[cpp.replace.general] Rephrase function-like macro invocations

jensmaurer · jensmaurer · commit 5cb8204df1c8 · 2021-10-22T23:15:21.000+02:00
using the new grammar non-terminal pp-balanced-token-seq.
diff --git a/source/preprocessor.tex b/source/preprocessor.tex
@@ -987,18 +987,6 @@
 There shall be whitespace between the identifier and the replacement list
 in the definition of an object-like macro.
 
-\pnum
-If the \grammarterm{identifier-list} in the macro definition does not end with
-an ellipsis, the number of arguments (including those arguments consisting
-of no preprocessing tokens)
-in an invocation of a function-like macro shall
-equal the number of parameters in the macro definition.
-Otherwise, there shall be at least as many arguments in the invocation as there are
-parameters in the macro definition (excluding the \tcode{...}). There
-shall exist a
-\tcode{)}
-preprocessing token that terminates the invocation.
-
 \pnum
 \indextext{__va_args__@\mname{VA_ARGS}}%
 \indextext{__va_opt__@\mname{VA_OPT}}%
@@ -1068,6 +1056,18 @@
 \end{codeblock}
 \end{example}
 
+\begin{bnf}
+\nontermdef{pp-balanced-token}\br
+    \textnormal{any} preprocessing-token \textnormal{other than \terminal{(} or \terminal{)}}\br
+    \terminal{(} \opt{pp-balanced-token-seq} \terminal{)}
+\end{bnf}
+
+\begin{bnf}
+\nontermdef{pp-balanced-token-seq}\br
+    pp-balanced-token\br
+    pp-balanced-token pp-balanced-token-seq
+\end{bnf}
+
 \pnum
 A preprocessing directive of the form
 \begin{ncsimplebnf}
@@ -1081,37 +1081,53 @@
 The parameters
 \indextext{parameter!macro}%
 are specified by the optional list of identifiers.
-Each subsequent instance of the function-like macro name followed by a
-\tcode{(}
-as the next preprocessing token
-introduces the sequence of preprocessing tokens that is replaced
-by the replacement list in the definition
-(an invocation of the macro).
-\indextext{invocation!macro}%
-The replaced sequence of preprocessing tokens is terminated by the matching
-\tcode{)}
-preprocessing token, skipping intervening matched pairs of left and
-right parenthesis preprocessing tokens.
-Within the sequence of preprocessing tokens making up an invocation
-of a function-like macro,
-new-line is considered a normal whitespace character.
 
 \pnum
+\indextext{invocation!macro}%
 \indextext{macro!function-like!arguments}%
-The sequence of preprocessing tokens
-bounded by the outside-most matching parentheses
-forms the list of arguments for the function-like macro.
-The individual arguments within the list
-are separated by comma preprocessing tokens,
-but comma preprocessing tokens between matching
-inner parentheses do not separate arguments.
-If there are sequences of preprocessing tokens within the list of
-arguments that would otherwise act as preprocessing directives,
+Each instance of a function-like macro name
+followed by a \tcode{(} as the next preprocessing token
+shall be a function-like macro invocation of the form:
+\begin{ncsimplebnf}
+identifier \terminal{(} \opt{pp-balanced-token-seq} \terminal{)}
+\end{ncsimplebnf}
+Within the sequence of preprocessing tokens
+making up an invocation of a function-like macro,
+new-line is considered a normal whitespace character.
+The arguments of the macro invocation are
+the sequences of \grammarterm{pp-balanced-token}s
+separated by comma preprocessing tokens.
+If the \grammarterm{identifier-list} in the macro definition
+does not end with an ellipsis,
+the number of arguments
+(including those arguments consisting of no \grammarterm{pp-balanced-token}s)
+shall equal the number of parameters in the macro definition.
+Otherwise, there shall be at least as many arguments in the invocation
+as there are parameters in the macro definition (excluding the \tcode{...}).
+If there are sequences of preprocessing tokens within the list of arguments
+that would otherwise act as preprocessing directives,
 \begin{footnote}
-A \grammarterm{conditionally-supported-directive} is a preprocessing directive regardless of whether the implementation supports it.
+A \grammarterm{conditionally-supported-directive} is a preprocessing directive
+regardless of whether the implementation supports it.
 \end{footnote}
 the behavior is undefined.
 
+\pnum
+\indextext{macro!function-like!arguments}%
+If there is a \tcode{...} immediately preceding the \tcode{)} in the
+function-like macro
+definition, then the trailing arguments (if any), including any separating comma preprocessing
+tokens, are merged to form a single item: the \defn{variable arguments}. The number of
+arguments so combined is such that, following merger, the number of arguments is
+either equal to or
+one more than the number of parameters in the macro definition (excluding the
+\tcode{...}).
+
+\pnum
+Each function-like macro invocation
+is replaced by the replacement list in the macro definition,
+after performing argument substitution as described in \ref{cpp.subst}.
+
 \pnum
 \begin{example}
 The following defines a function-like
@@ -1133,25 +1149,14 @@
 the resulting expression are bound properly.
 \end{example}
 
-\pnum
-\indextext{macro!function-like!arguments}%
-If there is a \tcode{...} immediately preceding the \tcode{)} in the
-function-like macro
-definition, then the trailing arguments (if any), including any separating comma preprocessing
-tokens, are merged to form a single item: the \defn{variable arguments}. The number of
-arguments so combined is such that, following merger, the number of arguments is
-either equal to or
-one more than the number of parameters in the macro definition (excluding the
-\tcode{...}).
-
 \rSec2[cpp.subst]{Argument substitution}%
 \indextext{macro!argument substitution}%
 \indextext{argument substitution|see{macro, argument substitution}}%
 
 \indextext{__va_opt__@\mname{VA_OPT}}%
 \begin{bnf}
 \nontermdef{va-opt-replacement}\br
-    \terminal{\mname{VA_OPT} (} \opt{pp-tokens} \terminal{)}
+    \terminal{\mname{VA_OPT} (} \opt{pp-balanced-token-seq} \terminal{)}
 \end{bnf}
 
 \pnum
