CWG2891 Normative status of implementation limits

Author: burblebee

source/intro.tex

@@ -723,15 +723,15 @@
 \item
 If a program contains no violations of the rules in
 \ref{lex} through \ref{\lastlibchapter} and \ref{depr},
-a conforming implementation shall,
-within its resource limits as described in \ref{implimits},
+a conforming implementation shall
 accept and correctly execute
 \begin{footnote}
 ``Correct execution'' can include undefined behavior
 and erroneous behavior, depending on
 the data being processed; see \ref{intro.defs} and~\ref{intro.execution}.
 \end{footnote}
-that program.
+that program,
+except when the implementation's limitations (see below) are exceeded.
 \item
 \indextext{behavior!undefined}%
 If a program contains a violation of a rule for which no diagnostic is required,
@@ -812,6 +812,13 @@
 described in \ref{lex} through \ref{cpp} and
 the subset of the library facilities described in \ref{compliance}.
 
+\pnum
+An implementation is encouraged to document its limitations in
+the size or complexity of the programs it can successfully process,
+if possible and where known.
+\ref{implimits} lists some quantities that can be subject to limitations and
+a potential minimum supported value for each quantity.
+
 \pnum
 A conforming implementation may have extensions (including
 additional library functions), provided they do not alter the

source/limits.tex

@@ -1,22 +1,11 @@
 %!TEX root = std.tex
-\normannex{implimits}{Implementation quantities}
+\infannex{implimits}{Implementation quantities}
 
 \pnum
-Because computers are finite, \Cpp{}  implementations are inevitably
-limited in the size of the programs they can successfully process.
-Every implementation shall
-document those limitations where known.
-This documentation may cite fixed limits where they
-exist, say how to compute variable limits as a function
-of available resources, or say that fixed limits do not exist
-or are unknown.
-
-\pnum
-The limits may constrain quantities
-that include those described below or others.
-The bracketed number following each quantity is recommended
-as the minimum for that quantity.
-However, these quantities are only guidelines and do not determine compliance.
+Implementations can exhibit limitations for various quantities;
+some possibilities are presented in the following list.
+The bracketed number following each quantity is
+a potential minimum value for that quantity.
 \begin{itemize}
 \item%
 Nesting levels of compound statements\iref{stmt.block},