q Exp) |
77 |
, fieldDefault :: Maybe (Q Exp) |
78 |
, fieldConstr :: Maybe String |
79 |
, fieldIsContainer :: Bool |
80 |
, fieldIsOptional :: Bool |
81 |
} |
82 |
|
83 |
-- | Generates a simple field. |
84 |
simpleField :: String -> Q Type -> Field |
85 |
simpleField fname ftype = |
86 |
Field { fieldName = fname |
87 |
, fieldType = ftype |
88 |
, fieldRead = Nothing |
89 |
, fieldShow = Nothing |
90 |
, fieldDefault = Nothing |
91 |
, fieldConstr = Nothing |
92 |
, fieldIsContainer = False |
93 |
, fieldIsOptional = False |
94 |
} |
95 |
|
96 |
-- | Sets the renamed constructor field. |
97 |
renameField :: String -> Field -> Field |
98 |
renameField constrName field = field { fieldConstr = Just constrName } |
99 |
|
100 |
-- | Sets the default value on a field (makes it optional with a |
101 |
-- default value). |
102 |
defaultField :: Q Exp -> Field -> Field |
103 |
defaultField defval field = field { fieldDefault = Just defval } |
104 |
|
105 |
-- | Marks a field optional (turning its base type into a Maybe). |
106 |
optionalField :: Field -> Field |
107 |
optionalField field = field { fieldIsOptional = True } |
108 |
|
109 |
-- | Marks a field as a container. |
110 |
containerField :: Field -> Field |
111 |
containerField field = field { fieldIsContainer = True } |
112 |
|
113 |
-- | Sets custom functions on a field. |
114 |
customField :: Q Exp -> Q Exp -> Field -> Field |
115 |
customField readfn showfn field = |
116 |
field { fieldRead = Just readfn, fieldShow = Just showfn } |
117 |
|
118 |
fieldRecordName :: Field -> String |
119 |
fieldRecordName (Field { fieldName = name, fieldConstr = alias }) = |
120 |
maybe (camelCase name) id alias |
121 |
|
122 |
fieldVariable :: Field -> String |
123 |
fieldVariable = map toLower . fieldRecordName |
124 |
|
125 |
actualFieldType :: Field -> Q Type |
126 |
actualFieldType f | fieldIsContainer f = [t| Container $t |] |
127 |
| fieldIsOptional f = [t| Maybe $t |] |
128 |
| otherwise = t |
129 |
where t = fieldType f |
130 |
|
131 |
checkNonOptDef :: (Monad m) => Field -> m () |
132 |
checkNonOptDef (Field { fieldIsOptional = True, fieldName = name }) = |
133 |
fail $ "Optional field " ++ name ++ " used in parameter declaration" |
134 |
checkNonOptDef (Field { fieldDefault = (Just _), fieldName = name }) = |
135 |
fail $ "Default field " ++ name ++ " used in parameter declaration" |
136 |
checkNonOptDef _ = return () |
137 |
|
138 |
loadFn :: Field -> Q Exp -> Q Exp |
139 |
loadFn (Field { fieldIsContainer = True }) expr = [| $expr >>= readContainer |] |
140 |
loadFn (Field { fieldRead = Just readfn }) expr = [| $expr >>= $readfn |] |
141 |
loadFn _ expr = expr |
142 |
|
143 |
saveFn :: Field -> Q Exp -> Q Exp |
144 |
saveFn (Field { fieldIsContainer = True }) expr = [| showContainer $expr |] |
145 |
saveFn (Field { fieldRead = Just readfn }) expr = [| $readfn $expr |] |
146 |
saveFn _ expr = expr |
147 |
|
148 |
-- * Common field declarations |
149 |
|
150 |
timeStampFields :: [Field] |
151 |
timeStampFields = |
152 |
[ defaultField [| 0::Double |] $ simpleField "ctime" [t| Double |] |
153 |
, defaultField [| 0::Double |] $ simpleField "mtime" [t| Double |] |
154 |
] |
155 |
|
156 |
serialFields :: [Field] |
157 |
serialFields = |
158 |
[ renameField "Serial" $ simpleField "serial_no" [t| Int |] ] |
159 |
|
160 |
uuidFields :: [Field] |
161 |
uuidFields = [ simpleField "uuid" [t| String |] ] |
162 |
|
163 |
-- * Helper functions |
164 |
|
165 |
-- | Ensure first letter is lowercase. |
166 |
-- |
167 |
-- Used to convert type name to function prefix, e.g. in @data Aa -> |
168 |
-- aaToRaw@. |
169 |
ensureLower :: String -> String |
170 |
ensureLower [] = [] |
171 |
ensureLower (x:xs) = toLower x:xs |
172 |
|
173 |
-- | Ensure first letter is uppercase. |
174 |
-- |
175 |
-- Used to convert constructor name to component |
176 |
ensureUpper :: String -> String |
177 |
ensureUpper [] = [] |
178 |
ensureUpper (x:xs) = toUpper x:xs |
179 |
|
180 |
-- | Helper for quoted expressions. |
181 |
varNameE :: String -> Q Exp |
182 |
varNameE = varE . mkName |
183 |
|
184 |
-- | showJSON as an expression, for reuse. |
185 |
showJSONE :: Q Exp |
186 |
showJSONE = varNameE "showJSON" |
187 |
|
188 |
-- | ToRaw function name. |
189 |
toRawName :: String -> Name |
190 |
toRawName = mkName . (++ "ToRaw") . ensureLower |
191 |
|
192 |
-- | FromRaw function name. |
193 |
fromRawName :: String -> Name |
194 |
fromRawName = mkName . (++ "FromRaw") . ensureLower |
195 |
|
196 |
-- | Converts a name to it's varE/litE representations. |
197 |
-- |
198 |
reprE :: Either String Name -> Q Exp |
199 |
reprE = either stringE varE |
200 |
|
201 |
-- | Smarter function application. |
202 |
-- |
203 |
-- This does simply f x, except that if is 'id', it will skip it, in |
204 |
-- order to generate more readable code when using -ddump-splices. |
205 |
appFn :: Exp -> Exp -> Exp |
206 |
appFn f x | f == VarE 'id = x |
207 |
| otherwise = AppE f x |
208 |
|
209 |
-- | Container loader |
210 |
readContainer :: (Monad m, JSON.JSON a) => |
211 |
JSON.JSObject JSON.JSValue -> m (Container a) |
212 |
readContainer obj = do |
213 |
let kjvlist = JSON.fromJSObject obj |
214 |
kalist <- mapM (\(k, v) -> fromKeyValue k v >>= \a -> return (k, a)) kjvlist |
215 |
return $ M.fromList kalist |
216 |
|
217 |
-- | Container dumper |
218 |
showContainer :: (JSON.JSON a) => Container a -> JSON.JSValue |
219 |
showContainer = JSON.makeObj . map (second JSON.showJSON) . M.toList |
220 |
|
221 |
-- * Template code for simple raw type-equivalent ADTs |
222 |
|
223 |
-- | Generates a data type declaration. |
224 |
-- |
225 |
-- The type will have a fixed list of instances. |
226 |
strADTDecl :: Name -> [String] -> Dec |
227 |
strADTDecl name constructors = |
228 |
DataD [] name [] |
229 |
(map (flip NormalC [] . mkName) constructors) |
230 |
[''Show, ''Read, ''Eq, ''Enum, ''Bounded, ''Ord] |
231 |
|
232 |
-- | Generates a toRaw function. |
233 |
-- |
234 |
-- This generates a simple function of the form: |
235 |
-- |
236 |
-- @ |
237 |
-- nameToRaw :: Name -> /traw/ |
238 |
-- nameToRaw Cons1 = var1 |
239 |
-- nameToRaw Cons2 = \"value2\" |
240 |
-- @ |
241 |
genToRaw :: Name -> Name -> Name -> [(String, Either String Name)] -> Q [Dec] |
242 |
genToRaw traw fname tname constructors = do |
243 |
sigt <- [t| $(conT tname) -> $(conT traw) |] |
244 |
-- the body clauses, matching on the constructor and returning the |
245 |
-- raw value |
246 |
clauses <- mapM (\(c, v) -> clause [recP (mkName c) []] |
247 |
(normalB (reprE v)) []) constructors |
248 |
return [SigD fname sigt, FunD fname clauses] |
249 |
|
250 |
-- | Generates a fromRaw function. |
251 |
-- |
252 |
-- The function generated is monadic and can fail parsing the |
253 |
-- raw value. It is of the form: |
254 |
-- |
255 |
-- @ |
256 |
-- nameFromRaw :: (Monad m) => /traw/ -> m Name |
257 |
-- nameFromRaw s | s == var1 = Cons1 |
258 |
-- | s == \"value2\" = Cons2 |
259 |
-- | otherwise = fail /.../ |
260 |
-- @ |
261 |
genFromRaw :: Name -> Name -> Name -> [(String, Name)] -> Q [Dec] |
262 |
genFromRaw traw fname tname constructors = do |
263 |
-- signature of form (Monad m) => String -> m $name |
264 |
sigt <- [t| (Monad m) => $(conT traw) -> m $(conT tname) |] |
265 |
-- clauses for a guarded pattern |
266 |
let varp = mkName "s" |
267 |
varpe = varE varp |
268 |
clauses <- mapM (\(c, v) -> do |
269 |
-- the clause match condition |
270 |
g <- normalG [| $varpe == $(varE v) |] |
271 |
-- the clause result |
272 |
r <- [| return $(conE (mkName c)) |] |
273 |
return (g, r)) constructors |
274 |
-- the otherwise clause (fallback) |
275 |
oth_clause <- do |
276 |
g <- normalG [| otherwise |] |
277 |
r <- [|fail ("Invalid string value for type " ++ |
278 |
$(litE (stringL (nameBase tname))) ++ ": " ++ show $varpe) |] |
279 |
return (g, r) |
280 |
let fun = FunD fname [Clause [VarP varp] |
281 |
(GuardedB (clauses++[oth_clause])) []] |
282 |
return [SigD fname sigt, fun] |
283 |
|
284 |
-- | Generates a data type from a given raw format. |
285 |
-- |
286 |
-- The format is expected to multiline. The first line contains the |
287 |
-- type name, and the rest of the lines must contain two words: the |
288 |
-- constructor name and then the string representation of the |
289 |
-- respective constructor. |
290 |
-- |
291 |
-- The function will generate the data type declaration, and then two |
292 |
-- functions: |
293 |
-- |
294 |
-- * /name/ToRaw, which converts the type to a raw type |
295 |
-- |
296 |
-- * /name/FromRaw, which (monadically) converts from a raw type to the type |
297 |
-- |
298 |
-- Note that this is basically just a custom show/read instance, |
299 |
-- nothing else. |
300 |
declareADT :: Name -> String -> [(String, Name)] -> Q [Dec] |
301 |
declareADT traw sname cons = do |
302 |
let name = mkName sname |
303 |
ddecl = strADTDecl name (map fst cons) |
304 |
-- process cons in the format expected by genToRaw |
305 |
cons' = map (\(a, b) -> (a, Right b)) cons |
306 |
toraw <- genToRaw traw (toRawName sname) name cons' |
307 |
fromraw <- genFromRaw traw (fromRawName sname) name cons |
308 |
return $ ddecl:toraw ++ fromraw |
309 |
|
310 |
declareIADT :: String -> [(String, Name)] -> Q [Dec] |
311 |
declareIADT = declareADT ''Int |
312 |
|
313 |
declareSADT :: String -> [(String, Name)] -> Q [Dec] |
314 |
declareSADT = declareADT ''String |
315 |
|
316 |
-- | Creates the showJSON member of a JSON instance declaration. |
317 |
-- |
318 |
-- This will create what is the equivalent of: |
319 |
-- |
320 |
-- @ |
321 |
-- showJSON = showJSON . /name/ToRaw |
322 |
-- @ |
323 |
-- |
324 |
-- in an instance JSON /name/ declaration |
325 |
genShowJSON :: String -> Q [Dec] |
326 |
genShowJSON name = [d| showJSON = JSON.showJSON . $(varE (toRawName name)) |] |
327 |
|
328 |
-- | Creates the readJSON member of a JSON instance declaration. |
329 |
-- |
330 |
-- This will create what is the equivalent of: |
331 |
-- |
332 |
-- @ |
333 |
-- readJSON s = case readJSON s of |
334 |
-- Ok s' -> /name/FromRaw s' |
335 |
-- Error e -> Error /description/ |
336 |
-- @ |
337 |
-- |
338 |
-- in an instance JSON /name/ declaration |
339 |
genReadJSON :: String -> Q Dec |
340 |
genReadJSON name = do |
341 |
let s = mkName "s" |
342 |
body <- [| case JSON.readJSON $(varE s) of |
343 |
JSON.Ok s' -> $(varE (fromRawName name)) s' |
344 |
JSON.Error e -> |
345 |
JSON.Error $ "Can't parse raw value for type " ++ |
346 |
$(stringE name) ++ ": " ++ e |
347 |
|] |
348 |
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []] |
349 |
|
350 |
-- | Generates a JSON instance for a given type. |
351 |
-- |
352 |
-- This assumes that the /name/ToRaw and /name/FromRaw functions |
353 |
-- have been defined as by the 'declareSADT' function. |
354 |
makeJSONInstance :: Name -> Q [Dec] |
355 |
makeJSONInstance name = do |
356 |
let base = nameBase name |
357 |
showJ <- genShowJSON base |
358 |
readJ <- genReadJSON base |
359 |
return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) (readJ:showJ)] |
360 |
|
361 |
-- * Template code for opcodes |
362 |
|
363 |
-- | Transforms a CamelCase string into an_underscore_based_one. |
364 |
deCamelCase :: String -> String |
365 |
deCamelCase = |
366 |
intercalate "_" . map (map toUpper) . groupBy (\_ b -> not $ isUpper b) |
367 |
|
368 |
-- | Transform an underscore_name into a CamelCase one. |
369 |
camelCase :: String -> String |
370 |
camelCase = concatMap (ensureUpper . drop 1) . |
371 |
groupBy (\_ b -> b /= '_') . ('_':) |
372 |
|
373 |
-- | Computes the name of a given constructor. |
374 |
constructorName :: Con -> Q Name |
375 |
constructorName (NormalC name _) = return name |
376 |
constructorName (RecC name _) = return name |
377 |
constructorName x = fail $ "Unhandled constructor " ++ show x |
378 |
|
379 |
-- | Builds the generic constructor-to-string function. |
380 |
-- |
381 |
-- This generates a simple function of the following form: |
382 |
-- |
383 |
-- @ |
384 |
-- fname (ConStructorOne {}) = trans_fun("ConStructorOne") |
385 |
-- fname (ConStructorTwo {}) = trans_fun("ConStructorTwo") |
386 |
-- @ |
387 |
-- |
388 |
-- This builds a custom list of name/string pairs and then uses |
389 |
-- 'genToRaw' to actually generate the function |
390 |
genConstrToStr :: (String -> String) -> Name -> String -> Q [Dec] |
391 |
genConstrToStr trans_fun name fname = do |
392 |
TyConI (DataD _ _ _ cons _) <- reify name |
393 |
cnames <- mapM (liftM nameBase . constructorName) cons |
394 |
let svalues = map (Left . trans_fun) cnames |
395 |
genToRaw ''String (mkName fname) name $ zip cnames svalues |
396 |
|
397 |
-- | Constructor-to-string for OpCode. |
398 |
genOpID :: Name -> String -> Q [Dec] |
399 |
genOpID = genConstrToStr deCamelCase |
400 |
|
401 |
-- | OpCode parameter (field) type. |
402 |
type OpParam = (String, Q Type, Q Exp) |
403 |
|
404 |
-- | Generates the OpCode data type. |
405 |
-- |
406 |
-- This takes an opcode logical definition, and builds both the |
407 |
-- datatype and the JSON serialisation out of it. We can't use a |
408 |
-- generic serialisation since we need to be compatible with Ganeti's |
409 |
-- own, so we have a few quirks to work around. |
410 |
-- |
411 |
-- There are three things to be defined for each parameter: |
412 |
-- |
413 |
-- * name |
414 |
-- |
415 |
-- * type; if this is 'Maybe', will only be serialised if it's a |
416 |
-- 'Just' value |
417 |
-- |
418 |
-- * default; if missing, won't raise an exception, but will instead |
419 |
-- use the default |
420 |
-- |
421 |
genOpCode :: String -- ^ Type name to use |
422 |
-> [(String, [OpParam])] -- ^ Constructor name and parameters |
423 |
-> Q [Dec] |
424 |
genOpCode name cons = do |
425 |
decl_d <- mapM (\(cname, fields) -> do |
426 |
-- we only need the type of the field, without Q |
427 |
fields' <- mapM (\(_, qt, _) -> |
428 |
qt >>= \t -> return (NotStrict, t)) |
429 |
fields |
430 |
return $ NormalC (mkName cname) fields') |
431 |
cons |
432 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read, ''Eq] |
433 |
|
434 |
(savesig, savefn) <- genSaveOpCode cons |
435 |
(loadsig, loadfn) <- genLoadOpCode cons |
436 |
return [declD, loadsig, loadfn, savesig, savefn] |
437 |
|
438 |
-- | Checks whether a given parameter is options. |
439 |
-- |
440 |
-- This requires that it's a 'Maybe'. |
441 |
isOptional :: Type -> Bool |
442 |
isOptional (AppT (ConT dt) _) | dt == ''Maybe = True |
443 |
isOptional _ = False |
444 |
|
445 |
-- | Generates the \"save\" expression for a single opcode parameter. |
446 |
-- |
447 |
-- There is only one special handling mode: if the parameter is of |
448 |
-- 'Maybe' type, then we only save it if it's a 'Just' value, |
449 |
-- otherwise we skip it. |
450 |
saveField :: Name -- ^ The name of variable that contains the value |
451 |
-> OpParam -- ^ Parameter definition |
452 |
-> Q Exp |
453 |
saveField fvar (fname, qt, _) = do |
454 |
t <- qt |
455 |
let fnexp = stringE fname |
456 |
fvare = varE fvar |
457 |
(if isOptional t |
458 |
then [| case $fvare of |
459 |
Just v' -> [( $fnexp, $showJSONE v')] |
460 |
Nothing -> [] |
461 |
|] |
462 |
else [| [( $fnexp, $showJSONE $fvare )] |]) |
463 |
|
464 |
-- | Generates the \"save\" clause for an entire opcode constructor. |
465 |
-- |
466 |
-- This matches the opcode with variables named the same as the |
467 |
-- constructor fields (just so that the spliced in code looks nicer), |
468 |
-- and passes those name plus the parameter definition to 'saveField'. |
469 |
saveConstructor :: String -- ^ The constructor name |
470 |
-> [OpParam] -- ^ The parameter definitions for this |
471 |
-- constructor |
472 |
-> Q Clause -- ^ Resulting clause |
473 |
saveConstructor sname fields = do |
474 |
let cname = mkName sname |
475 |
let fnames = map (\(n, _, _) -> mkName n) fields |
476 |
let pat = conP cname (map varP fnames) |
477 |
let felems = map (uncurry saveField) (zip fnames fields) |
478 |
-- now build the OP_ID serialisation |
479 |
opid = [| [( $(stringE "OP_ID"), |
480 |
$showJSONE $(stringE . deCamelCase $ sname) )] |] |
481 |
flist = listE (opid:felems) |
482 |
-- and finally convert all this to a json object |
483 |
flist' = [| $(varNameE "makeObj") (concat $flist) |] |
484 |
clause [pat] (normalB flist') [] |
485 |
|
486 |
-- | Generates the main save opcode function. |
487 |
-- |
488 |
-- This builds a per-constructor match clause that contains the |
489 |
-- respective constructor-serialisation code. |
490 |
genSaveOpCode :: [(String, [OpParam])] -> Q (Dec, Dec) |
491 |
genSaveOpCode opdefs = do |
492 |
cclauses <- mapM (uncurry saveConstructor) opdefs |
493 |
let fname = mkName "saveOpCode" |
494 |
sigt <- [t| $(conT (mkName "OpCode")) -> JSON.JSValue |] |
495 |
return $ (SigD fname sigt, FunD fname cclauses) |
496 |
|
497 |
-- | Generates the \"load\" field for a single parameter. |
498 |
-- |
499 |
-- There is custom handling, depending on how the parameter is |
500 |
-- specified. For a 'Maybe' type parameter, we allow that it is not |
501 |
-- present (via 'Utils.maybeFromObj'). Otherwise, if there is a |
502 |
-- default value, we allow the parameter to be abset, and finally if |
503 |
-- there is no default value, we require its presence. |
504 |
loadField :: OpParam -> Q (Name, Stmt) |
505 |
loadField (fname, qt, qdefa) = do |
506 |
let fvar = mkName fname |
507 |
t <- qt |
508 |
defa <- qdefa |
509 |
-- these are used in all patterns below |
510 |
let objvar = varNameE "o" |
511 |
objfield = stringE fname |
512 |
bexp <- if isOptional t |
513 |
then [| $((varNameE "maybeFromObj")) $objvar $objfield |] |
514 |
else case defa of |
515 |
AppE (ConE dt) defval | dt == 'Just -> |
516 |
-- but has a default value |
517 |
[| $(varNameE "fromObjWithDefault") |
518 |
$objvar $objfield $(return defval) |] |
519 |
ConE dt | dt == 'Nothing -> |
520 |
[| $(varNameE "fromObj") $objvar $objfield |] |
521 |
s -> fail $ "Invalid default value " ++ show s ++ |
522 |
", expecting either 'Nothing' or a 'Just defval'" |
523 |
return (fvar, BindS (VarP fvar) bexp) |
524 |
|
525 |
loadConstructor :: String -> [OpParam] -> Q Exp |
526 |
loadConstructor sname fields = do |
527 |
let name = mkName sname |
528 |
fbinds <- mapM loadField fields |
529 |
let (fnames, fstmts) = unzip fbinds |
530 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
531 |
fstmts' = fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
532 |
return $ DoE fstmts' |
533 |
|
534 |
genLoadOpCode :: [(String, [OpParam])] -> Q (Dec, Dec) |
535 |
genLoadOpCode opdefs = do |
536 |
let fname = mkName "loadOpCode" |
537 |
arg1 = mkName "v" |
538 |
objname = mkName "o" |
539 |
opid = mkName "op_id" |
540 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
541 |
(JSON.readJSON $(varE arg1)) |] |
542 |
st2 <- bindS (varP opid) [| $(varNameE "fromObj") |
543 |
$(varE objname) $(stringE "OP_ID") |] |
544 |
-- the match results (per-constructor blocks) |
545 |
mexps <- mapM (uncurry loadConstructor) opdefs |
546 |
fails <- [| fail $ "Unknown opcode " ++ $(varE opid) |] |
547 |
let mpats = map (\(me, c) -> |
548 |
let mp = LitP . StringL . deCamelCase . fst $ c |
549 |
in Match mp (NormalB me) [] |
550 |
) $ zip mexps opdefs |
551 |
defmatch = Match WildP (NormalB fails) [] |
552 |
cst = NoBindS $ CaseE (VarE opid) $ mpats++[defmatch] |
553 |
body = DoE [st1, st2, cst] |
554 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT (mkName "OpCode")) |] |
555 |
return $ (SigD fname sigt, FunD fname [Clause [VarP arg1] (NormalB body) []]) |
556 |
|
557 |
-- | No default type. |
558 |
noDefault :: Q Exp |
559 |
noDefault = conE 'Nothing |
560 |
|
561 |
-- * Template code for luxi |
562 |
|
563 |
-- | Constructor-to-string for LuxiOp. |
564 |
genStrOfOp :: Name -> String -> Q [Dec] |
565 |
genStrOfOp = genConstrToStr id |
566 |
|
567 |
-- | Constructor-to-string for MsgKeys. |
568 |
genStrOfKey :: Name -> String -> Q [Dec] |
569 |
genStrOfKey = genConstrToStr ensureLower |
570 |
|
571 |
-- | LuxiOp parameter type. |
572 |
type LuxiParam = (String, Q Type, Q Exp) |
573 |
|
574 |
-- | Generates the LuxiOp data type. |
575 |
-- |
576 |
-- This takes a Luxi operation definition and builds both the |
577 |
-- datatype and the function trnasforming the arguments to JSON. |
578 |
-- We can't use anything less generic, because the way different |
579 |
-- operations are serialized differs on both parameter- and top-level. |
580 |
-- |
581 |
-- There are three things to be defined for each parameter: |
582 |
-- |
583 |
-- * name |
584 |
-- |
585 |
-- * type |
586 |
-- |
587 |
-- * operation; this is the operation performed on the parameter before |
588 |
-- serialization |
589 |
-- |
590 |
genLuxiOp :: String -> [(String, [LuxiParam])] -> Q [Dec] |
591 |
genLuxiOp name cons = do |
592 |
decl_d <- mapM (\(cname, fields) -> do |
593 |
fields' <- mapM (\(_, qt, _) -> |
594 |
qt >>= \t -> return (NotStrict, t)) |
595 |
fields |
596 |
return $ NormalC (mkName cname) fields') |
597 |
cons |
598 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Read] |
599 |
(savesig, savefn) <- genSaveLuxiOp cons |
600 |
return [declD, savesig, savefn] |
601 |
|
602 |
-- | Generates the \"save\" expression for a single luxi parameter. |
603 |
saveLuxiField :: Name -> LuxiParam -> Q Exp |
604 |
saveLuxiField fvar (_, qt, fn) = |
605 |
[| JSON.showJSON ( $(liftM2 appFn fn $ varE fvar) ) |] |
606 |
|
607 |
-- | Generates the \"save\" clause for entire LuxiOp constructor. |
608 |
saveLuxiConstructor :: (String, [LuxiParam]) -> Q Clause |
609 |
saveLuxiConstructor (sname, fields) = do |
610 |
let cname = mkName sname |
611 |
fnames = map (\(nm, _, _) -> mkName nm) fields |
612 |
pat = conP cname (map varP fnames) |
613 |
flist = map (uncurry saveLuxiField) (zip fnames fields) |
614 |
finval = if null flist |
615 |
then [| JSON.showJSON () |] |
616 |
else [| JSON.showJSON $(listE flist) |] |
617 |
clause [pat] (normalB finval) [] |
618 |
|
619 |
-- | Generates the main save LuxiOp function. |
620 |
genSaveLuxiOp :: [(String, [LuxiParam])]-> Q (Dec, Dec) |
621 |
genSaveLuxiOp opdefs = do |
622 |
sigt <- [t| $(conT (mkName "LuxiOp")) -> JSON.JSValue |] |
623 |
let fname = mkName "opToArgs" |
624 |
cclauses <- mapM saveLuxiConstructor opdefs |
625 |
return $ (SigD fname sigt, FunD fname cclauses) |
626 |
|
627 |
-- * "Objects" functionality |
628 |
|
629 |
-- | Extract the field's declaration from a Field structure. |
630 |
fieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
631 |
fieldTypeInfo field_pfx fd = do |
632 |
t <- actualFieldType fd |
633 |
let n = mkName . (field_pfx ++) . fieldRecordName $ fd |
634 |
return (n, NotStrict, t) |
635 |
|
636 |
-- | Build an object declaration. |
637 |
buildObject :: String -> String -> [Field] -> Q [Dec] |
638 |
buildObject sname field_pfx fields = do |
639 |
let name = mkName sname |
640 |
fields_d <- mapM (fieldTypeInfo field_pfx) fields |
641 |
let decl_d = RecC name fields_d |
642 |
let declD = DataD [] name [] [decl_d] [''Show, ''Read] |
643 |
ser_decls <- buildObjectSerialisation sname fields |
644 |
return $ declD:ser_decls |
645 |
|
646 |
buildObjectSerialisation :: String -> [Field] -> Q [Dec] |
647 |
buildObjectSerialisation sname fields = do |
648 |
let name = mkName sname |
649 |
savedecls <- genSaveObject saveObjectField sname fields |
650 |
(loadsig, loadfn) <- genLoadObject loadObjectField sname fields |
651 |
shjson <- objectShowJSON sname |
652 |
rdjson <- objectReadJSON sname |
653 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
654 |
(rdjson:shjson) |
655 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
656 |
|
657 |
genSaveObject :: (Name -> Field -> Q Exp) |
658 |
-> String -> [Field] -> Q [Dec] |
659 |
genSaveObject save_fn sname fields = do |
660 |
let name = mkName sname |
661 |
let fnames = map (mkName . fieldVariable) fields |
662 |
let pat = conP name (map varP fnames) |
663 |
let tdname = mkName ("toDict" ++ sname) |
664 |
tdsigt <- [t| $(conT name) -> [(String, JSON.JSValue)] |] |
665 |
|
666 |
let felems = map (uncurry save_fn) (zip fnames fields) |
667 |
flist = listE felems |
668 |
-- and finally convert all this to a json object |
669 |
tdlist = [| concat $flist |] |
670 |
iname = mkName "i" |
671 |
tclause <- clause [pat] (normalB tdlist) [] |
672 |
cclause <- [| $(varNameE "makeObj") . $(varE tdname) |] |
673 |
let fname = mkName ("save" ++ sname) |
674 |
sigt <- [t| $(conT name) -> JSON.JSValue |] |
675 |
return [SigD tdname tdsigt, FunD tdname [tclause], |
676 |
SigD fname sigt, ValD (VarP fname) (NormalB cclause) []] |
677 |
|
678 |
saveObjectField :: Name -> Field -> Q Exp |
679 |
saveObjectField fvar field |
680 |
| isContainer = [| [( $nameE , $showJSONE . showContainer $ $fvarE)] |] |
681 |
| fisOptional = [| case $(varE fvar) of |
682 |
Nothing -> [] |
683 |
Just v -> [( $nameE, $showJSONE v)] |
684 |
|] |
685 |
| otherwise = case fieldShow field of |
686 |
Nothing -> [| [( $nameE, $showJSONE $fvarE)] |] |
687 |
Just fn -> [| [( $nameE, $showJSONE . $fn $ $fvarE)] |] |
688 |
where isContainer = fieldIsContainer field |
689 |
fisOptional = fieldIsOptional field |
690 |
nameE = stringE (fieldName field) |
691 |
fvarE = varE fvar |
692 |
|
693 |
objectShowJSON :: String -> Q [Dec] |
694 |
objectShowJSON name = |
695 |
[d| showJSON = JSON.showJSON . $(varE . mkName $ "save" ++ name) |] |
696 |
|
697 |
genLoadObject :: (Field -> Q (Name, Stmt)) |
698 |
-> String -> [Field] -> Q (Dec, Dec) |
699 |
genLoadObject load_fn sname fields = do |
700 |
let name = mkName sname |
701 |
funname = mkName $ "load" ++ sname |
702 |
arg1 = mkName "v" |
703 |
objname = mkName "o" |
704 |
opid = mkName "op_id" |
705 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
706 |
(JSON.readJSON $(varE arg1)) |] |
707 |
fbinds <- mapM load_fn fields |
708 |
let (fnames, fstmts) = unzip fbinds |
709 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
710 |
fstmts' = st1:fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
711 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT name) |] |
712 |
return $ (SigD funname sigt, |
713 |
FunD funname [Clause [VarP arg1] (NormalB (DoE fstmts')) []]) |
714 |
|
715 |
loadObjectField :: Field -> Q (Name, Stmt) |
716 |
loadObjectField field = do |
717 |
let name = fieldVariable field |
718 |
fvar = mkName name |
719 |
-- these are used in all patterns below |
720 |
let objvar = varNameE "o" |
721 |
objfield = stringE (fieldName field) |
722 |
loadexp = |
723 |
if fieldIsOptional field |
724 |
then [| $(varNameE "maybeFromObj") $objvar $objfield |] |
725 |
else case fieldDefault field of |
726 |
Just defv -> |
727 |
[| $(varNameE "fromObjWithDefault") $objvar |
728 |
$objfield $defv |] |
729 |
Nothing -> [| $(varNameE "fromObj") $objvar $objfield |] |
730 |
bexp <- loadFn field loadexp |
731 |
|
732 |
return (fvar, BindS (VarP fvar) bexp) |
733 |
|
734 |
objectReadJSON :: String -> Q Dec |
735 |
objectReadJSON name = do |
736 |
let s = mkName "s" |
737 |
body <- [| case JSON.readJSON $(varE s) of |
738 |
JSON.Ok s' -> $(varE .mkName $ "load" ++ name) s' |
739 |
JSON.Error e -> |
740 |
JSON.Error $ "Can't parse value for type " ++ |
741 |
$(stringE name) ++ ": " ++ e |
742 |
|] |
743 |
return $ FunD (mkName "readJSON") [Clause [VarP s] (NormalB body) []] |
744 |
|
745 |
-- * Inheritable parameter tables implementation |
746 |
|
747 |
-- | Compute parameter type names. |
748 |
paramTypeNames :: String -> (String, String) |
749 |
paramTypeNames root = ("Filled" ++ root ++ "Params", |
750 |
"Partial" ++ root ++ "Params") |
751 |
|
752 |
-- | Compute information about the type of a parameter field. |
753 |
paramFieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
754 |
paramFieldTypeInfo field_pfx fd = do |
755 |
t <- actualFieldType fd |
756 |
let n = mkName . (++ "P") . (field_pfx ++) . |
757 |
fieldRecordName $ fd |
758 |
return (n, NotStrict, AppT (ConT ''Maybe) t) |
759 |
|
760 |
-- | Build a parameter declaration. |
761 |
-- |
762 |
-- This function builds two different data structures: a /filled/ one, |
763 |
-- in which all fields are required, and a /partial/ one, in which all |
764 |
-- fields are optional. Due to the current record syntax issues, the |
765 |
-- fields need to be named differrently for the two structures, so the |
766 |
-- partial ones get a /P/ suffix. |
767 |
buildParam :: String -> String -> [Field] -> Q [Dec] |
768 |
buildParam sname field_pfx fields = do |
769 |
let (sname_f, sname_p) = paramTypeNames sname |
770 |
name_f = mkName sname_f |
771 |
name_p = mkName sname_p |
772 |
fields_f <- mapM (fieldTypeInfo field_pfx) fields |
773 |
fields_p <- mapM (paramFieldTypeInfo field_pfx) fields |
774 |
let decl_f = RecC name_f fields_f |
775 |
decl_p = RecC name_p fields_p |
776 |
let declF = DataD [] name_f [] [decl_f] [''Show, ''Read] |
777 |
declP = DataD [] name_p [] [decl_p] [''Show, ''Read] |
778 |
ser_decls_f <- buildObjectSerialisation sname_f fields |
779 |
ser_decls_p <- buildPParamSerialisation sname_p fields |
780 |
fill_decls <- fillParam sname field_pfx fields |
781 |
return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls |
782 |
|
783 |
buildPParamSerialisation :: String -> [Field] -> Q [Dec] |
784 |
buildPParamSerialisation sname fields = do |
785 |
let name = mkName sname |
786 |
savedecls <- genSaveObject savePParamField sname fields |
787 |
(loadsig, loadfn) <- genLoadObject loadPParamField sname fields |
788 |
shjson <- objectShowJSON sname |
789 |
rdjson <- objectReadJSON sname |
790 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
791 |
(rdjson:shjson) |
792 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
793 |
|
794 |
savePParamField :: Name -> Field -> Q Exp |
795 |
savePParamField fvar field = do |
796 |
checkNonOptDef field |
797 |
let actualVal = mkName "v" |
798 |
normalexpr <- saveObjectField actualVal field |
799 |
-- we have to construct the block here manually, because we can't |
800 |
-- splice-in-splice |
801 |
return $ CaseE (VarE fvar) [ Match (ConP 'Nothing []) |
802 |
(NormalB (ConE '[])) [] |
803 |
, Match (ConP 'Just [VarP actualVal]) |
804 |
(NormalB normalexpr) [] |
805 |
] |
806 |
loadPParamField :: Field -> Q (Name, Stmt) |
807 |
loadPParamField field = do |
808 |
checkNonOptDef field |
809 |
let name = fieldName field |
810 |
fvar = mkName name |
811 |
-- these are used in all patterns below |
812 |
let objvar = varNameE "o" |
813 |
objfield = stringE name |
814 |
loadexp = [| $(varNameE "maybeFromObj") $objvar $objfield |] |
815 |
bexp <- loadFn field loadexp |
816 |
return (fvar, BindS (VarP fvar) bexp) |
817 |
|
818 |
-- | Builds a simple declaration of type @n_x = fromMaybe f_x p_x@. |
819 |
buildFromMaybe :: String -> Q Dec |
820 |
buildFromMaybe fname = |
821 |
valD (varP (mkName $ "n_" ++ fname)) |
822 |
(normalB [| $(varNameE "fromMaybe") |
823 |
$(varNameE $ "f_" ++ fname) |
824 |
$(varNameE $ "p_" ++ fname) |]) [] |
825 |
|
826 |
fillParam :: String -> String -> [Field] -> Q [Dec] |
827 |
fillParam sname field_pfx fields = do |
828 |
let fnames = map (\fd -> field_pfx ++ fieldRecordName fd) fields |
829 |
(sname_f, sname_p) = paramTypeNames sname |
830 |
oname_f = "fobj" |
831 |
oname_p = "pobj" |
832 |
name_f = mkName sname_f |
833 |
name_p = mkName sname_p |
834 |
fun_name = mkName $ "fill" ++ sname ++ "Params" |
835 |
le_full = ValD (ConP name_f (map (VarP . mkName . ("f_" ++)) fnames)) |
836 |
(NormalB . VarE . mkName $ oname_f) [] |
837 |
le_part = ValD (ConP name_p (map (VarP . mkName . ("p_" ++)) fnames)) |
838 |
(NormalB . VarE . mkName $ oname_p) [] |
839 |
obj_new = foldl (\accu vname -> AppE accu (VarE vname)) (ConE name_f) |
840 |
$ map (mkName . ("n_" ++)) fnames |
841 |
le_new <- mapM buildFromMaybe fnames |
842 |
funt <- [t| $(conT name_f) -> $(conT name_p) -> $(conT name_f) |] |
843 |
let sig = SigD fun_name funt |
844 |
fclause = Clause [VarP (mkName oname_f), VarP (mkName oname_p)] |
845 |
(NormalB $ LetE (le_full:le_part:le_new) obj_new) [] |
846 |
fun = FunD fun_name [fclause] |
847 |
return [sig, fun] |