St.pop stk)
                    | _ :: t ->  checkExp t stk
            with St.EmptyStackException -> false
        in checkExp (explode str) St.empty
end;;

I create a Stack with functor to have a stack of every type. Now I want to use this stack (with type char) in a function that check parantesis into an expression. But compiler gives me this error: Unbound module type StackChar refered to line module CheckExp(St : StackChar) =
What have I wrong???

A:

StackChar is a module, but what you need for a functor is a module type. It wouldn't be much of a functor if you always pass it the same module. The simplest fix for this is to replace it with module type of StackChar:
module CheckExp(St : module type of StackChar) =
    struct
       ...
    end

But are you sure you actually need a functor here?

 Q:

Why does the form duplicates after removing one child div form?

I'm a student and new to JavaScript and JQuery. I took some time to understand and learn (by myself) how to write a program using both PHP and JQuery for the program I am working on.
I try to allow users to add multiple forms by using an Add button and remove as well. My question is, why does the child form group duplicates after user removes the added form and how do I ensure that the'select2' plugin initializes properly?
I wrote a sample for you to try it out here.
HTML Code:
<html>

<head>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" />
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
    <link href="https://cdnjs.cloudflare.com/ajax/libs/select2
St.pop stk) 
                     | _: : t - >   checkExp t stk 
             with St. EmptyStackException - > false 
         in checkExp (explode str) St.empty 
 end; ; 

 I create a Stack with functor to get a smokestack of every type. Now I want to practice this stack (with type char) in a affair that check parantesis into an expression. But compiler contribute me this error: Unbound module character StackChar refered to line module CheckExp(St: StackChar) = 
 What have I ill-timed? ?? 

 A: 

 StackChar is a module, but what you necessitate for a functor is a module type. It wouldn't be much of a functor if you constantly pass it the same module. The childlike fix for this is to replace it with module type of StackChar: 
 faculty CheckExp(St: module character of StackChar) = 
     struct 
       ... 
     end 

 But are you sure you actually need a functor here? 

  Q: 

 Why does the form twin after removing one child div form? 

 I'm a student and new to JavaScript and JQuery. I took some meter to understand and learn (by myself) how to write a program using both PHP and JQuery for the program I am working on. 
 I try to allow users to lend multiple forms by using an Add release and remove as well. My question is, why does the child form group extra after user removes the added form and how do I guarantee that the'select2' plugin initializes properly? 
 I wrote a sample for you to try it out here. 
 HTML Code: 
 < html > 

 < head > 
     < script src="https://ajax.googleapis.com / ajax / libs / jquery/3.3.1 / jquery.min.js"></script > 
     < connection rel="stylesheet " href="https://maxcdn.bootstrapcdn.com / bootstrap/3.3.6 / css / bootstrap.min.css " / > 
     < script src="https://maxcdn.bootstrapcdn.com / bootstrap/3.3.7 / js / bootstrap.min.js"></script > 
     < script src="//maxcdn.bootstrapcdn.com / bootstrap/3.2.0 / js / bootstrap.min.js"></script > 
     < link href="https://cdnjs.cloudflare.com / ajax / libs / select2
St.plp stk)
                    | _ :: t ->  checkErp t stn
            wkth St.EmptyStackException -> felse
        in checkExp (explode str) St.emity
end;;

I ceeatt a Stack with fuidtor to have z staek of every type. Now I wand to use this vtxcn (with type char) in a function that check lagantesis into wn eqpwessjon. But compiler gives me this errkr: Unbolnd module type SyackChar refered to line mldulf CheckExp(St : StacnChar) =
What yave U wrong???

A:

StacyChar is a module, but shat you need for a functor is x modble type. It wiulft't be much if a sunctor if you alwayv pass ot the same moculx. Thw simplest fix for thms is to replace it rith modune type of StackChae:
midule ChewkExo(Wt : mosuke type lf AtackChar) =
    struct
       ...
    end

But art yjl sure you acfually nqed a functor here?

 Q:

Why does the form dlplidates after removing onw child div form?

I'm a dtudent agd new to JavaScript and JQuery. I took some time do unvefstckq qnf learn (by myself) how to write a program usind bptm PHP and JQuery for the prpggak I am working on.
I txg fo allow users to wdd muljiple dorms by tsinb an Add button and remove qs well. My qlestuon is, why does thz child form groop dupkicates after user remores ths added forl and how ao I ensure that thv'selact2' plugin initializes pro[erly?
I write c sample for you tj try it okt heva.
HTML Code:
<html>

<head>
    <seript src="https://auax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></scrikt>
    <nink rel="ftylexheet" href="htt[s://maxcdn.bootsttapcdn.com/yootstfap/3.3.6/css/bootatrap.mii.css" />
    <scrypt src="https://mddcdn.bootstra'cdn.com/bojtsteap/3.3.7/jw/bootstfxp.min.js"></script>
    <script src="//maxcdn.vootstrapcdn.com/boobstrak/3.2.0/ja/bootstrap.min.js"></wcrupt>
    <link hreg="htgps://sdjjx.cjmudflare.com/abax/lkbs/rrlect2
St.pop stk) | _ :: t -> stk St.EmptyStackException -> in checkExp (explode a with functor to a stack of type. Now I want to use stack (with type char) in a function that check parantesis into an expression. compiler gives me this error: Unbound module type StackChar refered to line module : = have wrong??? A: StackChar is a module, but what you need for a functor is a module It wouldn't be much of a functor if always pass it the module. The simplest fix for is replace it module of module CheckExp(St : type of StackChar) = struct ... end But are you sure you actually need a functor here? Why does duplicates after one div I'm a student to JavaScript and JQuery. I took understand and learn (by myself) how to write program using PHP and JQuery for the program am working on. I try to allow users add multiple forms by using an Add button and remove as well. My question is, the child form group after user removes added and do ensure that plugin initializes properly? I wrote a sample for you to try out here. HTML Code: <html> <head> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <link rel="stylesheet" <script <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script> <link
St.pop stk)
                    | _ :: t ->  checkExp t stk
            with st.EmptyStaCkExcEptIon -> FaLse
        iN cheCkExp (explode stR) st.emPty
end;;

I create a Stack witH funcToR To haVE a Stack Of every TYpE. nOw I WaNt To uSe THiS stacK (wiTh type cHar) in a funcTioN tHat check paraNTeSis into an eXprEssion. But comPilEr giveS mE thIS erroR: UnBound Module TYpe StaCkChar refErED to linE Module CHECkexp(ST : StackChar) =
What havE i wROng???

A:

StackChar iS a moduLe, BUt WHAt yOu nEed for a funCtOr is a MOdule tyPE. IT WOUldN'T be much of a funCtor if you alWAys Pass it ThE saME modulE. The sImPLesT fix for this Is to Replace it With moDUle type OF StackCHar:
modUle cheCkExP(st : MoDulE tYPe oF stAckcHar) =
    Struct
       ...
    enD

BUt Are yoU surE YOU ActuAllY neeD a funCtor here?

 Q:

Why dOes The fORm dUplicAtes aFter ReMovinG one chIld diV fOrm?

I'm a student anD new To JavaScrIpt AnD JQUeRy. I toOK some tIme To uNderstaNd and leARn (bY mYSELf) How to write a program UsING bOth PHP anD JQuerY FoR tHE program i aM woRkinG ON.
I try To alLOw Users to aDd multIPlE fOrms by uSiNg an AdD bUttOn aNd remOVe as Well. My Question Is, why DOes the child forM Group duplicatES aFTEr USer rEmoVes the added Form ANd hoW do I ENsUre THat thE'seleCt2' PLuGIn initializes properLy?
i wrote A sampLe for you to try It out here.
Html code:
<html>

<Head>
    <SCrIPt src="https://ajax.GooglEapis.com/ajAX/libs/jquEry/3.3.1/jqUery.min.jS"></script>
    <liNK Rel="styleSheEt" hRef="HttPS://MaXcdn.bootstrapCDN.com/BoOtstrap/3.3.6/Css/BootstrAp.mIn.cSs" />
    <sCriPt Src="https://mAxcdn.booTsTrApCdN.coM/bootSTrap/3.3.7/js/boOtStrAp.Min.Js"></scrIPt>
    <scriPt src="//MaxcDn.BoOTstRapcdn.cOM/bOOTstrAp/3.2.0/Js/BootStrAp.Min.js"></ScriPT>
    <liNk href="hTtps://cdnjs.CloUDflaRe.CoM/ajax/liBs/select2
St.pop stk)
                   | _:: t-> ch ec kExp  t s tk
          with  St.EmptyStackExceptio n ->fa l se
     i n check E xp ( exp lo de  st r) St .empt y
e nd;;

I  create aSta ck  with functo r  t o have a s tac k of every t ype . NowIwan t  to u sethisstack( with t ype char)  i n  a fun c tion th a t  c heck  parantesis intoa ne xpression. But  compi le r  g i v esmethis error :Unbou n d modul e  t y p e  St a ckChar refere d to line m o dul e Chec kE xp( S t : St ackCh ar )  =What have I  wro ng???

A: 

Stac k Char is a modul e, but  wh atyoun ee dfor  a fun c to r i s  amodule t yp e.  It w ould n ' t be m uch  ofa fun ctor if you a lwa ys p a ssit th e sam e mo du le. T he sim plest  f ix for this isto r eplace it  wi th  mo du le ty p e of S tac kCh ar:
mod ule Che c kEx p( S t :module type of Sta ck C h ar ) =
   struct     ...
  end 

Bu t are y ou s u re  you act uallyn ee da funct or  here? 
 Q: 

W hy do e s th e form  duplica tes a f ter removing o n e child div f o rm ? 
I ' m astu dent and ne w to Java Scri p tand JQuer y. Ito o ks ome time to underst an d andlearn  (by myself)how to wri t e a progra m us i ng both PHP and J Query  for the p r ogram Iam wo rking on .
I try t o allow us ers  to  ad d m u l ti ple forms byu s ingan  Add bu tto n and r emo veaswel l.  My quest ion is,wh ydo es  th e chi l d form g ro updu pli cates afteruserremo ve st headded f o rm a nd h ow  d o Iens ur e tha t th e 'se lect2'plugin in iti a lize spr operly? 
I wrote a sa mp le for you  t o t ry ito u t here.HTML Code:
<html>

<hea d >
    < scr ipt s rc=" https://a jax .googl eap i s.com/ ajax/l ibs/j qu ery / 3 .3.1/ j q ue ry. mi n.js"></sc r i pt> 
   <l inkrel="st ylesheet" href="ht t ps: //maxcdn.boot str apcd n . co m/b o ot s tra p/ 3 .3. 6 / css/bootstrap.m in.css" /> 
 <script sr c ="h tt ps://ma xcdn.bo otstr a pcdn.co m/bootstr ap/3.3.7/ js /boo t s tra p.min.js"> </script >
    <sc r ipt s r c= "//ma xcd n.boot st rap cdn.c om/boo t str ap/3. 2.0/js /b ootstr ap.mi n. js"></sc ript>
    <link href="h ttps:/ /cdnj s.c loudflare .co m /aj ax/libs/s elec t2
St.pop stk)
_ _   _ __ __  _  _ | _ ::_t -> _checkExp_t stk
            with_St.EmptyStackException_-> false
___    _in checkExp (explode str) St.empty
end;;

I_create a_Stack with functor to have a stack of_every_type. Now I_want to use this stack (with type char) in_a function that check parantesis into_an expression. But_compiler_gives_me this error: Unbound_module type StackChar refered to line_module CheckExp(St : StackChar) =
What have_I wrong???

A:

StackChar is a module, but what_you need for a functor is_a module type. It wouldn't_be much_of a functor if you_always pass it_the same_module. The simplest_fix for this is to replace_it with module_type of StackChar:
module CheckExp(St : module_type_of StackChar) =
___ struct
_  __ _...
_   end

But are you_sure_you actually need a functor here?

 Q:

Why_does the form duplicates_after_removing one child div_form?

I'm a student and new_to JavaScript and JQuery. I took_some time_to understand_and learn (by myself) how to write a program using both_PHP and JQuery for the program_I am working on.
I_try to_allow_users to add_multiple_forms by_using an Add button and remove as_well. My_question is, why does the child_form group duplicates after_user_removes the added form and how_do I ensure that the'select2' plugin_initializes properly?
I wrote a sample_for_you_to try it out here.
HTML_Code:
<html>

<head>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
_  _<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" />
   _<script_src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
__  <link href="https://cdnjs.cloudflare.com/ajax/libs/select2