Skip to content

Commit

Permalink
added test cases for partial evaluation
Browse files Browse the repository at this point in the history
  • Loading branch information
@nwokafor-choongsaeng
nwokafor-choongsaeng committed Jul 9, 2023
1 parent 1d7f772 commit 6f06a8e
Show file tree
Hide file tree
Showing 2 changed files with 125 additions and 1,060 deletions.
72 changes: 40 additions & 32 deletions src/Morphir/Value/Interpreter.elm
View file
Original file line number Diff line number Diff line change
Expand Up @@ -380,53 +380,58 @@ evaluateValue ({ allowPartial } as config) nativeFunctions ir variables argument

(Value.IfThenElse _ condition thenBranch elseBranch) as ifThenElse ->
if allowPartial then
-- When allow partial is true, we need to first evaluate all the conditions.
-- We need to go through the evaluated conditions, looking for either a condition that evaluated to True
-- When allow partial is true, we first evaluate all the conditions.
-- We need to go through the evaluated conditions, looking for either a True
-- or a partially evaluated condition. If we find a True before a partially evaluated condition, we take
-- that branch. If we find a condition that was only partially evaluated first, then we evaluate
-- all branches and preserve the IfThenElse value with the evaluated branches and conditions.
-- that branch. If we find a condition that was only partially evaluated first, then we evaluate that and
-- all other branches and preserve the IfThenElse structure with the evaluated branches and conditions.
-- If neither was found, we take the else branch.
let
flatten : RawValue -> List ( RawValue, RawValue ) -> List ( RawValue, RawValue )
flatten : RawValue -> List ( RawValue, RawValue ) -> ( List ( RawValue, RawValue ), RawValue )
flatten v branchesSoFar =
case v of
Value.IfThenElse _ cond then_ else_ ->
( cond, then_ )
:: branchesSoFar
|> flatten else_

_ ->
branchesSoFar
finalElse ->
( branchesSoFar, finalElse )

( flattened, finalElseBranch ) =
flatten ifThenElse []

chooseBranch : List ( RawValue, RawValue ) -> Result Error RawValue
chooseBranch condByBranches =
case condByBranches of
chooseBranch conditionByBranches =
case conditionByBranches of
[] ->
-- If we got this far, then we never encountered an partially evaluated condition
-- or a True, evaluate the else branch
evaluateValue config nativeFunctions ir variables [] elseBranch
-- We never encountered a partially evaluated condition or a True
-- evaluate the else branch
evaluateValue config nativeFunctions ir variables [] finalElseBranch

( Value.Literal _ (BoolLiteral True), branch ) :: _ ->
-- We met a True first, evaluate this branch
evaluateValue config nativeFunctions ir variables [] branch

( Value.Literal _ (BoolLiteral False), _ ) :: rest ->
-- If the branch is False, continue looking for True or a partially evaluated condition
-- Unreachable branch, skip entirely and continue looking
-- for True or a partially evaluated condition
chooseBranch rest

_ ->
-- We encountered a partially evaluated condition,
-- evaluate all branches and wrap with an IfThenElse
condByBranches
-- TODO we could remove all the unreachable branches
conditionByBranches
|> -- starting from the tail, chain the values into an IfThenElse
List.foldr
(\( cond, branch ) ->
Result.map2 (Value.IfThenElse () cond)
(evaluateValue config nativeFunctions ir variables [] branch)
)
(evaluateValue config nativeFunctions ir variables [] elseBranch)
(evaluateValue config nativeFunctions ir variables [] finalElseBranch)
in
flatten ifThenElse []
flattened
|> List.reverse
|> List.map
(\( cond, branch ) ->
Expand All @@ -439,7 +444,7 @@ evaluateValue ({ allowPartial } as config) nativeFunctions ir variables argument
|> Result.andThen chooseBranch

else
-- When allow partial is false, If then else evaluation becomes trivial: you evaluate the condition
-- When allow partial is false, If-then-else evaluation becomes trivial: you evaluate the condition
-- and depending on the result you evaluate one of the branches
evaluateValue config nativeFunctions ir variables [] condition
|> Result.andThen
Expand Down Expand Up @@ -515,25 +520,28 @@ evaluateValue ({ allowPartial } as config) nativeFunctions ir variables argument
findMatch restOfCases evaluatedSubject

[] ->
if allowPartial then
cases
|> List.foldl
(\( patt, body ) evaluatedBranchesSoFar ->
Result.map2 (\evaluatedBody lst -> ( patt, evaluatedBody ) :: lst)
-- evaluate each body with any new variables from it's pattern added to the state
(evaluateValue config nativeFunctions ir (collectNewVars patt) [] body)
evaluatedBranchesSoFar
)
(Ok [])
|> Result.map (Value.PatternMatch () evaluatedSubject)

else
Err (NoPatternsMatch evaluatedSubject (cases |> List.map Tuple.first))
Err (NoPatternsMatch evaluatedSubject (cases |> List.map Tuple.first))
in
evaluatedSubjectResult
-- if the subject value was not evaluated further and we allow partial evaluation,
-- then we exit with the entire evaluation with the
|> Result.andThen (findMatch cases)
|> Result.andThen
(\evalSubject ->
if allowPartial then
cases
|> List.foldr
(\( patt, body ) evaluatedBranchesSoFar ->
Result.map2 (\evaluatedBody lst -> ( patt, evaluatedBody ) :: lst)
-- evaluate each body with any new variables from it's pattern added to the state
(evaluateValue config nativeFunctions ir (collectNewVars patt) [] body)
evaluatedBranchesSoFar
)
(Ok [])
|> Result.map (Value.PatternMatch () evalSubject)

else
findMatch cases evalSubject
)

Value.UpdateRecord _ subjectValue fieldUpdates ->
-- To update a record first we need to evaluate the subject value, then extract the record fields and
Expand Down
Loading

0 comments on commit 6f06a8e

Please sign in to comment.