Sophie: ghc-0:6.10.4-1mdv2010.0 i586

ghc-6.10.4-1mdv2010.0.i586.rpm

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<!--Rendered using the Haskell Html Library v0.2-->
<HTML
><HEAD
><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8"
><TITLE
>Coercion</TITLE
><LINK HREF="haddock.css" REL="stylesheet" TYPE="text/css"
><SCRIPT SRC="haddock-util.js" TYPE="text/javascript"
></SCRIPT
><SCRIPT TYPE="text/javascript"
>window.onload = function () {setSynopsis("mini_Coercion.html")};</SCRIPT
></HEAD
><BODY
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="topbar"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD
><IMG SRC="haskell_icon.gif" WIDTH="16" HEIGHT="16" ALT=" "
></TD
><TD CLASS="title"
>ghc-6.10.4: The GHC API</TD
><TD CLASS="topbut"
><A HREF="index.html"
>Contents</A
></TD
><TD CLASS="topbut"
><A HREF="doc-index.html"
>Index</A
></TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="modulebar"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD
><FONT SIZE="6"
>Coercion</FONT
></TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="section4"
><B
>Contents</B
></TD
></TR
><TR
><TD
><DL
><DT
><A HREF="#1"
>Main data type
</A
></DT
><DD
><DL
><DT
><A HREF="#2"
>Equality predicates
</A
></DT
><DT
><A HREF="#3"
>Coercion transformations
</A
></DT
><DT
><A HREF="#4"
>Comparison
</A
></DT
></DL
></DD
><DT
><A HREF="#5"
>CoercionI
</A
></DT
></DL
></TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section1"
>Description</TD
></TR
><TR
><TD CLASS="doc"
><P
>Module for type coercions, as used in System FC. See CoreSyn.Expr for
 more on System FC and how coercions fit into it.
</P
><P
>Coercions are represented as types, and their kinds tell what types the 
 coercion works on. The coercion kind constructor is a special TyCon that must always be saturated, like so:
</P
><PRE
> typeKind (symCoercion type) :: TyConApp CoercionTyCon{...} [type, type]
</PRE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section1"
>Synopsis</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="body"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="decl"
><SPAN CLASS="keyword"
>type</SPAN
> <A HREF="#t%3ACoercion"
>Coercion</A
> = <A HREF="Type.html#t%3AType"
>Type</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkCoKind"
>mkCoKind</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; CoercionKind</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkReflCoKind"
>mkReflCoKind</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; CoercionKind</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AsplitCoercionKind_maybe"
>splitCoercionKind_maybe</A
> :: <A HREF="Type.html#t%3AKind"
>Kind</A
> -&gt; <A HREF="../base/Data-Maybe.html#t%3AMaybe"
>Maybe</A
> (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AsplitCoercionKind"
>splitCoercionKind</A
> :: CoercionKind -&gt; (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AcoercionKind"
>coercionKind</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AcoercionKinds"
>coercionKinds</A
> :: [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>] -&gt; ([<A HREF="Type.html#t%3AType"
>Type</A
>], [<A HREF="Type.html#t%3AType"
>Type</A
>])</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AcoercionKindPredTy"
>coercionKindPredTy</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; CoercionKind</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AisEqPred"
>isEqPred</A
> :: <A HREF="Type.html#t%3APredType"
>PredType</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkEqPred"
>mkEqPred</A
> :: (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>) -&gt; <A HREF="Type.html#t%3APredType"
>PredType</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AgetEqPredTys"
>getEqPredTys</A
> :: <A HREF="Type.html#t%3APredType"
>PredType</A
> -&gt; (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AisEqPredTy"
>isEqPredTy</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkCoercion"
>mkCoercion</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkSymCoercion"
>mkSymCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkTransCoercion"
>mkTransCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkLeftCoercion"
>mkLeftCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkRightCoercion"
>mkRightCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkRightCoercions"
>mkRightCoercions</A
> :: <A HREF="../ghc-prim/GHC-Types.html#t%3AInt"
>Int</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>]</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkInstCoercion"
>mkInstCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkAppCoercion"
>mkAppCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkForAllCoercion"
>mkForAllCoercion</A
> :: <A HREF="Var.html#t%3AVar"
>Var</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkFunCoercion"
>mkFunCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkInstsCoercion"
>mkInstsCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkUnsafeCoercion"
>mkUnsafeCoercion</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkNewTypeCoercion"
>mkNewTypeCoercion</A
> :: <A HREF="Name.html#t%3AName"
>Name</A
> -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Var.html#t%3ATyVar"
>TyVar</A
>] -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkFamInstCoercion"
>mkFamInstCoercion</A
> :: <A HREF="Name.html#t%3AName"
>Name</A
> -&gt; [<A HREF="Var.html#t%3ATyVar"
>TyVar</A
>] -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkAppsCoercion"
>mkAppsCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AsplitNewTypeRepCo_maybe"
>splitNewTypeRepCo_maybe</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="../base/Data-Maybe.html#t%3AMaybe"
>Maybe</A
> (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>)</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AinstNewTyCon_maybe"
>instNewTyCon_maybe</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="../base/Data-Maybe.html#t%3AMaybe"
>Maybe</A
> (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
>)</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AdecomposeCo"
>decomposeCo</A
> :: <A HREF="BasicTypes.html#t%3AArity"
>Arity</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>]</TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AunsafeCoercionTyCon"
>unsafeCoercionTyCon</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AsymCoercionTyCon"
>symCoercionTyCon</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AtransCoercionTyCon"
>transCoercionTyCon</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AleftCoercionTyCon"
>leftCoercionTyCon</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3ArightCoercionTyCon"
>rightCoercionTyCon</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AinstCoercionTyCon"
>instCoercionTyCon</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AcoreEqCoercion"
>coreEqCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="decl"
><SPAN CLASS="keyword"
>data</SPAN
>  <A HREF="#t%3ACoercionI"
>CoercionI</A
>  </TD
></TR
><TR
><TD CLASS="body"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="decl"
>= <A HREF="#v%3AIdCo"
>IdCo</A
></TD
></TR
><TR
><TD CLASS="decl"
>| <A HREF="#v%3AACo"
>ACo</A
> <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
></TABLE
></TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AisIdentityCoercion"
>isIdentityCoercion</A
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkSymCoI"
>mkSymCoI</A
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkTransCoI"
>mkTransCoI</A
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkTyConAppCoI"
>mkTyConAppCoI</A
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; [<A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkAppTyCoI"
>mkAppTyCoI</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkFunTyCoI"
>mkFunTyCoI</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkForAllTyCoI"
>mkForAllTyCoI</A
> :: <A HREF="Var.html#t%3ATyVar"
>TyVar</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AfromCoI"
>fromCoI</A
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AfromACo"
>fromACo</A
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkClassPPredCoI"
>mkClassPPredCoI</A
> :: <A HREF="Class.html#t%3AClass"
>Class</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; [<A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkIParamPredCoI"
>mkIParamPredCoI</A
> :: <A HREF="BasicTypes.html#t%3AIPName"
>IPName</A
> <A HREF="Name.html#t%3AName"
>Name</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="s8"
></TD
></TR
><TR
><TD CLASS="decl"
><A HREF="#v%3AmkEqPredCoI"
>mkEqPredCoI</A
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section1"
><A NAME="1"
><A NAME="1"
>Main data type
</A
></A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><SPAN CLASS="keyword"
>type</SPAN
> <A NAME="t:Coercion"
><A NAME="t%3ACoercion"
></A
></A
><B
>Coercion</B
> = <A HREF="Type.html#t%3AType"
>Type</A
></TD
></TR
><TR
><TD CLASS="doc"
>A <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> represents a <TT
><A HREF="Type.html#t%3AType"
>Type</A
></TT
> something should be coerced to.
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkCoKind"
><A NAME="v%3AmkCoKind"
></A
></A
><B
>mkCoKind</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; CoercionKind</TD
></TR
><TR
><TD CLASS="doc"
>Makes a <TT
>CoercionKind</TT
> from two types: the types whose equality is proven by the relevant <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkReflCoKind"
><A NAME="v%3AmkReflCoKind"
></A
></A
><B
>mkReflCoKind</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; CoercionKind</TD
></TR
><TR
><TD CLASS="doc"
>Create a reflexive <TT
>CoercionKind</TT
> that asserts that a type can be coerced to itself
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:splitCoercionKind_maybe"
><A NAME="v%3AsplitCoercionKind_maybe"
></A
></A
><B
>splitCoercionKind_maybe</B
> :: <A HREF="Type.html#t%3AKind"
>Kind</A
> -&gt; <A HREF="../base/Data-Maybe.html#t%3AMaybe"
>Maybe</A
> (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="doc"
>Take a <TT
>CoercionKind</TT
> apart into the two types it relates, if possible. See also <TT
><A HREF="Coercion.html#v%3AsplitCoercionKind"
>splitCoercionKind</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:splitCoercionKind"
><A NAME="v%3AsplitCoercionKind"
></A
></A
><B
>splitCoercionKind</B
> :: CoercionKind -&gt; (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="doc"
>Take a <TT
>CoercionKind</TT
> apart into the two types it relates: see also <TT
><A HREF="Coercion.html#v%3AmkCoKind"
>mkCoKind</A
></TT
>.
 Panics if the argument is not a valid <TT
>CoercionKind</TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:coercionKind"
><A NAME="v%3AcoercionKind"
></A
></A
><B
>coercionKind</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="doc"
><P
>If it is the case that
</P
><PRE
> c :: (t1 ~ t2)
</PRE
><P
>i.e. the kind of <TT
>c</TT
> is a <TT
>CoercionKind</TT
> relating <TT
>t1</TT
> and <TT
>t2</TT
>, then <TT
>coercionKind c = (t1, t2)</TT
>.
 See also <TT
><A HREF="Coercion.html#v%3AcoercionKindPredTy"
>coercionKindPredTy</A
></TT
>
</P
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:coercionKinds"
><A NAME="v%3AcoercionKinds"
></A
></A
><B
>coercionKinds</B
> :: [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>] -&gt; ([<A HREF="Type.html#t%3AType"
>Type</A
>], [<A HREF="Type.html#t%3AType"
>Type</A
>])</TD
></TR
><TR
><TD CLASS="doc"
>Apply <TT
><A HREF="Coercion.html#v%3AcoercionKind"
>coercionKind</A
></TT
> to multiple <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:coercionKindPredTy"
><A NAME="v%3AcoercionKindPredTy"
></A
></A
><B
>coercionKindPredTy</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; CoercionKind</TD
></TR
><TR
><TD CLASS="doc"
>Recover the <TT
>CoercionKind</TT
> corresponding to a particular Coerceion. See also <TT
><A HREF="Coercion.html#v%3AcoercionKind"
>coercionKind</A
></TT
>
 and <TT
><A HREF="Coercion.html#v%3AmkCoKind"
>mkCoKind</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section2"
><A NAME="2"
><A NAME="2"
>Equality predicates
</A
></A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:isEqPred"
><A NAME="v%3AisEqPred"
></A
></A
><B
>isEqPred</B
> :: <A HREF="Type.html#t%3APredType"
>PredType</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkEqPred"
><A NAME="v%3AmkEqPred"
></A
></A
><B
>mkEqPred</B
> :: (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>) -&gt; <A HREF="Type.html#t%3APredType"
>PredType</A
></TD
></TR
><TR
><TD CLASS="doc"
>Creates a type equality predicate
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:getEqPredTys"
><A NAME="v%3AgetEqPredTys"
></A
></A
><B
>getEqPredTys</B
> :: <A HREF="Type.html#t%3APredType"
>PredType</A
> -&gt; (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Type.html#t%3AType"
>Type</A
>)</TD
></TR
><TR
><TD CLASS="doc"
>Splits apart a type equality predicate, if the supplied <TT
><A HREF="Type.html#t%3APredType"
>PredType</A
></TT
> is one.
 Panics otherwise
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:isEqPredTy"
><A NAME="v%3AisEqPredTy"
></A
></A
><B
>isEqPredTy</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="doc"
>Tests whether a type is just a type equality predicate
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section2"
><A NAME="3"
><A NAME="3"
>Coercion transformations
</A
></A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkCoercion"
><A NAME="v%3AmkCoercion"
></A
></A
><B
>mkCoercion</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Make a coercion from the specified coercion <TT
><A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TT
> and the <TT
><A HREF="Type.html#t%3AType"
>Type</A
></TT
> arguments to
 that coercion. Try to use the <TT
>mk*Coercion</TT
> family of functions instead of using this function
 if possible
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkSymCoercion"
><A NAME="v%3AmkSymCoercion"
></A
></A
><B
>mkSymCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
><P
>Create a symmetric version of the given <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> that asserts equality between
 the same types but in the other <A HREF="direction.html"
>direction</A
>, so a kind of <TT
>t1 ~ t2</TT
> becomes the
 kind <TT
>t2 ~ t1</TT
>.
</P
><P
>This function attempts to simplify the generated <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> by removing redundant applications
 of <TT
>sym</TT
>. This is done by pushing this new <TT
>sym</TT
> down into the <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> and exploiting the fact that 
 <TT
>sym (sym co) = co</TT
>.
</P
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkTransCoercion"
><A NAME="v%3AmkTransCoercion"
></A
></A
><B
>mkTransCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
><P
>Create a new <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> by exploiting transitivity on the two given <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s.
</P
><P
>This function attempts to simplify the generated <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> by exploiting the fact that
 <TT
>sym g trans g = id</TT
>.
</P
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkLeftCoercion"
><A NAME="v%3AmkLeftCoercion"
></A
></A
><B
>mkLeftCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
><P
>From an application <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> build a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> that asserts the equality of 
 the <A HREF="functions.html"
>functions</A
> on either side of the type equality. So if <TT
>c</TT
> has kind <TT
>f x ~ g y</TT
> then:
</P
><PRE
> mkLeftCoercion c :: f ~ g
</PRE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkRightCoercion"
><A NAME="v%3AmkRightCoercion"
></A
></A
><B
>mkRightCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
><P
>From an application <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> build a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> that asserts the equality of 
 the <A HREF="arguments.html"
>arguments</A
> on either side of the type equality. So if <TT
>c</TT
> has kind <TT
>f x ~ g y</TT
> then:
</P
><PRE
> mkLeftCoercion c :: x ~ y
</PRE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkRightCoercions"
><A NAME="v%3AmkRightCoercions"
></A
></A
><B
>mkRightCoercions</B
> :: <A HREF="../ghc-prim/GHC-Types.html#t%3AInt"
>Int</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>]</TD
></TR
><TR
><TD CLASS="doc"
>As <TT
><A HREF="Coercion.html#v%3AmkRightCoercion"
>mkRightCoercion</A
></TT
>, but finds the <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s available on the right side of <TT
>n</TT
>
 nested application <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s, manufacturing new left or right cooercions as necessary
 if suffficiently many are not directly available.
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkInstCoercion"
><A NAME="v%3AmkInstCoercion"
></A
></A
><B
>mkInstCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Instantiates a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> with a <TT
><A HREF="Type.html#t%3AType"
>Type</A
></TT
> argument. If possible, it immediately performs
 the resulting beta-reduction, otherwise it creates a suspended instantiation.
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkAppCoercion"
><A NAME="v%3AmkAppCoercion"
></A
></A
><B
>mkAppCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Apply a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> to another <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>, which is presumably a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> constructor of some
 kind
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkForAllCoercion"
><A NAME="v%3AmkForAllCoercion"
></A
></A
><B
>mkForAllCoercion</B
> :: <A HREF="Var.html#t%3AVar"
>Var</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Make a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> which binds a variable within an inner <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkFunCoercion"
><A NAME="v%3AmkFunCoercion"
></A
></A
><B
>mkFunCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Make a function <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> between two other <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkInstsCoercion"
><A NAME="v%3AmkInstsCoercion"
></A
></A
><B
>mkInstsCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>As <TT
><A HREF="Coercion.html#v%3AmkInstCoercion"
>mkInstCoercion</A
></TT
>, but instantiates the coercion with a number of type arguments, left-to-right
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkUnsafeCoercion"
><A NAME="v%3AmkUnsafeCoercion"
></A
></A
><B
>mkUnsafeCoercion</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Manufacture a coercion from this air. Needless to say, this is not usually safe,
 but it is used when we know we are dealing with bottom, which is one case in which 
 it is safe.  This is also used implement the <TT
>unsafeCoerce#</TT
> primitive.
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkNewTypeCoercion"
><A NAME="v%3AmkNewTypeCoercion"
></A
></A
><B
>mkNewTypeCoercion</B
> :: <A HREF="Name.html#t%3AName"
>Name</A
> -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Var.html#t%3ATyVar"
>TyVar</A
>] -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="doc"
>Create a coercion suitable for the given <TT
><A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TT
>. The <TT
><A HREF="Name.html#t%3AName"
>Name</A
></TT
> should be that of a
 new coercion <TT
><A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TT
>, the <TT
><A HREF="Var.html#t%3ATyVar"
>TyVar</A
></TT
>s the arguments expected by the <TT
>newtype</TT
> and the
 type the appropriate right hand side of the <TT
>newtype</TT
>, with the free variables
 a subset of those <TT
><A HREF="Var.html#t%3ATyVar"
>TyVar</A
></TT
>s.
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkFamInstCoercion"
><A NAME="v%3AmkFamInstCoercion"
></A
></A
><B
>mkFamInstCoercion</B
></TD
></TR
><TR
><TD CLASS="body"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="arg"
>:: <A HREF="Name.html#t%3AName"
>Name</A
></TD
><TD CLASS="rdoc"
>Unique name for the coercion tycon
</TD
></TR
><TR
><TD CLASS="arg"
>-&gt; [<A HREF="Var.html#t%3ATyVar"
>TyVar</A
>]</TD
><TD CLASS="rdoc"
>Type parameters of the coercion (<TT
>tvs</TT
>)
</TD
></TR
><TR
><TD CLASS="arg"
>-&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
><TD CLASS="rdoc"
>Family tycon (<TT
>F</TT
>)
</TD
></TR
><TR
><TD CLASS="arg"
>-&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>]</TD
><TD CLASS="rdoc"
>Type instance (<TT
>ts</TT
>)
</TD
></TR
><TR
><TD CLASS="arg"
>-&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
><TD CLASS="rdoc"
>Representation tycon (<TT
>R</TT
>)
</TD
></TR
><TR
><TD CLASS="arg"
>-&gt; <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
><TD CLASS="rdoc"
>Coercion tycon (<TT
>Co</TT
>)
</TD
></TR
><TR
><TD CLASS="ndoc" COLSPAN="2"
>Create a coercion identifying a <TT
>data</TT
>, <TT
>newtype</TT
> or <TT
>type</TT
> representation type
 and its family instance.  It has the form <TT
>Co tvs :: F ts ~ R tvs</TT
>, where <TT
>Co</TT
> is 
 the coercion tycon built here, <TT
>F</TT
> the family tycon and <TT
>R</TT
> the (derived)
 representation tycon.
</TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkAppsCoercion"
><A NAME="v%3AmkAppsCoercion"
></A
></A
><B
>mkAppsCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Applies multiple <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s to another <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>, from left to right.
 See also <TT
><A HREF="Coercion.html#v%3AmkAppCoercion"
>mkAppCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:splitNewTypeRepCo_maybe"
><A NAME="v%3AsplitNewTypeRepCo_maybe"
></A
></A
><B
>splitNewTypeRepCo_maybe</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="../base/Data-Maybe.html#t%3AMaybe"
>Maybe</A
> (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>)</TD
></TR
><TR
><TD CLASS="doc"
><P
>Sometimes we want to look through a <TT
>newtype</TT
> and get its associated coercion.
 This function only strips *one layer* of <TT
>newtype</TT
> off, so the caller will usually call
 itself recursively. Furthermore, this function should only be applied to types of kind <TT
>*</TT
>,
 hence the newtype is always saturated. If <TT
>co : ty ~ ty'</TT
> then:
</P
><PRE
> splitNewTypeRepCo_maybe ty = Just (ty', co)
</PRE
><P
>The function returns <TT
>Nothing</TT
> for non-<TT
>newtypes</TT
> or fully-transparent <TT
>newtype</TT
>s.
</P
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:instNewTyCon_maybe"
><A NAME="v%3AinstNewTyCon_maybe"
></A
></A
><B
>instNewTyCon_maybe</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; <A HREF="../base/Data-Maybe.html#t%3AMaybe"
>Maybe</A
> (<A HREF="Type.html#t%3AType"
>Type</A
>, <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
>)</TD
></TR
><TR
><TD CLASS="doc"
><P
>If <TT
>co :: T ts ~ rep_ty</TT
> then:
</P
><PRE
> instNewTyCon_maybe T ts = Just (rep_ty, co)
</PRE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:decomposeCo"
><A NAME="v%3AdecomposeCo"
></A
></A
><B
>decomposeCo</B
> :: <A HREF="BasicTypes.html#t%3AArity"
>Arity</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; [<A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
>]</TD
></TR
><TR
><TD CLASS="doc"
><P
>This breaks a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> with <TT
>CoercionKind</TT
> <TT
>T A B C ~ T D E F</TT
> into
 a list of <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s of kinds <TT
>A ~ D</TT
>, <TT
>B ~ E</TT
> and <TT
>E ~ F</TT
>. Hence:
</P
><PRE
> decomposeCo 3 c = [right (left (left c)), right (left c), right c]
</PRE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:unsafeCoercionTyCon"
><A NAME="v%3AunsafeCoercionTyCon"
></A
></A
><B
>unsafeCoercionTyCon</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:symCoercionTyCon"
><A NAME="v%3AsymCoercionTyCon"
></A
></A
><B
>symCoercionTyCon</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:transCoercionTyCon"
><A NAME="v%3AtransCoercionTyCon"
></A
></A
><B
>transCoercionTyCon</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="doc"
>Coercion type constructors: avoid using these directly and instead use the <TT
>mk*Coercion</TT
> and <TT
>split*Coercion</TT
> family
 of functions if possible.
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:leftCoercionTyCon"
><A NAME="v%3AleftCoercionTyCon"
></A
></A
><B
>leftCoercionTyCon</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:rightCoercionTyCon"
><A NAME="v%3ArightCoercionTyCon"
></A
></A
><B
>rightCoercionTyCon</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:instCoercionTyCon"
><A NAME="v%3AinstCoercionTyCon"
></A
></A
><B
>instCoercionTyCon</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section2"
><A NAME="4"
><A NAME="4"
>Comparison
</A
></A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:coreEqCoercion"
><A NAME="v%3AcoreEqCoercion"
></A
></A
><B
>coreEqCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="doc"
>Determines syntactic equality of coercions
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="section1"
><A NAME="5"
><A NAME="5"
>CoercionI
</A
></A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><SPAN CLASS="keyword"
>data</SPAN
>  <A NAME="t:CoercionI"
><A NAME="t%3ACoercionI"
></A
></A
><B
>CoercionI</B
>  </TD
></TR
><TR
><TD CLASS="body"
><TABLE CLASS="vanilla" CELLSPACING="0" CELLPADDING="0"
><TR
><TD CLASS="ndoc"
><P
><TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
> represents a <EM
>lifted</EM
> ordinary <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>, in that it
 can represent either one of:
</P
><P
>1. A proper <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>
</P
><P
>2. The identity coercion
</P
></TD
></TR
><TR
><TD CLASS="section4"
>Constructors</TD
></TR
><TR
><TD CLASS="body"
><TABLE CLASS="vanilla" CELLSPACING="1" CELLPADDING="0"
><TR
><TD CLASS="arg"
><A NAME="v:IdCo"
><A NAME="v%3AIdCo"
></A
></A
><B
>IdCo</B
></TD
><TD CLASS="rdoc"
></TD
></TR
><TR
><TD CLASS="arg"
><A NAME="v:ACo"
><A NAME="v%3AACo"
></A
></A
><B
>ACo</B
> <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
><TD CLASS="rdoc"
></TD
></TR
></TABLE
></TD
></TR
></TABLE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:isIdentityCoercion"
><A NAME="v%3AisIdentityCoercion"
></A
></A
><B
>isIdentityCoercion</B
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="../ghc-prim/GHC-Bool.html#t%3ABool"
>Bool</A
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkSymCoI"
><A NAME="v%3AmkSymCoI"
></A
></A
><B
>mkSymCoI</B
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for <TT
>sym</TT
> on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>, see also <TT
><A HREF="Coercion.html#v%3AmkSymCoercion"
>mkSymCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkTransCoI"
><A NAME="v%3AmkTransCoI"
></A
></A
><B
>mkTransCoI</B
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for <TT
>trans</TT
> on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>, see also <TT
><A HREF="Coercion.html#v%3AmkTransCoercion"
>mkTransCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkTyConAppCoI"
><A NAME="v%3AmkTyConAppCoI"
></A
></A
><B
>mkTyConAppCoI</B
> :: <A HREF="TyCon.html#t%3ATyCon"
>TyCon</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; [<A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for type constructor application on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>, see also <TT
><A HREF="Coercion.html#v%3AmkAppCoercion"
>mkAppCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkAppTyCoI"
><A NAME="v%3AmkAppTyCoI"
></A
></A
><B
>mkAppTyCoI</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for honest-to-god <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> application on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>, see also <TT
><A HREF="Coercion.html#v%3AmkAppCoercion"
>mkAppCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkFunTyCoI"
><A NAME="v%3AmkFunTyCoI"
></A
></A
><B
>mkFunTyCoI</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for function-<TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>, see also <TT
><A HREF="Coercion.html#v%3AmkFunCoercion"
>mkFunCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkForAllTyCoI"
><A NAME="v%3AmkForAllTyCoI"
></A
></A
><B
>mkForAllTyCoI</B
> :: <A HREF="Var.html#t%3ATyVar"
>TyVar</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for quantified <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>, see also <TT
><A HREF="Coercion.html#v%3AmkForAllCoercion"
>mkForAllCoercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:fromCoI"
><A NAME="v%3AfromCoI"
></A
></A
><B
>fromCoI</B
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
></TD
></TR
><TR
><TD CLASS="doc"
>Return either the <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> contained within the <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
> or the given
 <TT
><A HREF="Type.html#t%3AType"
>Type</A
></TT
> if the <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
> is the identity <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:fromACo"
><A NAME="v%3AfromACo"
></A
></A
><B
>fromACo</B
> :: <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TD
></TR
><TR
><TD CLASS="doc"
>Extract a <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
> from a <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
> if it represents one. If it is the identity coercion,
 panic
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkClassPPredCoI"
><A NAME="v%3AmkClassPPredCoI"
></A
></A
><B
>mkClassPPredCoI</B
> :: <A HREF="Class.html#t%3AClass"
>Class</A
> -&gt; [<A HREF="Type.html#t%3AType"
>Type</A
>] -&gt; [<A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
>] -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
><P
>Smart constructor for class <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>. Satisfies:
</P
><PRE
> mkClassPPredCoI cls tys cois :: PredTy (cls tys) ~ PredTy (cls (tys `cast` cois))
</PRE
></TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkIParamPredCoI"
><A NAME="v%3AmkIParamPredCoI"
></A
></A
><B
>mkIParamPredCoI</B
> :: <A HREF="BasicTypes.html#t%3AIPName"
>IPName</A
> <A HREF="Name.html#t%3AName"
>Name</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for implicit parameter <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>. Similar to <TT
><A HREF="Coercion.html#v%3AmkClassPPredCoI"
>mkClassPPredCoI</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="decl"
><A NAME="v:mkEqPredCoI"
><A NAME="v%3AmkEqPredCoI"
></A
></A
><B
>mkEqPredCoI</B
> :: <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Type.html#t%3AType"
>Type</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
> -&gt; <A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TD
></TR
><TR
><TD CLASS="doc"
>Smart constructor for type equality <TT
><A HREF="Coercion.html#t%3ACoercion"
>Coercion</A
></TT
>s on <TT
><A HREF="Coercion.html#t%3ACoercionI"
>CoercionI</A
></TT
>. Similar to <TT
><A HREF="Coercion.html#v%3AmkClassPPredCoI"
>mkClassPPredCoI</A
></TT
>
</TD
></TR
><TR
><TD CLASS="s15"
></TD
></TR
><TR
><TD CLASS="botbar"
>Produced by <A HREF="http://www.haskell.org/haddock/"
>Haddock</A
> version 2.4.2</TD
></TR
></TABLE
></BODY
></HTML
>