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(Grammar Outline): Document // comments.

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(Symbols): Document that trigraphs have no special meaning in Bison,
nor is backslash-newline allowed.
(Actions): Document that trigraphs have no special meaning.
This commit is contained in:
Paul Eggert
2002-11-03 08:40:39 +00:00
parent 5389a5bff4
commit 2bfc2e2a7d
1 changed files with 16 additions and 5 deletions
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21
doc/bison.texinfo
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@@ -2212,6 +2212,8 @@ appropriate delimiters:
@end example @end example
Comments enclosed in @samp{/* @dots{} */} may appear in any of the sections. Comments enclosed in @samp{/* @dots{} */} may appear in any of the sections.
As a @acronym{GNU} extension, @samp{//} introduces a comment that
continues until end of line.
@menu @menu
* Prologue:: Syntax and usage of the prologue. * Prologue:: Syntax and usage of the prologue.
@@ -2360,7 +2362,9 @@ All the usual escape sequences used in character literals in C can be
used in Bison as well, but you must not use the null character as a used in Bison as well, but you must not use the null character as a
character literal because its numeric code, zero, signifies character literal because its numeric code, zero, signifies
end-of-input (@pxref{Calling Convention, ,Calling Convention end-of-input (@pxref{Calling Convention, ,Calling Convention
for @code{yylex}}). for @code{yylex}}). Also, unlike standard C, trigraphs have no
special meaning in Bison character literals, nor is backslash-newline
allowed.
@item @item
@cindex string token @cindex string token
@@ -2387,9 +2391,10 @@ does not enforce this convention, but if you depart from it, people who
read your program will be confused. read your program will be confused.
All the escape sequences used in string literals in C can be used in All the escape sequences used in string literals in C can be used in
Bison as well. A literal string token must contain two or more Bison as well. However, unlike Standard C, trigraphs have no special
characters; for a token containing just one character, use a character meaning in Bison string literals, nor is backslash-newline allowed. A
token (see above). literal string token must contain two or more characters; for a token
containing just one character, use a character token (see above).
@end itemize @end itemize
How you choose to write a terminal symbol has no effect on its How you choose to write a terminal symbol has no effect on its
@@ -2691,7 +2696,13 @@ is to compute a semantic value for the grouping built by the rule from the
semantic values associated with tokens or smaller groupings. semantic values associated with tokens or smaller groupings.
An action consists of C statements surrounded by braces, much like a An action consists of C statements surrounded by braces, much like a
compound statement in C@. It can be placed at any position in the rule; compound statement in C@. An action can contain any sequence of C
statements. Bison does not look for trigraphs, though, so if your C
code uses trigraphs you should ensure that they do not affect the
nesting of braces or the boundaries of comments, strings, or character
literals.
An action can be placed at any position in the rule;
it is executed at that position. Most rules have just one action at the it is executed at that position. Most rules have just one action at the
end of the rule, following all the components. Actions in the middle of end of the rule, following all the components. Actions in the middle of
a rule are tricky and used only for special purposes (@pxref{Mid-Rule a rule are tricky and used only for special purposes (@pxref{Mid-Rule