Agda.TypeChecking.CompiledClause.Compile

Documentation

compileClauses

Arguments

:: Maybe (QName, Type)

Translate record patterns and coverage check with given type?

-> [Clause]

-> TCM CompiledClauses

Process function clauses into case tree. This involves: 1. Coverage checking, generating a split tree. 2. Translation of lhs record patterns into rhs uses of projection. Update the split tree. 3. Generating a case tree from the split tree. Phases 1. and 2. are skipped if Nothing.

data Cl

Stripped-down version of Clause used in clause compiler.

Constructors

Cl

Fields

• clPats :: [Arg Pattern]
• clBody :: ClauseBody

Instances

Show Cl

Methods

showsPrec :: Int -> Cl -> ShowS

show :: Cl -> String

showList :: [Cl] -> ShowS

Pretty Cl

Methods

pretty :: Cl -> Doc

prettyPrec :: Int -> Cl -> Doc

type Cls = [Cl]

compileWithSplitTree :: (Term -> Term) -> SplitTree -> Cls -> CompiledClauses

compile :: (Term -> Term) -> Cls -> CompiledClauses

nextSplit :: Cls -> Maybe (Bool, Arg Int)

Get the index of the next argument we need to split on. This the number of the first pattern that does a match in the first clause.

properSplit :: Pattern -> Maybe Bool

Is is not a variable pattern? And if yes, is it a record pattern?

isVar :: Pattern -> Bool

Is this a variable pattern?

Maintain invariant: isVar = isNothing . properSplit!

splitOn :: Bool -> Int -> Cls -> Case Cls

splitOn single n cs will force expansion of catch-alls if single.

splitC :: Int -> Cl -> Case Cl

expandCatchAlls :: Bool -> Int -> Cls -> Cls

Expand catch-alls that appear before actual matches.

Example:

   true  y
   x     false
   false y

will expand the catch-all x to false.

Catch-alls need also to be expanded if they come before/after a record pattern, otherwise we get into trouble when we want to eliminate splits on records later.

Another example (see Issue 1650): f (x, (y, z)) true = a f _ false = b Split tree: 0 (first argument of f) - 1 (second component of the pair) - 3 (last argument of f) -- true -> a - false -> b We would like to get the following case tree: case 0 of _,_ -> case 1 of _,_ -> case 3 of true -> a; false -> b _ -> case 3 of true -> a; false -> b _ -> case 3 of true -> a; false -> b

substBody :: Int -> Int -> Term -> ClauseBody -> ClauseBody