Lambda interpreter is ready #13
Open
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…/Homework-Semester-4 into LambdaInterpreter
yurii-litvinov
suggested changes
Jun 6, 2020
| let rec isFreeVar expression var = | ||
| match expression with | ||
| | Variable x -> x = var | ||
| | Abstr(vr, term) -> vr = var || (isFreeVar term var) |
There was a problem hiding this comment.
Мм, переменная за лямбдой разве входит свободно? Наоборот, она связанная и должна исключиться из множества свободных в term переменных. Наоборот же, если vr = var, то false
| | Variable x when x = insteadOf -> value | ||
| | Variable -> expression | ||
| | Abstr(var, lmd) when var = insteadOf -> expression | ||
| | Abstr(var, lmd) when not (isFreeVar value var) -> Abstr(var, substitute lmd insteadOf value) |
There was a problem hiding this comment.
А если всё-таки входит свободно? Тоже ведь подстановку надо делать, только после альфа-преобразования
| /// Reduce with left outer term. | ||
| let rec reduceLeftOuter expression = | ||
| match expression with | ||
| | Applic(l, r) -> match reduceLeftOuter l with | Abstr(var, lmd) -> substitute lmd var r | var -> Applic(var, r) |
There was a problem hiding this comment.
Это лучше на разных строчках записать.
Comment on lines
40
to
42
| | Applic(l, r) -> match reduceLeftOuter l with | ||
| | Abstr(var, lmd) -> betaReduction (substitute lmd var r) | ||
| | var -> Applic(betaReduction var, betaReduction r) |
There was a problem hiding this comment.
Это подозрительно похоже на reduceLeftOuter, и неспроста --- это и есть шаг редукции, и тут, и там
yurii-litvinov
approved these changes
Jun 6, 2020
| | Variable -> expression | ||
| | Applic(l, r) -> match reduceLeftOuter l with | ||
| | Abstr(var, lmd) -> betaReduction (substitute lmd var r) | ||
| | var -> Applic(betaReduction var, betaReduction r) |
There was a problem hiding this comment.
Ну, некоторый копипаст между reduceLeftOuter и этим куском кода остался, но ладно
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.