Modify identity of NaNs so they are identical iff they are bit identical.

docs/language/dartLangSpec.tex

 \documentclass{article}
 \usepackage{epsfig}
 \usepackage{dart}
 \usepackage{bnf}
 \usepackage{hyperref}
 \newcommand{\code}[1]{{\sf #1}}
 \title{Dart Programming Language  Specification \\
 {\large Version 1.4}}
 %\author{The Dart Team}
 \begin{document}
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 The predefined Dart function \cd{identical()} is defined such that \code{identical($c_1$, $c_2$)} iff:
  \begin{itemize}
  \item $c_1$  evaluates to either \NULL{} or  an instance of \code{bool} and \code{$c_1$ == $c_2$}, OR
  \item $c_1$ and $c_2$ are instances of \code{int} and \code{$c_1$ == $c_2$}, OR
  \item $c_1$ and $c_2$ are constant strings and \code{$c_1$ == $c_2$}, OR
  \item $c_1$  and $c_2$  are instances of \cd{double} and  one of the following holds:
  \begin{itemize}
    \item $c_1$ and $c_2$ are non-zero and \code{$c_1$ == $c_2$}.
    \item  Both $c_1$ and $c_2$ are $+0.0$.
    \item Both  $c_1$ and $c_2$ are $-0.0$.
-   \item Both $c_1$ and $c_2$ represent a NaN value.
+   \item Both $c_1$ and $c_2$ represent a NaN value with the same underlying bit pattern.
  \end{itemize}
  OR
  \item $c_1$ and $c_2$ are constant lists that are defined to be identical in the specification of literal list expressions (\ref{lists}), OR
  \item $c_1$ and $c_2$ are constant maps that are defined to be identical in the specification of literal map expressions (\ref{maps}), OR
  \item $c_1$ and $c_2$ are constant objects of the same class $C$ and each member field of $c_1$ is identical to the corresponding field of $c_2$. OR
 \item $c_1$ and $c_2$ are the same object.
 \end{itemize}
     
 \commentary{
 The definition of \cd{identity} for doubles differs from that of equality in that a NaN is equal to itself, and that negative and positive zero are distinct.  
@@ skipping 507 matching lines @@
     .
 \end{grammar}
 
 A {\em map literal} consists of zero or more entries. Each entry has a {\em key} and a {\em value}.  Each key and each value is denoted by an expression. 
  
 If a map literal begins with the reserved word \CONST{}, it is a {\em constant map literal} which is a compile-time constant (\ref{constants}) and therefore evaluated at compile-time. Otherwise, it is a {\em run-time map literal} and it is evaluated at run-time. Only run-time map literals can be mutated
 after they are created. Attempting to mutate a constant map literal will result in a dynamic error.
 
 It is a compile-time error if either a key or a value of an entry in a constant map literal is not a compile-time constant. It is a compile-time error if the key of an entry in a constant map literal is an instance of a class that implements the operator $==$ unless the key is a 
 %symbol, 
-string, an integer, literal symbol or the result of invoking a constant constructor of class \cd{Symbol}. It is a compile-time error if the type arguments of a constant map literal include a type parameter. 
+string, an integer, a literal symbol or the result of invoking a constant constructor of class \cd{Symbol}. 
+It is a compile-time error if the type arguments of a constant map literal include a type parameter. 
 
 The value of a constant map literal  \CONST{}$ <K, V>\{k_1:e_1\ldots k_n :e_n\}$ is an object $m$ whose class implements the built-in class $Map<K, V>$. The entries of $m$ are $u_i:v_i, i \in 1 .. n$, where $u_i$ is the value of the compile-time expression $k_i$ and $v_i$ is the value of the compile-time expression $e_i$.  The value of a constant map literal  \CONST{} $\{k_1:e_1\ldots k_n :e_n\}$ is defined as the value of a constant map literal \CONST{} $<\DYNAMIC{}, \DYNAMIC{}>\{k_1:e_1\ldots k_n :e_n\}$.
 
 Let $map_1 =$ \CONST{}$ <K, V>\{k_{11}:e_{11} \ldots k_{1n} :e_{1n}\}$ and  $map_2 =$  \CONST{}$ <J, U>\{k_{21}:e_{21} \ldots k_{2n} :e_{2n}\}$ be two constant map literals. Let the keys of $map_1$ and $map_2$ evaluate to  $s_{11} \ldots  s_{1n}$  and   $s_{21} \ldots  s_{2n}$ respectively, and let the elements of $map_1$ and $map_2$ evaluate to $o_{11} \ldots  o_{1n}$ and $o_{21} \ldots  o_{2n}$ respectively. Iff \code{identical($o_{1i}$, $o_{2i}$)}  and \code{identical($s_{1i}$, $s_{2i}$)} for $i \in 1.. n$, and $K = J, V = U$ then \code{identical($map_1$, $map_2$)}. 
 
 \commentary{In other words, constant map literals are canonicalized.}
 
 A runtime map literal $<K, V>\{k_1:e_1\ldots k_n :e_n\}$  is evaluated as follows:
 \begin{itemize}
 \item
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 {\bf logicalAndExpression:}
       equalityExpression (`\&\&' equalityExpression)*
 %      bitwiseOrExpression (`\&\&' bitwiseOrExpression)*
     .
  \end{grammar}
  
 A {\em logical boolean expression} is either an equality expression (\ref{equality}), or an invocation of a logical boolean operator on an expression $e_1$ with argument $e_2$.
  
-Evaluation of a logical boolean expression $b$ of the form $e_1 || e_2$ causes the evaluation of $e_1$ and then subjected to boolean conversion, yielding an object $o_1$; if $o_1$ is true, the result of evaluating $b$ is true, otherwise $e_2$ is evaluated to an object $o_2$, which is then subjected to boolean conversion (\ref{booleanConversion}) producing an object $r$, which is the value of $b$. 
+Evaluation of a logical boolean expression $b$ of the form $e_1 || e_2$ causes the evaluation of $e_1$ which is then  subjected to boolean conversion, yielding an object $o_1$; if $o_1$ is true, the result of evaluating $b$ is true, otherwise $e_2$ is evaluated to an object $o_2$, which is then subjected to boolean conversion (\ref{booleanConversion}) producing an object $r$, which is the value of $b$. 
 
-Evaluation of a logical boolean expression $b$ of the form $e_1 \&\& e_2$ causes the evaluation of $e_1$ and then subjected to boolean conversion, yielding an object $o_1$; if $o_1$ is not  true, the result of evaluating $b$ is false, otherwise $e_2$ is evaluated to an object $o_2$, which is then subjected to boolean conversion producing an object $r$, which is the value of $b$. 
+Evaluation of a logical boolean expression $b$ of the form $e_1 \&\& e_2$ causes the evaluation of $e_1$ which is then subjected to boolean conversion, yielding an object $o_1$; if $o_1$ is not  true, the result of evaluating $b$ is false, otherwise $e_2$ is evaluated to an object $o_2$, which is then subjected to boolean conversion producing an object $r$, which is the value of $b$. 
 
 A logical boolean expression $b$ of the form $e_1 \&\& e_2$ shows that a variable $v$ has type 
 $T$ if all of the following conditions hold:
 \begin{itemize}
 \item Either $e_1$ shows that $v$ has type $T$ or $e_2$ shows that $v$ has type $T$.
 \item $v$ is a local variable or formal parameter.
 \item The variable $v$ is not mutated in $e_2$ or within a closure.
 \end{itemize}
 
 Furthermore, if all of the following hold:
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 \item The names of compile time constant variables never use lower case letters. If they consist of multiple words, those words are separated by underscores. Examples: PI,  I\_AM\_A\_CONSTANT.
 \item The names of functions (including getters, setters, methods and local or library functions) and non-constant variables begin with a lowercase letter. If the name consists of multiple words, each  word (except the first) begins with an uppercase letter.  No other uppercase letters are used. Examples: camlCase, dart4TheWorld
 \item The names of types (including classes and type aliases) begin with an upper case letter.  If the name consists of multiple words, each  word  begins with an uppercase letter.  No other uppercase letters are used. Examples: CamlCase, Dart4TheWorld.
 \item The names of type variables are short (preferably single letter). Examples: T, S, K, V , E.
 \item The names of libraries or library prefixes never use upper case letters. If they consist of multiple words, those words are separated by underscores. Example: my\_favorite\_library.
 \end{itemize}
 }
 
 
 \end{document}