Fix wording for break and continue.

docs/language/dartLangSpec.tex

 \documentclass{article}
 \usepackage{epsfig}
 \usepackage{color}
 \usepackage{dart}
 \usepackage{bnf}
 \usepackage{hyperref}
 \usepackage{lmodern}
 \usepackage[T1]{fontenc}
 \newcommand{\code}[1]{{\sf #1}}
 \title{Dart Programming Language  Specification  \\
@@ skipping 6548 matching lines @@
 \LMHash{}
 The {\em break statement} consists of the reserved word \BREAK{} and an optional label (\ref{labels}).
 
 \begin{grammar}
 {\bf breakStatement:}
      \BREAK{} identifier? `{\escapegrammar ;}'
     .
  \end{grammar}
 
 \LMHash{}
-Let $s_b$ be a \BREAK{} statement. If $s_b$ is of the form  \code{\BREAK{} $L$;}, then let $s_E$ be the innermost labeled statement with label $L$ enclosing $s_b$. If $s_b$ is of the form \code{\BREAK{};},  then let $s_E$ be the innermost  \DO{} (\ref{do}), \FOR{} (\ref{for}), \SWITCH{} (\ref{switch}) or \WHILE{} (\ref{while}) statement enclosing  $s_b$. It is a compile-time error if no such statement $s_E$ exists within the innermost function in which  $s_b$ occurs.
+Let $s_b$ be a \BREAK{} statement.
+If $s_b$ is of the form \code{\BREAK{} $L$;},
+then let $s_E$ be the innermost labeled statement with label $L$ enclosing $s_b$.
+If $s_b$ is of the form \code{\BREAK{};},
+then let $s_E$ be the innermost \code{\AWAIT{} \FOR{}} (\ref{asynchronousFor-in}),
+\DO{} (\ref{do}), \FOR{} (\ref{for}), \SWITCH{} (\ref{switch})
+or \WHILE{} (\ref{while}) statement enclosing $s_b$.
+It is a compile-time error if no such statement $s_E$ exists within
+the innermost function in which $s_b$ occurs.
 
 \LMHash{}
 Execution of a \BREAK{} statement \code{\BREAK{} $L$;} breaks to the label $L$ (\ref{completion}).
 
 Execution of a \BREAK{} statement \code{\BREAK{};} breaks without a label (\ref{completion}).
 
 
 \subsection{ Continue}
 \LMLabel{continue}
 
 \LMHash{}
 The {\em continue statement} consists of the reserved word \CONTINUE{} and an optional label (\ref{labels}).
 
 \begin{grammar}
 {\bf continueStatement:}
     \CONTINUE{} identifier? `{\escapegrammar ;}'
         .
  \end{grammar}
 
 \LMHash{}
-Let $s_c$ be a \CONTINUE{} statement. If $s_c$ is of the form  \code{\CONTINUE{} $L$;}, then let $s_E$ be the innermost labeled \DO{} (\ref{do}), \FOR{} (\ref{for}) or \WHILE{} (\ref{while}) statement or case clause with label $L$ enclosing $s_c$. If $s_c$ is of the form \code{\CONTINUE{};}  then let $s_E$ be the innermost  \DO{} (\ref{do}), \FOR{} (\ref{for}) or \WHILE{} (\ref{while}) statement enclosing  $s_c$. It is a compile-time error if no such statement or case clause $s_E$ exists within the innermost function in which  $s_c$ occurs.
+Let $s_c$ be a \CONTINUE{} statement.
+If $s_c$ is of the form \code{\CONTINUE{} $L$;},
+then let $s_E$ be the innermost labeled \code{\AWAIT{} \FOR{}} (\ref{asynchronousFor-in}),
+\DO{} (\ref{do}), \FOR{} (\ref{for}), or \WHILE{} (\ref{while})
+statement or \SWITCH{} statement with a labeled case clause,
+which is labeled with $L$ and encloses $s_c$.
+If $s_c$ is of the form \code{\CONTINUE{};}
+then let $s_E$ be the innermost \code{\AWAIT{} \FOR{}} (\ref{asynchronousFor-in})
+\DO{} (\ref{do}), \FOR{} (\ref{for}), or \WHILE{} (\ref{while})
+statement enclosing $s_c$.
+It is a compile-time error if no such statement or case clause $s_E$ exists within the innermost function in which  $s_c$ occurs.

[Kevin Millikin (Google), 2017/06/27 11:55:10]

"case clause" ==> "switch statement", but it's redundant because if s_E is a
switch statement then it is definitely a statement.


I think the phrasing of this whole section is too complicated for what it says. 
I suggest not introducing the name $s_E$ for the thing in order to say that the
thing exists (and it doesn't really matter if it's the innermost one or not so
long as there is one).

I'd suggest something along the lines of:

If $s_c$ is of the form \code{\CONTINUE{} $L$;}, then it is a compile-time error
if $s_c$ is not enclosed in a labeled \code{\AWAIT{} \FOR{}} ....

 
 Execution of a \CONTINUE{} statement \code{\CONTINUE{} $L$;} continues to the label $L$ (\ref{completion}).
 
 Execution of a \CONTINUE{} statement \code{\CONTINUE{};} continues without a label (\ref{completion}).
 
 
 \subsection{ Yield and Yield-Each}
 \LMLabel{yieldAndYieldEach}
 
 \subsubsection{ Yield}
@@ skipping 1587 matching lines @@
 
 The invariant that each normative paragraph is associated with a line
 containing the text \LMHash{} should be maintained.  Extra occurrences
 of \LMHash{} can be added if needed, e.g., in order to make
 individual \item{}s in itemized lists addressable.  Each \LM.. command
 must occur on a separate line.  \LMHash{} must occur immediately
 before the associated paragraph, and \LMLabel must occur immediately
 after the associated \section{}, \subsection{} etc.
 
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