Alias for variables in pattern matching
I often have something similar to the following (standard type definition for trees):
match tree with
| Branch(v, Branch(vl, tll, tlr), _) = f Branch(vl, tll, tlr)
In other languages there is the ability to do something like:
match tree with
| Branch(v, tl@Branch(_, _, _), _) = f tl
Does OCaml have something similar?
ocaml
add a comment |
I often have something similar to the following (standard type definition for trees):
match tree with
| Branch(v, Branch(vl, tll, tlr), _) = f Branch(vl, tll, tlr)
In other languages there is the ability to do something like:
match tree with
| Branch(v, tl@Branch(_, _, _), _) = f tl
Does OCaml have something similar?
ocaml
add a comment |
I often have something similar to the following (standard type definition for trees):
match tree with
| Branch(v, Branch(vl, tll, tlr), _) = f Branch(vl, tll, tlr)
In other languages there is the ability to do something like:
match tree with
| Branch(v, tl@Branch(_, _, _), _) = f tl
Does OCaml have something similar?
ocaml
I often have something similar to the following (standard type definition for trees):
match tree with
| Branch(v, Branch(vl, tll, tlr), _) = f Branch(vl, tll, tlr)
In other languages there is the ability to do something like:
match tree with
| Branch(v, tl@Branch(_, _, _), _) = f tl
Does OCaml have something similar?
ocaml
ocaml
edited Nov 11 at 18:13
asked Nov 11 at 18:03
Cjen1
8581732
8581732
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
This is done using the as
keyword in OCaml:
match tree with
| Branch(v, (Branch(_, _, _) as tl), _) = f tl
This is failing to compile for me, although it works if I surround theBranch(_,_,_) as tl
in parenthesis
– Cjen1
Nov 11 at 18:23
1
@Cjen1 Right, my mistake. Without the parentheses it takev, Branch(_,_,_)
to be the left operand ofas
.
– sepp2k
Nov 11 at 18:31
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53251626%2falias-for-variables-in-pattern-matching%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
This is done using the as
keyword in OCaml:
match tree with
| Branch(v, (Branch(_, _, _) as tl), _) = f tl
This is failing to compile for me, although it works if I surround theBranch(_,_,_) as tl
in parenthesis
– Cjen1
Nov 11 at 18:23
1
@Cjen1 Right, my mistake. Without the parentheses it takev, Branch(_,_,_)
to be the left operand ofas
.
– sepp2k
Nov 11 at 18:31
add a comment |
This is done using the as
keyword in OCaml:
match tree with
| Branch(v, (Branch(_, _, _) as tl), _) = f tl
This is failing to compile for me, although it works if I surround theBranch(_,_,_) as tl
in parenthesis
– Cjen1
Nov 11 at 18:23
1
@Cjen1 Right, my mistake. Without the parentheses it takev, Branch(_,_,_)
to be the left operand ofas
.
– sepp2k
Nov 11 at 18:31
add a comment |
This is done using the as
keyword in OCaml:
match tree with
| Branch(v, (Branch(_, _, _) as tl), _) = f tl
This is done using the as
keyword in OCaml:
match tree with
| Branch(v, (Branch(_, _, _) as tl), _) = f tl
edited Nov 11 at 18:31
answered Nov 11 at 18:16
sepp2k
292k38593608
292k38593608
This is failing to compile for me, although it works if I surround theBranch(_,_,_) as tl
in parenthesis
– Cjen1
Nov 11 at 18:23
1
@Cjen1 Right, my mistake. Without the parentheses it takev, Branch(_,_,_)
to be the left operand ofas
.
– sepp2k
Nov 11 at 18:31
add a comment |
This is failing to compile for me, although it works if I surround theBranch(_,_,_) as tl
in parenthesis
– Cjen1
Nov 11 at 18:23
1
@Cjen1 Right, my mistake. Without the parentheses it takev, Branch(_,_,_)
to be the left operand ofas
.
– sepp2k
Nov 11 at 18:31
This is failing to compile for me, although it works if I surround the
Branch(_,_,_) as tl
in parenthesis– Cjen1
Nov 11 at 18:23
This is failing to compile for me, although it works if I surround the
Branch(_,_,_) as tl
in parenthesis– Cjen1
Nov 11 at 18:23
1
1
@Cjen1 Right, my mistake. Without the parentheses it take
v, Branch(_,_,_)
to be the left operand of as
.– sepp2k
Nov 11 at 18:31
@Cjen1 Right, my mistake. Without the parentheses it take
v, Branch(_,_,_)
to be the left operand of as
.– sepp2k
Nov 11 at 18:31
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53251626%2falias-for-variables-in-pattern-matching%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown