ghc/compiler/main/CmdLineOpts.lhs

   1 %
   2 % (c) The University of Glasgow, 1996-2000
   3 %
   4 \section[CmdLineOpts]{Things to do with command-line options}
   5
   6 \begin{code}
   7
   8 module CmdLineOpts (
   9         CoreToDo(..),
  10         SimplifierSwitch(..), isAmongSimpl,
  11         StgToDo(..),
  12         SwitchResult(..),
  13         HscLang(..),
  14         DynFlag(..),    -- needed non-abstractly by DriverFlags
  15         DynFlags(..),
  16
  17         v_Static_hsc_opts,
  18
  19         intSwitchSet,
  20         switchIsOn,
  21         isStaticHscFlag,
  22
  23         opt_PprStyle_NoPrags,
  24         opt_PprStyle_RawTypes,
  25         opt_PprUserLength,
  26         opt_PprStyle_Debug,
  27
  28         dopt,
  29
  30         -- other dynamic flags
  31         dopt_CoreToDo,
  32         dopt_StgToDo,
  33         dopt_HscLang,
  34         dopt_OutName,
  35
  36         -- profiling opts
  37         opt_AutoSccsOnAllToplevs,
  38         opt_AutoSccsOnExportedToplevs,
  39         opt_AutoSccsOnIndividualCafs,
  40         opt_AutoSccsOnDicts,
  41         opt_SccProfilingOn,
  42         opt_DoTickyProfiling,
  43
  44         -- language opts
  45         opt_AllStrict,
  46         opt_DictsStrict,
  47         opt_MaxContextReductionDepth,
  48         opt_IrrefutableTuples,
  49         opt_NumbersStrict,
  50         opt_Parallel,
  51         opt_SMP,
  52
  53         -- optimisation opts
  54         opt_DoSemiTagging,
  55         opt_FoldrBuildOn,
  56         opt_LiberateCaseThreshold,
  57         opt_StgDoLetNoEscapes,
  58         opt_UnfoldCasms,
  59         opt_UsageSPOn,
  60         opt_UnboxStrictFields,
  61         opt_SimplNoPreInlining,
  62         opt_SimplDoEtaReduction,
  63         opt_SimplDoLambdaEtaExpansion,
  64         opt_SimplCaseOfCase,
  65         opt_SimplCaseMerge,
  66         opt_SimplPedanticBottoms,
  67         opt_SimplExcessPrecision,
  68
  69         -- Unfolding control
  70         opt_UF_HiFileThreshold,
  71         opt_UF_CreationThreshold,
  72         opt_UF_UseThreshold,
  73         opt_UF_FunAppDiscount,
  74         opt_UF_KeenessFactor,
  75         opt_UF_UpdateInPlace,
  76         opt_UF_CheapOp,
  77         opt_UF_DearOp,
  78
  79         -- misc opts
  80         opt_InPackage,
  81         opt_EmitCExternDecls,
  82         opt_EnsureSplittableC,
  83         opt_GranMacros,
  84         opt_HiVersion,
  85         opt_HistorySize,
  86         opt_IgnoreAsserts,
  87         opt_IgnoreIfacePragmas,
  88         opt_NoHiCheck,
  89         opt_OmitBlackHoling,
  90         opt_OmitInterfacePragmas,
  91         opt_NoPruneTyDecls,
  92         opt_NoPruneDecls,
  93         opt_Static,
  94         opt_Unregisterised,
  95         opt_Verbose
  96     ) where
  97
  98 #include "HsVersions.h"
  99
 100 import Array    ( array, (//) )
 101 import GlaExts
 102 import IOExts   ( IORef, readIORef )
 103 import Constants        -- Default values for some flags
 104 import Util
 105 import FastTypes
 106
 107 import Maybes           ( firstJust )
 108 import Panic            ( panic )
 109
 110 #if __GLASGOW_HASKELL__ < 301
 111 import ArrBase  ( Array(..) )
 112 #else
 113 import PrelArr  ( Array(..) )
 114 #endif
 115 \end{code}
 116
 117 %************************************************************************
 118 %*                                                                      *
 119 \subsection{Command-line options}
 120 %*                                                                      *
 121 %************************************************************************
 122
 123 The hsc command-line options are split into two categories:
 124
 125   - static flags
 126   - dynamic flags
 127
 128 Static flags are represented by top-level values of type Bool or Int,
 129 for example.  They therefore have the same value throughout the
 130 invocation of hsc.
 131
 132 Dynamic flags are represented by an abstract type, DynFlags, which is
 133 passed into hsc by the compilation manager for every compilation.
 134 Dynamic flags are those that change on a per-compilation basis,
 135 perhaps because they may be present in the OPTIONS pragma at the top
 136 of a module.
 137
 138 Other flag-related blurb:
 139
 140 A list of {\em ToDo}s is things to be done in a particular part of
 141 processing.  A (fictitious) example for the Core-to-Core simplifier
 142 might be: run the simplifier, then run the strictness analyser, then
 143 run the simplifier again (three ``todos'').
 144
 145 There are three ``to-do processing centers'' at the moment.  In the
 146 main loop (\tr{main/Main.lhs}), in the Core-to-Core processing loop
 147 (\tr{simplCore/SimplCore.lhs), and in the STG-to-STG processing loop
 148 (\tr{simplStg/SimplStg.lhs}).
 149
 150 %************************************************************************
 151 %*                                                                      *
 152 \subsection{Datatypes associated with command-line options}
 153 %*                                                                      *
 154 %************************************************************************
 155
 156 \begin{code}
 157 data SwitchResult
 158   = SwBool      Bool            -- on/off
 159   | SwString    FAST_STRING     -- nothing or a String
 160   | SwInt       Int             -- nothing or an Int
 161 \end{code}
 162
 163 \begin{code}
 164 data CoreToDo           -- These are diff core-to-core passes,
 165                         -- which may be invoked in any order,
 166                         -- as many times as you like.
 167
 168   = CoreDoSimplify      -- The core-to-core simplifier.
 169         (SimplifierSwitch -> SwitchResult)
 170                         -- Each run of the simplifier can take a different
 171                         -- set of simplifier-specific flags.
 172   | CoreDoFloatInwards
 173   | CoreDoFloatOutwards Bool    -- True <=> float lambdas to top level
 174   | CoreLiberateCase
 175   | CoreDoPrintCore
 176   | CoreDoStaticArgs
 177   | CoreDoStrictness
 178   | CoreDoWorkerWrapper
 179   | CoreDoSpecialising
 180   | CoreDoUSPInf
 181   | CoreDoCPResult
 182   | CoreDoGlomBinds
 183   | CoreCSE
 184
 185   | CoreDoNothing        -- useful when building up lists of these things
 186 \end{code}
 187
 188 \begin{code}
 189 data StgToDo
 190   = StgDoStaticArgs
 191   | StgDoLambdaLift
 192   | StgDoMassageForProfiling  -- should be (next to) last
 193   -- There's also setStgVarInfo, but its absolute "lastness"
 194   -- is so critical that it is hardwired in (no flag).
 195   | D_stg_stats
 196 \end{code}
 197
 198 \begin{code}
 199 data SimplifierSwitch
 200   = MaxSimplifierIterations Int
 201   | SimplInlinePhase Int
 202   | DontApplyRules
 203   | NoCaseOfCase
 204   | SimplLetToCase
 205 \end{code}
 206
 207 %************************************************************************
 208 %*                                                                      *
 209 \subsection{Dynamic command-line options}
 210 %*                                                                      *
 211 %************************************************************************
 212
 213 \begin{code}
 214 data DynFlag
 215
 216    -- debugging flags
 217    = Opt_D_dump_all
 218    | Opt_D_dump_most
 219    | Opt_D_dump_absC
 220    | Opt_D_dump_asm
 221    | Opt_D_dump_cpranal
 222    | Opt_D_dump_deriv
 223    | Opt_D_dump_ds
 224    | Opt_D_dump_flatC
 225    | Opt_D_dump_foreign
 226    | Opt_D_dump_inlinings
 227    | Opt_D_dump_occur_anal
 228    | Opt_D_dump_parsed
 229    | Opt_D_dump_realC
 230    | Opt_D_dump_rn
 231    | Opt_D_dump_simpl
 232    | Opt_D_dump_simpl_iterations
 233    | Opt_D_dump_spec
 234    | Opt_D_dump_stg
 235    | Opt_D_dump_stranal
 236    | Opt_D_dump_tc
 237    | Opt_D_dump_types
 238    | Opt_D_dump_rules
 239    | Opt_D_dump_usagesp
 240    | Opt_D_dump_cse
 241    | Opt_D_dump_worker_wrapper
 242    | Opt_D_show_passes
 243    | Opt_D_dump_rn_trace
 244    | Opt_D_dump_rn_stats
 245    | Opt_D_dump_stix
 246    | Opt_D_dump_simpl_stats
 247    | Opt_D_source_stats
 248    | Opt_D_verbose_core2core
 249    | Opt_D_verbose_stg2stg
 250    | Opt_D_dump_hi
 251    | Opt_D_dump_hi_diffs
 252    | Opt_D_dump_minimal_imports
 253    | Opt_DoCoreLinting
 254    | Opt_DoStgLinting
 255    | Opt_DoUSPLinting
 256
 257    | Opt_WarnDuplicateExports
 258    | Opt_WarnHiShadows
 259    | Opt_WarnIncompletePatterns
 260    | Opt_WarnMissingFields
 261    | Opt_WarnMissingMethods
 262    | Opt_WarnMissingSigs
 263    | Opt_WarnNameShadowing
 264    | Opt_WarnOverlappingPatterns
 265    | Opt_WarnSimplePatterns
 266    | Opt_WarnTypeDefaults
 267    | Opt_WarnUnusedBinds
 268    | Opt_WarnUnusedImports
 269    | Opt_WarnUnusedMatches
 270    | Opt_WarnDeprecations
 271
 272    -- language opts
 273    | Opt_AllowOverlappingInstances
 274    | Opt_AllowUndecidableInstances
 275    | Opt_GlasgowExts
 276    | Opt_Generics
 277    | Opt_NoImplicitPrelude
 278
 279    -- misc
 280    | Opt_ReportCompile
 281    deriving (Eq)
 282
 283 data DynFlags = DynFlags {
 284   coreToDo   :: [CoreToDo],
 285   stgToDo    :: [StgToDo],
 286   hscLang    :: HscLang,
 287   hscOutName :: String,  -- name of the file in which to place output
 288   flags      :: [DynFlag]
 289  }
 290
 291 dopt :: DynFlag -> DynFlags -> Bool
 292 dopt f dflags  = f `elem` (flags dflags)
 293
 294 dopt_CoreToDo :: DynFlags -> [CoreToDo]
 295 dopt_CoreToDo = coreToDo
 296
 297 dopt_StgToDo :: DynFlags -> [StgToDo]
 298 dopt_StgToDo = stgToDo
 299
 300 dopt_OutName :: DynFlags -> String
 301 dopt_OutName = hscOutName
 302
 303 data HscLang
 304   = HscC
 305   | HscAsm
 306   | HscJava
 307   | HscInterpreted
 308     deriving Eq
 309
 310 dopt_HscLang :: DynFlags -> HscLang
 311 dopt_HscLang = hscLang
 312 \end{code}
 313
 314 %************************************************************************
 315 %*                                                                      *
 316 \subsection{Classifying command-line options}
 317 %*                                                                      *
 318 %************************************************************************
 319
 320 \begin{code}
 321 -- v_Statis_hsc_opts is here to avoid a circular dependency with
 322 -- main/DriverState.
 323 GLOBAL_VAR(v_Static_hsc_opts, [], [String])
 324
 325 lookUp           :: FAST_STRING -> Bool
 326 lookup_int       :: String -> Maybe Int
 327 lookup_def_int   :: String -> Int -> Int
 328 lookup_def_float :: String -> Float -> Float
 329 lookup_str       :: String -> Maybe String
 330
 331 unpacked_static_opts = unsafePerformIO (readIORef v_Static_hsc_opts)
 332 packed_static_opts   = map _PK_ unpacked_static_opts
 333
 334 lookUp     sw = sw `elem` packed_static_opts
 335
 336 lookup_str sw = firstJust (map (startsWith sw) unpacked_static_opts)
 337
 338 lookup_int sw = case (lookup_str sw) of
 339                   Nothing -> Nothing
 340                   Just xx -> Just (read xx)
 341
 342 lookup_def_int sw def = case (lookup_str sw) of
 343                             Nothing -> def              -- Use default
 344                             Just xx -> read xx
 345
 346 lookup_def_float sw def = case (lookup_str sw) of
 347                             Nothing -> def              -- Use default
 348                             Just xx -> read xx
 349
 350
 351 {-
 352  Putting the compiler options into temporary at-files
 353  may turn out to be necessary later on if we turn hsc into
 354  a pure Win32 application where I think there's a command-line
 355  length limit of 255. unpacked_opts understands the @ option.
 356
 357 unpacked_opts :: [String]
 358 unpacked_opts =
 359   concat $
 360   map (expandAts) $
 361   map _UNPK_ argv  -- NOT ARGV any more: v_Static_hsc_opts
 362   where
 363    expandAts ('@':fname) = words (unsafePerformIO (readFile fname))
 364    expandAts l = [l]
 365 -}
 366 \end{code}
 367
 368 %************************************************************************
 369 %*                                                                      *
 370 \subsection{Static options}
 371 %*                                                                      *
 372 %************************************************************************
 373
 374 \begin{code}
 375 -- debugging opts
 376 opt_PprStyle_NoPrags            = lookUp  SLIT("-dppr-noprags")
 377 opt_PprStyle_Debug              = lookUp  SLIT("-dppr-debug")
 378 opt_PprStyle_RawTypes           = lookUp  SLIT("-dppr-rawtypes")
 379 opt_PprUserLength               = lookup_def_int "-dppr-user-length" 5 --ToDo: give this a name
 380
 381 -- profiling opts
 382 opt_AutoSccsOnAllToplevs        = lookUp  SLIT("-fauto-sccs-on-all-toplevs")
 383 opt_AutoSccsOnExportedToplevs   = lookUp  SLIT("-fauto-sccs-on-exported-toplevs")
 384 opt_AutoSccsOnIndividualCafs    = lookUp  SLIT("-fauto-sccs-on-individual-cafs")
 385 opt_AutoSccsOnDicts             = lookUp  SLIT("-fauto-sccs-on-dicts")
 386 opt_SccProfilingOn              = lookUp  SLIT("-fscc-profiling")
 387 opt_DoTickyProfiling            = lookUp  SLIT("-fticky-ticky")
 388
 389 -- language opts
 390 opt_AllStrict                   = lookUp  SLIT("-fall-strict")
 391 opt_DictsStrict                 = lookUp  SLIT("-fdicts-strict")
 392 opt_IrrefutableTuples           = lookUp  SLIT("-firrefutable-tuples")
 393 opt_MaxContextReductionDepth    = lookup_def_int "-fcontext-stack" mAX_CONTEXT_REDUCTION_DEPTH
 394 opt_NumbersStrict               = lookUp  SLIT("-fnumbers-strict")
 395 opt_Parallel                    = lookUp  SLIT("-fparallel")
 396 opt_SMP                         = lookUp  SLIT("-fsmp")
 397
 398 -- optimisation opts
 399 opt_DoSemiTagging               = lookUp  SLIT("-fsemi-tagging")
 400 opt_FoldrBuildOn                = lookUp  SLIT("-ffoldr-build-on")
 401 opt_LiberateCaseThreshold       = lookup_def_int "-fliberate-case-threshold" (10::Int)
 402 opt_StgDoLetNoEscapes           = lookUp  SLIT("-flet-no-escape")
 403 opt_UnfoldCasms                 = lookUp SLIT("-funfold-casms-in-hi-file")
 404 opt_UsageSPOn                   = lookUp  SLIT("-fusagesp-on")
 405 opt_UnboxStrictFields           = lookUp  SLIT("-funbox-strict-fields")
 406
 407 {-
 408    The optional '-inpackage=P' flag tells what package
 409    we are compiling this module for.
 410    The Prelude, for example is compiled with '-package prelude'
 411 -}
 412 opt_InPackage                   = case lookup_str "-inpackage=" of
 413                                     Just p  -> _PK_ p
 414                                     Nothing -> SLIT("Main")     -- The package name if none is specified
 415
 416 opt_EmitCExternDecls            = lookUp  SLIT("-femit-extern-decls")
 417 opt_EnsureSplittableC           = lookUp  SLIT("-fglobalise-toplev-names")
 418 opt_GranMacros                  = lookUp  SLIT("-fgransim")
 419 opt_HiVersion                   = lookup_def_int "-fhi-version=" 0 -- what version we're compiling.
 420 opt_HistorySize                 = lookup_def_int "-fhistory-size" 20
 421 opt_IgnoreAsserts               = lookUp  SLIT("-fignore-asserts")
 422 opt_IgnoreIfacePragmas          = lookUp  SLIT("-fignore-interface-pragmas")
 423 opt_NoHiCheck                   = lookUp  SLIT("-fno-hi-version-check")
 424 opt_OmitBlackHoling             = lookUp  SLIT("-dno-black-holing")
 425 opt_OmitInterfacePragmas        = lookUp  SLIT("-fomit-interface-pragmas")
 426
 427 -- Simplifier switches
 428 opt_SimplNoPreInlining          = lookUp SLIT("-fno-pre-inlining")
 429         -- NoPreInlining is there just to see how bad things
 430         -- get if you don't do it!
 431 opt_SimplDoEtaReduction         = lookUp SLIT("-fdo-eta-reduction")
 432 opt_SimplDoLambdaEtaExpansion   = lookUp SLIT("-fdo-lambda-eta-expansion")
 433 opt_SimplCaseOfCase             = lookUp SLIT("-fcase-of-case")
 434 opt_SimplCaseMerge              = lookUp SLIT("-fcase-merge")
 435 opt_SimplPedanticBottoms        = lookUp SLIT("-fpedantic-bottoms")
 436 opt_SimplExcessPrecision        = lookUp SLIT("-fexcess-precision")
 437
 438 -- Unfolding control
 439 opt_UF_HiFileThreshold          = lookup_def_int "-funfolding-interface-threshold" (45::Int)
 440 opt_UF_CreationThreshold        = lookup_def_int "-funfolding-creation-threshold"  (45::Int)
 441 opt_UF_UseThreshold             = lookup_def_int "-funfolding-use-threshold"       (8::Int)     -- Discounts can be big
 442 opt_UF_FunAppDiscount           = lookup_def_int "-funfolding-fun-discount"        (6::Int)     -- It's great to inline a fn
 443 opt_UF_KeenessFactor            = lookup_def_float "-funfolding-keeness-factor"    (1.5::Float)
 444 opt_UF_UpdateInPlace            = lookUp  SLIT("-funfolding-update-in-place")
 445
 446 opt_UF_CheapOp  = ( 1 :: Int)   -- Only one instruction; and the args are charged for
 447 opt_UF_DearOp   = ( 4 :: Int)
 448
 449 opt_NoPruneDecls                = lookUp SLIT("-fno-prune-decls")
 450 opt_NoPruneTyDecls              = lookUp SLIT("-fno-prune-tydecls")
 451 opt_Static                      = lookUp SLIT("-static")
 452 opt_Unregisterised              = lookUp SLIT("-funregisterised")
 453 opt_Verbose                     = lookUp SLIT("-v")
 454 \end{code}
 455
 456 %************************************************************************
 457 %*                                                                      *
 458 \subsection{List of static hsc flags}
 459 %*                                                                      *
 460 %************************************************************************
 461
 462 \begin{code}
 463 isStaticHscFlag f =
 464   f `elem` [
 465         "fauto-sccs-on-all-toplevs",
 466         "fauto-sccs-on-exported-toplevs",
 467         "fauto-sccs-on-individual-cafs",
 468         "fauto-sccs-on-dicts",
 469         "fscc-profiling",
 470         "fticky-ticky",
 471         "fall-strict",
 472         "fdicts-strict",
 473         "firrefutable-tuples",
 474         "fnumbers-strict",
 475         "fparallel",
 476         "fsmp",
 477         "fsemi-tagging",
 478         "ffoldr-build-on",
 479         "flet-no-escape",
 480         "funfold-casms-in-hi-file",
 481         "fusagesp-on",
 482         "funbox-strict-fields",
 483         "femit-extern-decls",
 484         "fglobalise-toplev-names",
 485         "fgransim",
 486         "fignore-asserts",
 487         "fignore-interface-pragmas",
 488         "fno-hi-version-check",
 489         "fno-implicit-prelude",
 490         "dno-black-holing",
 491         "fomit-interface-pragmas",
 492         "fno-pre-inlining",
 493         "fdo-eta-reduction",
 494         "fdo-lambda-eta-expansion",
 495         "fcase-of-case",
 496         "fcase-merge",
 497         "fpedantic-bottoms",
 498         "fexcess-precision",
 499         "funfolding-update-in-place",
 500         "freport-compile",
 501         "fno-prune-decls",
 502         "fno-prune-tydecls",
 503         "static",
 504         "funregisterised",
 505         "v" ]
 506   || any (flip prefixMatch f) [
 507         "fcontext-stack",
 508         "fliberate-case-threshold",
 509         "fhi-version=",
 510         "fhistory-size",
 511         "funfolding-interface-threshold",
 512         "funfolding-creation-threshold",
 513         "funfolding-use-threshold",
 514         "funfolding-fun-discount",
 515         "funfolding-keeness-factor"
 516      ]
 517 \end{code}
 518
 519 %************************************************************************
 520 %*                                                                      *
 521 \subsection{Switch ordering}
 522 %*                                                                      *
 523 %************************************************************************
 524
 525 These things behave just like enumeration types.
 526
 527 \begin{code}
 528 instance Eq SimplifierSwitch where
 529     a == b = tagOf_SimplSwitch a ==# tagOf_SimplSwitch b
 530
 531 instance Ord SimplifierSwitch where
 532     a <  b  = tagOf_SimplSwitch a <# tagOf_SimplSwitch b
 533     a <= b  = tagOf_SimplSwitch a <=# tagOf_SimplSwitch b
 534
 535
 536 tagOf_SimplSwitch (SimplInlinePhase _)          = _ILIT(1)
 537 tagOf_SimplSwitch (MaxSimplifierIterations _)   = _ILIT(2)
 538 tagOf_SimplSwitch DontApplyRules                = _ILIT(3)
 539 tagOf_SimplSwitch SimplLetToCase                = _ILIT(4)
 540 tagOf_SimplSwitch NoCaseOfCase                  = _ILIT(5)
 541
 542 -- If you add anything here, be sure to change lAST_SIMPL_SWITCH_TAG, too!
 543
 544 lAST_SIMPL_SWITCH_TAG = 5
 545 \end{code}
 546
 547 %************************************************************************
 548 %*                                                                      *
 549 \subsection{Switch lookup}
 550 %*                                                                      *
 551 %************************************************************************
 552
 553 \begin{code}
 554 isAmongSimpl :: [SimplifierSwitch] -> SimplifierSwitch -> SwitchResult
 555 isAmongSimpl on_switches                -- Switches mentioned later occur *earlier*
 556                                         -- in the list; defaults right at the end.
 557   = let
 558         tidied_on_switches = foldl rm_dups [] on_switches
 559                 -- The fold*l* ensures that we keep the latest switches;
 560                 -- ie the ones that occur earliest in the list.
 561
 562         sw_tbl :: Array Int SwitchResult
 563         sw_tbl = (array (0, lAST_SIMPL_SWITCH_TAG) -- bounds...
 564                         all_undefined)
 565                  // defined_elems
 566
 567         all_undefined = [ (i, SwBool False) | i <- [0 .. lAST_SIMPL_SWITCH_TAG ] ]
 568
 569         defined_elems = map mk_assoc_elem tidied_on_switches
 570     in
 571     -- (avoid some unboxing, bounds checking, and other horrible things:)
 572 #if __GLASGOW_HASKELL__ < 405
 573     case sw_tbl of { Array bounds_who_needs_'em stuff ->
 574 #else
 575     case sw_tbl of { Array _ _ stuff ->
 576 #endif
 577     \ switch ->
 578         case (indexArray# stuff (tagOf_SimplSwitch switch)) of
 579 #if __GLASGOW_HASKELL__ < 400
 580           Lift v -> v
 581 #elif __GLASGOW_HASKELL__ < 403
 582           (# _, v #) -> v
 583 #else
 584           (# v #) -> v
 585 #endif
 586     }
 587   where
 588     mk_assoc_elem k@(MaxSimplifierIterations lvl)
 589         = (iBox (tagOf_SimplSwitch k), SwInt lvl)
 590     mk_assoc_elem k@(SimplInlinePhase n)
 591         = (iBox (tagOf_SimplSwitch k), SwInt n)
 592     mk_assoc_elem k
 593         = (iBox (tagOf_SimplSwitch k), SwBool True) -- I'm here, Mom!
 594
 595     -- cannot have duplicates if we are going to use the array thing
 596     rm_dups switches_so_far switch
 597       = if switch `is_elem` switches_so_far
 598         then switches_so_far
 599         else switch : switches_so_far
 600       where
 601         sw `is_elem` []     = False
 602         sw `is_elem` (s:ss) = (tagOf_SimplSwitch sw) ==# (tagOf_SimplSwitch s)
 603                             || sw `is_elem` ss
 604 \end{code}
 605
 606
 607 %************************************************************************
 608 %*                                                                      *
 609 \subsection{Misc functions for command-line options}
 610 %*                                                                      *
 611 %************************************************************************
 612
 613
 614 \begin{code}
 615 switchIsOn :: (switch -> SwitchResult) -> switch -> Bool
 616
 617 switchIsOn lookup_fn switch
 618   = case (lookup_fn switch) of
 619       SwBool False -> False
 620       _            -> True
 621
 622 intSwitchSet :: (switch -> SwitchResult)
 623              -> (Int -> switch)
 624              -> Maybe Int
 625
 626 intSwitchSet lookup_fn switch
 627   = case (lookup_fn (switch (panic "intSwitchSet"))) of
 628       SwInt int -> Just int
 629       _         -> Nothing
 630 \end{code}
 631
 632 \begin{code}
 633 startsWith :: String -> String -> Maybe String
 634 -- startsWith pfx (pfx++rest) = Just rest
 635
 636 startsWith []     str = Just str
 637 startsWith (c:cs) (s:ss)
 638   = if c /= s then Nothing else startsWith cs ss
 639 startsWith  _     []  = Nothing
 640
 641 endsWith  :: String -> String -> Maybe String
 642 endsWith cs ss
 643   = case (startsWith (reverse cs) (reverse ss)) of
 644       Nothing -> Nothing
 645       Just rs -> Just (reverse rs)
 646 \end{code}