Create new bounded number data types in Haskell











up vote
0
down vote

favorite












I need to create a data type, that represents only the real numbers between 0 and 1. How would i go about that? Expected Behavior:



0 :: DataType        ===> DataType 0

(-1) :: DataType     ===> Error





haskell types numbers







share|improve this question




















  • 6




    You could write an instance Num DataType and define fromInteger so that it errors out on invalid values. I'm not sure if that's a good idea, but it's the only way to achieve your goal.
    – chi
    Nov 22 at 14:38










  • @chi I actually suspect a transcription error there, given that it's ascribing function types to literals. Not impossible, but I suspect that it's actually about creating a function to behave in such a way.
    – Carl
    Nov 22 at 14:50










  • @Carl I'm pretty sure the above -> represents "evaluates to", not function arrow. My comment assumed that interpretation, otherwise the question makes no sense. I'm now replacing them with ==> to avoid confusion.
    – chi
    Nov 22 at 15:12








  • 1




    Beyond instance Num DataType, for real numbers we would also need instance Fractional DataType, and define a partial fromRational to reject invalid numbers.
    – chi
    Nov 22 at 15:16






  • 1




    Have you considered using smart constructors. Might by a good idea here. wiki.haskell.org/Smart_constructors
    – Luis Morillo
    Nov 23 at 8:49

















up vote
0
down vote

favorite












I need to create a data type, that represents only the real numbers between 0 and 1. How would i go about that? Expected Behavior:



0 :: DataType        ===> DataType 0

(-1) :: DataType     ===> Error





haskell types numbers







share|improve this question




















  • 6




    You could write an instance Num DataType and define fromInteger so that it errors out on invalid values. I'm not sure if that's a good idea, but it's the only way to achieve your goal.
    – chi
    Nov 22 at 14:38










  • @chi I actually suspect a transcription error there, given that it's ascribing function types to literals. Not impossible, but I suspect that it's actually about creating a function to behave in such a way.
    – Carl
    Nov 22 at 14:50










  • @Carl I'm pretty sure the above -> represents "evaluates to", not function arrow. My comment assumed that interpretation, otherwise the question makes no sense. I'm now replacing them with ==> to avoid confusion.
    – chi
    Nov 22 at 15:12








  • 1




    Beyond instance Num DataType, for real numbers we would also need instance Fractional DataType, and define a partial fromRational to reject invalid numbers.
    – chi
    Nov 22 at 15:16






  • 1




    Have you considered using smart constructors. Might by a good idea here. wiki.haskell.org/Smart_constructors
    – Luis Morillo
    Nov 23 at 8:49















up vote
0
down vote

favorite









up vote
0
down vote

favorite











I need to create a data type, that represents only the real numbers between 0 and 1. How would i go about that? Expected Behavior:



0 :: DataType        ===> DataType 0

(-1) :: DataType     ===> Error





haskell types numbers







share|improve this question















I need to create a data type, that represents only the real numbers between 0 and 1. How would i go about that? Expected Behavior:



0 :: DataType        ===> DataType 0

(-1) :: DataType     ===> Error





haskell types numbers




haskell types numbers






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 22 at 15:13









chi

72.6k280135




72.6k280135










asked Nov 22 at 14:27









Agilix

10111




10111








  • 6




    You could write an instance Num DataType and define fromInteger so that it errors out on invalid values. I'm not sure if that's a good idea, but it's the only way to achieve your goal.
    – chi
    Nov 22 at 14:38










  • @chi I actually suspect a transcription error there, given that it's ascribing function types to literals. Not impossible, but I suspect that it's actually about creating a function to behave in such a way.
    – Carl
    Nov 22 at 14:50










  • @Carl I'm pretty sure the above -> represents "evaluates to", not function arrow. My comment assumed that interpretation, otherwise the question makes no sense. I'm now replacing them with ==> to avoid confusion.
    – chi
    Nov 22 at 15:12








  • 1




    Beyond instance Num DataType, for real numbers we would also need instance Fractional DataType, and define a partial fromRational to reject invalid numbers.
    – chi
    Nov 22 at 15:16






  • 1




    Have you considered using smart constructors. Might by a good idea here. wiki.haskell.org/Smart_constructors
    – Luis Morillo
    Nov 23 at 8:49
















  • 6




    You could write an instance Num DataType and define fromInteger so that it errors out on invalid values. I'm not sure if that's a good idea, but it's the only way to achieve your goal.
    – chi
    Nov 22 at 14:38










  • @chi I actually suspect a transcription error there, given that it's ascribing function types to literals. Not impossible, but I suspect that it's actually about creating a function to behave in such a way.
    – Carl
    Nov 22 at 14:50










  • @Carl I'm pretty sure the above -> represents "evaluates to", not function arrow. My comment assumed that interpretation, otherwise the question makes no sense. I'm now replacing them with ==> to avoid confusion.
    – chi
    Nov 22 at 15:12








  • 1




    Beyond instance Num DataType, for real numbers we would also need instance Fractional DataType, and define a partial fromRational to reject invalid numbers.
    – chi
    Nov 22 at 15:16






  • 1




    Have you considered using smart constructors. Might by a good idea here. wiki.haskell.org/Smart_constructors
    – Luis Morillo
    Nov 23 at 8:49










6




6




You could write an instance Num DataType and define fromInteger so that it errors out on invalid values. I'm not sure if that's a good idea, but it's the only way to achieve your goal.
– chi
Nov 22 at 14:38




You could write an instance Num DataType and define fromInteger so that it errors out on invalid values. I'm not sure if that's a good idea, but it's the only way to achieve your goal.
– chi
Nov 22 at 14:38












@chi I actually suspect a transcription error there, given that it's ascribing function types to literals. Not impossible, but I suspect that it's actually about creating a function to behave in such a way.
– Carl
Nov 22 at 14:50




@chi I actually suspect a transcription error there, given that it's ascribing function types to literals. Not impossible, but I suspect that it's actually about creating a function to behave in such a way.
– Carl
Nov 22 at 14:50












@Carl I'm pretty sure the above -> represents "evaluates to", not function arrow. My comment assumed that interpretation, otherwise the question makes no sense. I'm now replacing them with ==> to avoid confusion.
– chi
Nov 22 at 15:12






@Carl I'm pretty sure the above -> represents "evaluates to", not function arrow. My comment assumed that interpretation, otherwise the question makes no sense. I'm now replacing them with ==> to avoid confusion.
– chi
Nov 22 at 15:12






1




1




Beyond instance Num DataType, for real numbers we would also need instance Fractional DataType, and define a partial fromRational to reject invalid numbers.
– chi
Nov 22 at 15:16




Beyond instance Num DataType, for real numbers we would also need instance Fractional DataType, and define a partial fromRational to reject invalid numbers.
– chi
Nov 22 at 15:16




1




1




Have you considered using smart constructors. Might by a good idea here. wiki.haskell.org/Smart_constructors
– Luis Morillo
Nov 23 at 8:49






Have you considered using smart constructors. Might by a good idea here. wiki.haskell.org/Smart_constructors
– Luis Morillo
Nov 23 at 8:49



















active

oldest

votes











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',
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
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53433088%2fcreate-new-bounded-number-data-types-in-haskell%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown






























active

oldest

votes













active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































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.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53433088%2fcreate-new-bounded-number-data-types-in-haskell%23new-answer', 'question_page');
}
);

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







-

Popular posts from this blog

Contact image not getting when fetch all contact list from iPhone by CNContact

Image
up vote 0 down vote favorite I know this question already asked but not getting solution. From this code I will get all the information from the contact but image not found when open vcf files on mac os, also not getting when share this file. I use this stackoverflow link here but It's not help full. var contacts = [CNContact]() let keys = [CNContactVCardSerialization.descriptorForRequiredKeys() ] as [Any] let request = CNContactFetchRequest(keysToFetch: keys as! [CNKeyDescriptor]) do { try self.contactStore.enumerateContacts(with: request) { (contact, stop) in // Array containing all unified contacts from everywhere contacts.append(contact) } } catch { print("unable to fetch contacts") } do { let data = try
Read more

count number of partitions of a set with n elements into k subsets

Image
up vote 6 down vote favorite 1 This program is for count number of partitions of a set with n elements into k subsets I am confusing here return k*countP(n-1, k) + countP(n-1, k-1); can some one explain what is happening here? why we are multiplying with k? NOTE->I know this is not the best way to calculate number of partitions that would be DP // A C++ program to count number of partitions // of a set with n elements into k subsets #include<iostream> using namespace std; // Returns count of different partitions of n // elements in k subsets int countP(int n, int k) { // Base cases if (n == 0 || k == 0 || k > n) return 0; if (k == 1 || k == n) return 1; // S(n+1, k) = k*S(n, k) + S(n, k-1) return k*countP(n-1, k) + countP(n-1, k-1); } // Driver program int ma
Read more

A CLEAN and SIMPLE way to add appendices to Table of Contents and bookmarks

Image
0 I found a lot of questions abount appendices and ToC. Many users want appendices to be grouped in an Appendix part, however some problems arise with ToC, hyperref, PDF viewer bookmarks, and so on. There are different solutions which require extra packages, command patching and other extra code, however none of them satisfies me. I almost found an easy way to accomplish a good result, where appendices are added to bookmarks in the right way and hyperref links point to the right page. However, the number of the "Appendix" part page is wrong (it's the number of appendix A). Is there any EASY way to fix that? This is a MWE: documentclass{book} usepackage[nottoc,notlot,notlof]{tocbibind} usepackage{hyperref} begin{document} frontmatter tableofcontents mainmatter part{First} chapter{
Read more