%!TEX root = std.tex

% Definitions and redefinitions of special commands
%
% For macros that are likely to appear inside code blocks, we may provide a
% "macro length" correction value, which can be used to determine the effective
% column number where an emitted character appears, by adding the macro length,
% plus 2 for the escape-'@'s, plus 2 for the braces, to the real column number.
%
% For example:
%
% \newcommand{\foo[1]{#1}  % macro length: 4
%
% \begin{codeblock}
% int a = 10;         // comment on column 20
% int b = @\foo{x}@;          // comment also on effective column 20
%
% Here the real column of the second comment start is offset by 8 (4 + macro length).

%%--------------------------------------------------
%% Difference markups
%%--------------------------------------------------
\definecolor{addclr}{rgb}{0,.6,.6}
\definecolor{remclr}{rgb}{1,0,0}
\definecolor{noteclr}{rgb}{0,0,1}

\renewcommand{\added}[1]{\textcolor{addclr}{\uline{#1}}}
\newcommand{\removed}[1]{\textcolor{remclr}{\sout{#1}}}
\renewcommand{\changed}[2]{\removed{#1}\added{#2}}

\newcommand{\nbc}[1]{[#1]\ }
\newcommand{\addednb}[2]{\added{\nbc{#1}#2}}
\newcommand{\removednb}[2]{\removed{\nbc{#1}#2}}
\newcommand{\changednb}[3]{\removednb{#1}{#2}\added{#3}}
\newcommand{\remitem}[1]{\item\removed{#1}}

\newcommand{\ednote}[1]{\textcolor{noteclr}{[Editor's note: #1] }}

\newenvironment{addedblock}{\color{addclr}}{\color{black}}
\newenvironment{removedblock}{\color{remclr}}{\color{black}}

%%-------------------------------------------------------------
%% Grammar extraction.
%% Assumes that the output file \gramout is managed externally.
%%-------------------------------------------------------------
\makeatletter
\newcommand{\gramWrite}[1]{\protected@write\gramout{}{#1}}
\newcommand{\meaningbody}[1]{\expandafter\strip@prefix\meaning#1}
\makeatother

\newcommand{\gramSec}[2][]{\gramWrite{%
\string\rSec1\string[\string#1\string]\string{\string#2\string}}}

%%--------------------------------------------------
% Escaping for index entries. Replaces ! with "! throughout its argument.
%%--------------------------------------------------
\def\indexescape#1{\doindexescape#1\stopindexescape!\doneindexescape}
\def\doindexescape#1!{#1"!\doindexescape}
\def\stopindexescape#1\doneindexescape{}

%%--------------------------------------------------
%% Cross-references.
%%--------------------------------------------------
\newcommand{\addxref}[1]{%
 \hypertarget{#1}{}%
 \glossary[xrefindex]{\indexescape{#1}}{(\ref{\indexescape{#1}})}%
}

%%--------------------------------------------------
%% Sectioning macros.
% Each section has a depth, an automatically generated section
% number, a name, and a short tag.  The depth is an integer in
% the range [0,5].  (If it proves necessary, it wouldn't take much
% programming to raise the limit from 5 to something larger.)
%%--------------------------------------------------

% Set the xref label for a clause to be "Clause n", not just "n".
\makeatletter
\newcommand{\customlabel}[3]{%
\@bsphack \protected@write\@auxout{}{\string\newlabel{#1}{{#3}{\thepage}{}{#2.\thechapter}{}}} \@esphack%
}
\makeatother
\newcommand{\clauselabel}[1]{\customlabel{#1}{chapter}{Clause \thechapter}}
\newcommand{\annexlabel}[1]{\customlabel{#1}{appendix}{Annex \thechapter}}

% Use prefix "Annex" in the table of contents
\newcommand{\annexnumberlinebox}[2]{Annex #2\space}

% The basic sectioning command.  Example:
%    \Sec1[intro.scope]{Scope}
% defines a first-level section whose name is "Scope" and whose short
% tag is intro.scope.  The square brackets are mandatory.
\def\Sec#1[#2]#3{%
\addxref{#2}%
\ifcase#1\let\s=\chapter\let\l=\clauselabel
      \or\let\s=\section\let\l=\label
      \or\let\s=\subsection\let\l=\label
      \or\let\s=\subsubsection\let\l=\label
      \or\let\s=\paragraph\let\l=\label
      \or\let\s=\subparagraph\let\l=\label
      \fi%
\s[#3]{#3\hfill[#2]}\l{#2}%
}

% A convenience feature (mostly for the convenience of the Project
% Editor, to make it easy to move around large blocks of text):
% the \rSec macro is just like the \Sec macro, except that depths
% relative to a global variable, SectionDepthBase.  So, for example,
% if SectionDepthBase is 1,
%   \rSec1[temp.arg.type]{Template type arguments}
% is equivalent to
%   \Sec2[temp.arg.type]{Template type arguments}
\newcounter{SectionDepthBase}
\newcounter{SectionDepth}

\def\rSec#1[#2]#3{%
\setcounter{SectionDepth}{#1}
\addtocounter{SectionDepth}{\value{SectionDepthBase}}
\Sec{\arabic{SectionDepth}}[#2]{#3}}

%%--------------------------------------------------
% Bibliography
%%--------------------------------------------------
\newcommand{\supercite}[1]{\textsuperscript{\cite{#1}}}

%%--------------------------------------------------
% Indexing
%%--------------------------------------------------

% Layout of general index
\newcommand{\rSecindex}[2]{\section*{#2}\pdfbookmark[1]{#2}{pdf.idx.#1.#2}\label{idx.#1.#2}}

% locations
\newcommand{\indextext}[1]{\index[generalindex]{#1}}
\newcommand{\indexlibrary}[1]{\index[libraryindex]{#1}}
\newcommand{\indexhdr}[1]{\index[headerindex]{\idxhdr{#1}}}
\newcommand{\indexconcept}[1]{\index[conceptindex]{#1}}
\newcommand{\indexgram}[1]{\index[grammarindex]{#1}}

% Collation helper: When building an index key, replace all macro definitions
% in the key argument with a no-op for purposes of collation.
\newcommand{\nocode}[1]{#1}
\newcommand{\idxmname}[1]{\_\_#1\_\_}
\newcommand{\idxCpp}{C++}

% \indeximpldef synthesizes a collation key from the argument; that is, an
% invocation \indeximpldef{arg} emits an index entry `key@arg`, where `key`
% is derived from `arg` by replacing the following list of commands with their
% bare content. This allows, say, collating plain text and code.
\newcommand{\indeximpldef}[1]{%
\let\otextup\textup%
\let\textup\nocode%
\let\otcode\tcode%
\let\tcode\nocode%
\let\oexposid\exposid%
\let\exposid\nocode%
\let\ogrammarterm\grammarterm%
\let\grammarterm\nocode%
\let\omname\mname%
\let\mname\idxmname%
\let\oCpp\Cpp%
\let\Cpp\idxCpp%
\let\oBreakableUnderscore\BreakableUnderscore%  See the "underscore" package.
\let\BreakableUnderscore\textunderscore%
\edef\x{#1}%
\let\tcode\otcode%
\let\exposid\oexposid%
\let\grammarterm\gterm%
\let\mname\omname%
\let\Cpp\oCpp%
\let\BreakableUnderscore\oBreakableUnderscore%
\index[impldefindex]{\x@#1}%
\let\grammarterm\ogrammarterm%
\let\textup\otextup%
}

\newcommand{\indexdefn}[1]{\indextext{#1}}
\newcommand{\idxbfpage}[1]{\textbf{\hyperpage{#1}}}
\newcommand{\indexgrammar}[1]{\indextext{#1}\indexgram{#1|idxbfpage}}
% This command uses the "cooked" \indeximpldef command to emit index
% entries; thus they only work for simple index entries that do not contain
% special indexing instructions.
\newcommand{\impldef}[1]{\indeximpldef{#1}imple\-men\-ta\-tion-defined}
% \impldefplain passes the argument directly to the index, allowing you to
% use special indexing instructions (!, @, |).
\newcommand{\impldefplain}[1]{\index[impldefindex]{#1}implementation-defined}

% appearance
% avoid \tcode to avoid falling victim of \tcode redefinition in CodeBlockSetup
\newcommand{\idxcode}[1]{#1@\CodeStylex{#1}}
\newcommand{\idxconcept}[1]{#1@\CodeStylex{#1}}
\newcommand{\idxexposconcept}[1]{#1@\CodeStylex{\placeholder{#1}}}
\newcommand{\idxhdr}[1]{#1@\CodeStylex{<#1>}}
\newcommand{\idxgram}[1]{#1@\gterm{#1}}
\newcommand{\idxterm}[1]{#1@\term{#1}}
\newcommand{\idxxname}[1]{__#1@\xname{#1}}

% library index entries
\newcommand{\indexlibraryglobal}[1]{\indexlibrary{\idxcode{#1}}}
\newcommand{\indexlibrarymisc}[2]{\indexlibrary{#1!#2}}
\newcommand{\indexlibraryctor}  [1]{\indexlibrarymisc{\idxcode{#1}}{constructor}}
\newcommand{\indexlibrarydtor}  [1]{\indexlibrarymisc{\idxcode{#1}}{destructor}}
\newcommand{\indexlibraryzombie}[1]{\indexlibrarymisc{\idxcode{#1}}{zombie}}

% class member library index
\newcommand{\indexlibraryboth}[2]{\indexlibrarymisc{#1}{#2}\indexlibrarymisc{#2}{#1}}
\newcommand{\indexlibrarymember}[2]{\indexlibraryboth{\idxcode{#1}}{\idxcode{#2}}}
\newcommand{\indexlibrarymemberexpos}[2]{\indexlibraryboth{\idxcode{#1}}{#2@\exposid{#2}}}
\newcommand{\indexlibrarymemberx}[2]{\indexlibrarymisc{\idxcode{#1}}{\idxcode{#2}}}

\newcommand{\libglobal}[1]{\indexlibraryglobal{#1}#1}
\newcommand{\libmember}[2]{\indexlibrarymember{#1}{#2}#1}
\newcommand{\libspec}[2]{\indexlibrarymemberx{#1}{#2}#1}

% index for macros
% \libmacro is suitable for use directly in header synopses to add the macro
% to both the text and the library index. \libxmacro does the same, but
% prepends a well-rendered double underscore.
\newcommand{\libmacro}[1]{\indexlibraryglobal{#1}\CodeStylex{#1}}
\newcommand{\libxmacro}[1]{\indexlibraryglobal{\idxxname{#1}}\CodeStylex{\xname{#1}}}

% index for library headers
\newcommand{\libheaderx}[2]{\indexhdr{#1}\tcode{<#2>}}
\newcommand{\libheader}[1]{\libheaderx{#1}{#1}}
\newcommand{\indexheader}[1]{\index[headerindex]{\idxhdr{#1}|idxbfpage}}
\newcommand{\libheaderdef}[1]{\indexheader{#1}\tcode{<#1>}}
\newcommand{\libnoheader}[1]{\indextext{\idxhdr{#1}!absence thereof}\tcode{<#1>}}
\newcommand{\libheaderrefxx}[3]{\libheaderx{#1}{#2}\iref{#3}}
\newcommand{\libheaderrefx}[2]{\libheaderrefxx{#1}{#1}{#2}}
\newcommand{\libheaderref}[1]{\libheaderrefx{#1}{#1.syn}}
\newcommand{\libdeprheaderref}[1]{\libheaderrefx{#1}{depr.#1.syn}}

%%--------------------------------------------------
% General code style
%%--------------------------------------------------
\newcommand{\CodeStyle}{\ttfamily}
\newcommand{\CodeStylex}[1]{\texttt{\protect\frenchspacing #1}}
\makeatletter
% Append `\@` to restore proper sentence spacing in text mode. This insertion
% happens only during normal typesetting; it is suppressed for .idx generation.
\newcommand{\CodeStylexGuarded}[1]{\CodeStylex{#1\ifmmode\else\ifx\protect\@typeset@protect\@\fi\fi}}
\makeatother

\definecolor{grammar-gray}{gray}{0.2}

% General grammar style
\newcommand{\GrammarStylex}[1]{\textcolor{grammar-gray}{\textsf{\textit{#1}}}}

% Code and definitions embedded in text.
\newcommand{\tcode}[1]{\CodeStylexGuarded{#1}}
\newcommand{\term}[1]{\textit{#1}}
\newcommand{\gterm}[1]{\GrammarStylex{#1}}
\newcommand{\fakegrammarterm}[1]{\gterm{#1}}
\newcommand{\keyword}[1]{\texorpdfstring{\tcode{#1}\protect\indextext{\idxcode{#1}!keyword}}{#1}}                % macro length: 8
\newcommand{\grammarterm}[1]{\texorpdfstring{\protect\indexgram{\idxgram{#1}}\gterm{#1}}{#1}}
\newcommand{\grammartermnc}[1]{\indexgram{\idxgram{#1}}\gterm{#1\nocorr}}
\newcommand{\regrammarterm}[1]{\textit{#1}}
\newcommand{\placeholder}[1]{\textit{#1}}                                   % macro length: 12
\newcommand{\placeholdernc}[1]{\textit{#1\nocorr}}                          % macro length: 14
\newcommand{\exposid}[1]{\tcode{\placeholder{#1}}}                          % macro length: 8
\newcommand{\exposidnc}[1]{\tcode{\placeholdernc{#1}}\itcorr[-1]}           % macro length: 10
\newcommand{\defnxname}[1]{\indextext{\idxxname{#1}}\xname{#1}}
\newcommand{\defnlibxname}[1]{\indexlibrary{\idxxname{#1}}\xname{#1}}

% Non-compound defined term.
\newcommand{\defn}[1]{\defnx{#1}{#1}}
% Defined term with different index entry.
\newcommand{\defnx}[2]{\indexdefn{#2}\textit{#1}}
% Compound defined term with 'see' for primary term.
% Usage: \defnadj{trivial}{class}
\newcommand{\defnadj}[2]{\indextext{#1 #2|see{#2, #1}}\indexdefn{#2!#1}\textit{#1 #2}}
% Compound defined term with a different form for the primary noun.
% Usage: \defnadjx{scalar}{types}{type}
\newcommand{\defnadjx}[3]{\indextext{#1 #3|see{#3, #1}}\indexdefn{#3!#1}\textit{#1 #2}}

% Macros used for the grammar of std::format format specifications.
% FIXME: For now, keep the format grammar productions out of the index, since
% they conflict with the main grammar.
% Consider renaming these en masse (to fmt-* ?) to avoid this problem.
\newcommand{\fmtnontermdef}[1]{{\BnfNontermshape#1\itcorr}\textnormal{:}}
\newcommand{\fmtgrammarterm}[1]{\gterm{#1}}

%%--------------------------------------------------
%% allow line break if needed for justification
%%--------------------------------------------------
\newcommand{\brk}{\discretionary{}{}{}}

%%--------------------------------------------------
%% Macros for funky text
%%--------------------------------------------------
\newcommand{\Cpp}{\texorpdfstring{C\kern-0.05em\protect\raisebox{.35ex}{\textsmaller[2]{+\kern-0.05em+}}}{C++}}
\newcommand{\CppIII}{\Cpp{} 2003}
\newcommand{\CppXI}{\Cpp{} 2011}
\newcommand{\CppXIV}{\Cpp{} 2014}
\newcommand{\CppXVII}{\Cpp{} 2017}
\newcommand{\CppXX}{\Cpp{} 2020}
\newcommand{\CppXXIII}{\Cpp{} 2023}
\newcommand{\CppXXVI}{\Cpp{} 2026}
\newcommand{\IsoCUndated}{ISO/IEC 9899}
\newcommand{\IsoC}{\IsoCUndated{}:2024}
\newcommand{\IsoFloatUndated}{ISO/IEC 60559}
\newcommand{\IsoPosixUndated}{ISO/IEC/IEEE 9945}
\newcommand{\IsoPosix}{\IsoPosixUndated{}:2009}
\newcommand{\opt}[1]{#1\ensuremath{_\mathit{\color{black}opt}}}
\newcommand{\bigoh}[1]{\ensuremath{\mathscr{O}(#1)}}

% Make all tildes a little larger to avoid visual similarity with hyphens.
\renewcommand{\~}{\textasciitilde}
\let\OldTextAsciiTilde\textasciitilde
\renewcommand{\textasciitilde}{\protect\raisebox{-0.17ex}{\larger\OldTextAsciiTilde}}
\newcommand{\caret}{\char`\^}

%%--------------------------------------------------
%% States and operators
%%--------------------------------------------------
\newcommand{\state}[2]{\tcode{#1}\ensuremath{_{#2}}}
\newcommand{\bitand}{\ensuremath{\mathbin{\mathsf{bitand}}}}
\newcommand{\bitor}{\ensuremath{\mathbin{\mathsf{bitor}}}}
\newcommand{\xor}{\ensuremath{\mathbin{\mathsf{xor}}}}
\newcommand{\rightshift}{\ensuremath{\mathbin{\mathsf{rshift}}}}
\newcommand{\leftshift}[1]{\ensuremath{\mathbin{\mathsf{lshift}_{#1}}}}

%% Notes and examples
\newcommand{\noteintro}[1]{[\textit{#1}:}
\newcommand{\noteoutro}[1]{\textit{\,---\,#1}\kern.5pt]}

% \newnoteenvironment{ENVIRON}{BEGIN TEXT}{END TEXT}
% Creates a note-like environment beginning with BEGIN TEXT and
% ending with END TEXT. A counter with name ENVIRON indicates the
% number of this kind of note / example that has occurred in this
% subclause.
% Use tailENVIRON to avoid inserting a \par at the end.
\newcommand{\newnoteenvironment}[3]{
\newsubclausecounter{#1}
\newenvironment{tail#1}
{\par\small\penalty -200\stepcounter{#1}\noteintro{#2}}
{\noteoutro{#3}}
\newenvironment{#1}
{\begin{tail#1}}
% \small\par is for C++20 post-DIS compatibility
{\end{tail#1}\small\par\penalty -200}

}

\newnoteenvironment{note}{Note \arabic{note}}{end note}
\newnoteenvironment{example}{Example \arabic{example}}{end example}

\makeatletter
\let\footnote\@undefined
\global\newsavebox{\@tempfootboxa}   % must be global, to escape tables/figures
\newsavebox{\@templfootbox}
\newenvironment{footnote}{%
  \unskip\footnotemark%    no space before the mark
  \normalfont%
  \footnotesize%           text size for rendering the footnote text
  \begin{lrbox}{\@templfootbox}%       temporarily save to local box
}{%
  \end{lrbox}%
  \global\setbox\@tempfootboxa\hbox{\unhbox\@templfootbox}%  copy to global box
  \footnotetext{\unhbox\@tempfootboxa}%
}
\makeatother

%% Library function descriptions
\newcommand{\Fundescx}[1]{\textit{#1}}
\newcommand{\Fundesc}[1]{\Fundescx{#1}:\space}
\newcommand{\recommended}{\Fundesc{Recommended practice}}
\newcommand{\required}{\Fundesc{Required behavior}}
\newcommand{\constraints}{\Fundesc{Constraints}}
\newcommand{\mandates}{\Fundesc{Mandates}}
\newcommand{\constantwhen}{\Fundesc{Constant When}}
\newcommand{\expects}{\Fundesc{Preconditions}}
\newcommand{\hardexpects}{\Fundesc{Hardened preconditions}}
\newcommand{\effects}{\Fundesc{Effects}}
\newcommand{\ensures}{\Fundesc{Postconditions}}
\newcommand{\returns}{\Fundesc{Returns}}
\newcommand{\throws}{\Fundesc{Throws}}
\newcommand{\default}{\Fundesc{Default behavior}}
\newcommand{\complexity}{\Fundesc{Complexity}}
\newcommand{\remarks}{\Fundesc{Remarks}}
\newcommand{\errors}{\Fundesc{Error conditions}}
\newcommand{\sync}{\Fundesc{Synchronization}}
\newcommand{\implimits}{\Fundesc{Implementation limits}}
\newcommand{\result}{\Fundesc{Result}}
\newcommand{\returntype}{\Fundesc{Return type}}
\newcommand{\ctype}{\Fundesc{Type}}
\newcommand{\templalias}{\Fundesc{Alias template}}

%% Cross-reference
\newcommand{\xref}[1]{\textsc{See also:}\space #1}
\newcommand{\xrefc}[1]{\xref{\IsoC{}, #1}}
\newcommand{\termref}[3]{\textit{#2}{#3}\iref{#1}} % in Clause 3

%% Inline comma-separated parenthesized references
\ExplSyntaxOn
\NewDocumentCommand \iref { m } {
  \clist_set:Nx \l_tmpa_clist { #1 }
  \nolinebreak[3] ~ (
  \clist_map_inline:Nn \l_tmpa_clist {
    \clist_put_right:Nn \g_tmpa_clist { \ref{##1} }
  }
  \clist_use:Nn \g_tmpa_clist { ,~ }
  )
  \clist_clear:N \g_tmpa_clist
}
\ExplSyntaxOff

%% Inline non-parenthesized table reference (override memoir's \tref)
\providecommand{\tref}{}
\renewcommand{\tref}[1]{\hyperref[tab:#1]{\tablerefname \nolinebreak[3] \ref*{tab:#1}}}
%% Inline non-parenthesized figure reference (override memoir's \fref)
\providecommand{\fref}{}
\renewcommand{\fref}[1]{\hyperref[fig:#1]{\figurerefname \nolinebreak[3] \ref*{fig:#1}}}

%% NTBS, etc.
\verbtocs{\StrTextsmaller}|\textsmaller[1]{|
\verbtocs{\StrTextsc}|\textsc{|
\verbtocs{\StrClosingbrace}|}|
\newcommand{\ucode}[1]{%
  \textsc{u}%
  \textsmaller[2]{\kern-0.05em\protect\raisebox{.25ex}{+}}%
  \begingroup%
  \def\temp{#1}%
  \StrSubstitute{\temp}{0}{X0Z}[\temp]%
  \StrSubstitute{\temp}{1}{X1Z}[\temp]%
  \StrSubstitute{\temp}{2}{X2Z}[\temp]%
  \StrSubstitute{\temp}{3}{X3Z}[\temp]%
  \StrSubstitute{\temp}{4}{X4Z}[\temp]%
  \StrSubstitute{\temp}{5}{X5Z}[\temp]%
  \StrSubstitute{\temp}{6}{X6Z}[\temp]%
  \StrSubstitute{\temp}{7}{X7Z}[\temp]%
  \StrSubstitute{\temp}{8}{X8Z}[\temp]%
  \StrSubstitute{\temp}{9}{X9Z}[\temp]%
  \StrSubstitute{\temp}{a}{YaZ}[\temp]%
  \StrSubstitute{\temp}{b}{YbZ}[\temp]%
  \StrSubstitute{\temp}{c}{YcZ}[\temp]%
  \StrSubstitute{\temp}{d}{YdZ}[\temp]%
  \StrSubstitute{\temp}{e}{YeZ}[\temp]%
  \StrSubstitute{\temp}{f}{YfZ}[\temp]%
  \StrSubstitute{\temp}{X}{\StrTextsmaller}[\temp]%
  \StrSubstitute{\temp}{Y}{\StrTextsc}[\temp]%
  \StrSubstitute{\temp}{Z}{\StrClosingbrace}[\temp]%
  \tokenize\temp{\temp}%
  \temp%
  \endgroup%
}
\newcommand{\uname}[1]{\textsc{#1}}
\newcommand{\unicode}[2]{\ucode{#1} \uname{#2}}
\newcommand{\UAX}[1]{\texorpdfstring{UAX~\textsmaller[1]{\raisebox{0.35ex}{\#}}#1}{UAX \##1}}
\newcommand{\NTS}[1]{\textsc{#1}}
\newcommand{\ntbs}{\NTS{ntbs}}
\newcommand{\ntmbs}{\NTS{ntmbs}}
% The following are currently unused:
% \newcommand{\ntwcs}{\NTS{ntwcs}}
% \newcommand{\ntcxvis}{\NTS{ntc16s}}
% \newcommand{\ntcxxxiis}{\NTS{ntc32s}}

%% Code annotations
\newcommand{\EXPO}[1]{\textit{#1}}
\newcommand{\expos}{\EXPO{exposition only}}
\newcommand{\impdef}{\EXPO{implementation-defined}}
\newcommand{\impdefnc}{\EXPO{implementation-defined\nocorr}}
\newcommand{\impdefx}[1]{\indeximpldef{#1}\EXPO{implementation-defined}}
\newcommand{\notdef}{\EXPO{not defined}}

\newcommand{\UNSP}[1]{\textit{\texttt{#1}}}
\newcommand{\UNSPnc}[1]{\textit{\texttt{#1}\nocorr}}
\newcommand{\unspec}{\UNSP{unspecified}}
\newcommand{\unspecnc}{\UNSPnc{unspecified}}
\newcommand{\unspecbool}{\UNSP{unspecified-bool-type}}
\newcommand{\seebelow}{\UNSP{see below}}      % macro length: 0
\newcommand{\seebelownc}{\UNSPnc{see below}}  % macro length: 2
\newcommand{\seeabove}{\UNSP{see above}}      % macro length: 0
\newcommand{\seeabovenc}{\UNSPnc{see above}}  % macro length: 2
\newcommand{\unspecuniqtype}{\UNSP{unspecified unique type}}
\newcommand{\unspecalloctype}{\UNSP{unspecified allocator type}}

%% Convenience macro for double carets in expressions,
%% particularly within \tcode.
\newcommand{\reflexpr}[1]{\caret\caret#1}

%% Manual insertion of italic corrections, for aligning in the presence
%% of the above annotations.
\newlength{\itcorrwidth}
\newlength{\itletterwidth}
\newcommand{\itcorr}[1][]{%
 \settowidth{\itcorrwidth}{\textit{x\/}}%
 \settowidth{\itletterwidth}{\textit{x\nocorr}}%
 \addtolength{\itcorrwidth}{-1\itletterwidth}%
 \makebox[#1\itcorrwidth]{}%
}

%% Double underscore
\newcommand{\ungap}{\kern.5pt}
\newcommand{\unun}{\textunderscore\ungap\textunderscore}
\newcommand{\xname}[1]{\tcode{\unun\ungap#1}}
\newcommand{\mname}[1]{\tcode{\unun\ungap#1\ungap\unun}}

%% An elided code fragment, /* ... */, that is formatted as code.
%% (By default, listings typeset comments as body text.)
%% Produces 9 output characters.
\newcommand{\commentellip}{\tcode{/* ...\ */}}

%% Concepts
\newcommand{\oldconceptname}[1]{Cpp17#1}
\newcommand{\oldconcept}[1]{\textit{\oldconceptname{#1}}}
\newcommand{\defnoldconcept}[1]{\indexdefn{\idxoldconcept{#1}}\oldconcept{#1}}
\newcommand{\idxoldconcept}[1]{\oldconceptname{#1}@\oldconcept{#1}}
% FIXME: A "new" oldconcept (added after C++17),
% which doesn't get a Cpp17 prefix.
\newcommand{\newoldconcept}[1]{\textit{#1}}
\newcommand{\defnnewoldconcept}[1]{\indexdefn{\idxnewoldconcept{#1}}\newoldconcept{#1}}
\newcommand{\idxnewoldconcept}[1]{#1@\newoldconcept{#1}}

\newcommand{\cname}[1]{\tcode{#1}}
\newcommand{\ecname}[1]{\tcode{\placeholder{#1}}}
\newcommand{\libconceptx}[2]{\cname{#1}\indexconcept{\idxconcept{#2}}}
\newcommand{\libconcept}[1]{\libconceptx{#1}{#1}}
\newcommand{\deflibconcept}[1]{\cname{#1}\indexlibrary{\idxconcept{#1}}\indexconcept{\idxconcept{#1}|idxbfpage}}
\newcommand{\exposconceptx}[2]{\ecname{#1}\indexconcept{\idxexposconcept{#2}}}
\newcommand{\exposconcept}[1]{\exposconceptx{#1}{#1}}
\newcommand{\exposconceptnc}[1]{\indexconcept{\idxexposconcept{#1}}\ecname{#1}\itcorr[-1]}               % macro length: 15
\newcommand{\defexposconcept}[1]{\ecname{#1}\indexconcept{\idxexposconcept{#1}|idxbfpage}}               % macro length: 16
\newcommand{\defexposconceptnc}[1]{\ecname{#1}\indexconcept{\idxexposconcept{#1}|idxbfpage}\itcorr[-1]}  % macro length: 18

%% Ranges
\newcommand{\Range}[4]{\ensuremath{#1}\tcode{#3}\ensuremath{,}\,\penalty2000{}\tcode{#4}\ensuremath{#2}}
\newcommand{\crange}[2]{\Range{[}{]}{#1}{#2}}
\newcommand{\brange}[2]{\Range{(}{]}{#1}{#2}}
\newcommand{\orange}[2]{\Range{(}{)}{#1}{#2}}
\newcommand{\range}[2]{\Range{[}{)}{#1}{#2}}
\newcommand{\countedrange}[2]{$\tcode{#1} + \range{0}{#2}$}

%% Change descriptions
\newcommand{\diffhead}[1]{\textbf{#1:}\space}
\newcommand{\diffdef}[1]{\ifvmode\else\hfill\break\fi\diffhead{#1}}
\ExplSyntaxOn
\NewDocumentCommand \diffref { m } {
  \clist_set:Nx \l_tmpa_clist { #1 }
  \pnum
  \int_compare:nTF { \clist_count:N \l_tmpa_clist < 2 } {
    \textbf{Affected~subclause:} ~
  } {
    \textbf{Affected~subclauses:} ~
  }
  \clist_map_inline:Nn \l_tmpa_clist {
    \clist_put_right:Nn \g_tmpa_clist { \ref{##1} }
  }
  \clist_use:Nnnn \g_tmpa_clist { ~and~ } { ,~ } { ,~and~ }
  \clist_clear:N \g_tmpa_clist
}
\cs_set_eq:NN \diffrefs \diffref
\ExplSyntaxOff
% \nodiffref swallows a following \change and removes the preceding line break.
\def\nodiffref\change{\pnum
\diffhead{Change}}
\newcommand{\change}{\diffdef{Change}}
\newcommand{\rationale}{\diffdef{Rationale}}
\newcommand{\effect}{\diffdef{Effect on original feature}}
\newcommand{\effectafteritemize}{\diffhead{Effect on original feature}}
\newcommand{\difficulty}{\diffdef{Difficulty of converting}}
\newcommand{\howwide}{\diffdef{How widely used}}

%% Miscellaneous
\newcommand{\stage}[1]{\item[Stage #1:]}
\newcommand{\doccite}[1]{\textit{#1}}
\newcommand{\cvqual}[1]{\textit{#1}}
\newcommand{\cv}{\ifmmode\mathit{cv}\else\cvqual{cv}\fi}
\newcommand{\numconst}[1]{\textsl{#1}}
\newcommand{\logop}[1]{\textsc{#1}}
\DeclareMathOperator{\mullo}{mullo}
\DeclareMathOperator{\mulhi}{mulhi}
\newcommand{\cedef}{\mathrel{\mathop:}=} % "colon-equals definition"

%%--------------------------------------------------
%% Environments for code listings.
%%--------------------------------------------------

% We use the 'listings' package, with some small customizations.
% The most interesting customization: all TeX commands are available
% within comments. Comments are set in italics, keywords and strings
% don't get special treatment.

\lstset{language=C++,
        basicstyle=\small\CodeStyle,
        keywordstyle=,
        stringstyle=,
        xleftmargin=1em,
        showstringspaces=false,
        commentstyle=\itshape\rmfamily,
        columns=fullflexible,
        keepspaces=true,
        texcl=true}

% Our usual abbreviation for 'listings'.  Comments are in
% italics.  Arbitrary TeX commands can be used if they're
% surrounded by @ signs.
\newcommand{\CodeBlockSetup}{%
\lstset{escapechar=@, aboveskip=\parskip, belowskip=0pt,
        midpenalty=500, endpenalty=-50,
        emptylinepenalty=-250, semicolonpenalty=0,upquote=true}%
\renewcommand{\tcode}[1]{\textup{\CodeStylexGuarded{##1}}}
\renewcommand{\term}[1]{\textit{##1}}%
\renewcommand{\grammarterm}[1]{\gterm{##1}}%
}

\lstnewenvironment{codeblock}{\CodeBlockSetup}{}

\lstnewenvironment{codeblocktu}[1]{%
\lstset{title={%\parabullnum{Bullets1}{0pt}
#1:}}\CodeBlockSetup}{}

% An environment for command / program output that is not C++ code.
\lstnewenvironment{outputblock}{\lstset{escapechar=@, language=}}{}

% A code block in which single-quotes are digit separators
% rather than character literals.
\lstnewenvironment{codeblockdigitsep}{
 \CodeBlockSetup
 \lstset{deletestring=[b]{'}}
}{}

% Permit use of '@' inside codeblock blocks (don't ask)
\makeatletter
\newcommand{\atsign}{@}
\makeatother

%%--------------------------------------------------
%% Formulae
%%--------------------------------------------------

% usage: \begin{formula}{XREF}
\newenvironment{formula}[1]
{\begin{equation}\label{eq:#1}}
{\end{equation}}

\renewcommand{\eqref}[1]{Formula \nolinebreak[3] \hyperref[eq:#1]{\ref*{eq:#1}}}

%%--------------------------------------------------
%% Indented text
%%--------------------------------------------------
\newenvironment{indented}[1][]
{\begin{indenthelper}[#1]\item\relax}
{\end{indenthelper}}

%%--------------------------------------------------
%% Library item descriptions
%%--------------------------------------------------
\lstnewenvironment{itemdecl}
{
 \lstset{escapechar=@,
 xleftmargin=0em,
 midpenalty=3000,
 semicolonpenalty=-50,
 endpenalty=2000,
 aboveskip=2ex,
 belowskip=0ex	% leave this alone: it keeps these things out of the
				% footnote area
 }%
 \renewcommand{\tcode}[1]{\textup{\CodeStylexGuarded{##1}}}
}
{
}

\newenvironment{itemdescr}
{
 \begin{indented}[beginpenalty=3000, endpenalty=-300]}
{
 \end{indented}
}


%%--------------------------------------------------
%% Bnf environments
%%--------------------------------------------------
\newlength{\BnfIndent}
\setlength{\BnfIndent}{\leftmargini}
\newlength{\BnfInc}
\setlength{\BnfInc}{\BnfIndent}
\newlength{\BnfRest}
\setlength{\BnfRest}{2\BnfIndent}
\newcommand{\BnfNontermshape}{%
  \small%
  \color{grammar-gray}%
  % The color setting inserts a \pdfcolorstack entry into the vertical list,
  % breaking the connection of the \penalty entry from a preceding heading
  % with the \glue entries that precede the grammar snippet.
  % Add a penalty here that prevents making those \glue entries page-breaking
  % opportunities.
  \penalty10000%
  \sffamily%
  \itshape}
\newcommand{\BnfReNontermshape}{\small\rmfamily\itshape}
\newcommand{\BnfTermshape}{\small\ttfamily\upshape}

\newenvironment{bnfbase}
 {
 \newcommand{\nontermdef}[1]{{\BnfNontermshape##1\itcorr}\indexgrammar{\idxgram{##1}}\textnormal{:}}
 \newcommand{\terminal}[1]{{\BnfTermshape ##1}}
 \renewcommand{\keyword}[1]{\terminal{##1}\indextext{\idxcode{##1}!keyword}}
 \renewcommand{\exposid}[1]{\terminal{\textit{##1}}}
 \renewcommand{\placeholder}[1]{\textrm{\textit{##1}}}
 \newcommand{\descr}[1]{\textnormal{##1}}
 \newcommand{\bnfindent}{\hspace*{\bnfindentfirst}}
 \newcommand{\bnfindentfirst}{\BnfIndent}
 \newcommand{\bnfindentinc}{\BnfInc}
 \newcommand{\bnfindentrest}{\BnfRest}
 \newcommand{\br}{\hfill\\*}
 \widowpenalties 1 10000
 \frenchspacing
 }
 {
 \nonfrenchspacing
 }

% "ncbnf" is the non-copied "base" versions of the bnf environment;
% instances of the full "bnf" environment is copied to the grammar
% extraction file.
% (Similarly for "ncsimplebnf", though in fact we never extract any
% hypothetical "simplebnf" environments.)
\newenvironment{ncsimplebnf}
{
 \begin{bnfbase}
 \BnfNontermshape
 \begin{indented}[before*=\setlength{\rightmargin}{-\leftmargin}]
}
{
 \end{indented}
 \end{bnfbase}
}

\newenvironment{ncbnf}
{
 \begin{bnfbase}
 \begin{bnflist}
 \BnfNontermshape
 \item\relax
}
{
 \end{bnflist}
 \end{bnfbase}
}

% The regex grammar is never copied.
\newenvironment{ncrebnf}
{
 \begin{bnfbase}
 \newcommand{\renontermdef}[1]{{\BnfReNontermshape##1\itcorr}\,\textnormal{::}}
 \begin{bnflist}
 \BnfReNontermshape
 \item\relax
}
{
 \end{bnflist}
 \end{bnfbase}
}

\NewEnviron{bnf}{\begin{ncbnf}%
\BODY%
\gramWrite{\string\begin{ncbnf}\meaningbody\BODY\string\end{ncbnf}}%
\end{ncbnf}}{}

%%--------------------------------------------------
%% Environment for imported graphics
%%--------------------------------------------------
% usage: \begin{importgraphic}{CAPTION}{TAG}{FILE}\end{importgraphic}
%        \importexample[VERTICAL OFFESET]{FILE}
%
% The filename is relative to the source/assets directory.

\newenvironment{importgraphic}[3]
{%
\newcommand{\cptn}{#1}
\newcommand{\lbl}{#2}
\begin{figure}[htp]\centering%
\includegraphics[scale=.35]{assets/#3}
}
{
\caption{\cptn \quad [fig:\lbl]}\label{fig:\lbl}%
\end{figure}}

\newcommand{\importexample}[2][-0.9pt]{\raisebox{#1}{\includegraphics{assets/#2}}}

%%--------------------------------------------------
%% Definitions section for "Terms and definitions"
%%--------------------------------------------------
\newcommand{\nocontentsline}[3]{}
\newcommand{\definition}[2]{%
\addxref{#2}%
\let\oldcontentsline\addcontentsline%
\let\addcontentsline\nocontentsline%
\ifcase\value{SectionDepth}
         \let\s=\section
      \or\let\s=\subsection
      \or\let\s=\subsubsection
      \or\let\s=\paragraph
      \or\let\s=\subparagraph
      \fi%
\s[#1]{\hfill[#2]}\vspace{-.3\onelineskip}\label{#2} \textbf{#1}\\*%
\let\addcontentsline\oldcontentsline%
}
\newcommand{\defncontext}[1]{\textlangle#1\textrangle}
\newnoteenvironment{defnote}{Note \arabic{defnote} to entry}{end note}