cpp.texi: Replace "stringify"/"stringification" with C standard terminology...
2017-02-11 Sandra Loosemore <sandra@codesourcery.com> gcc/ * doc/cpp.texi: Replace "stringify"/"stringification" with C standard terminology "stringize"/"stringizing" throughout. * doc/cppinternals.texi: Likewise. From-SVN: r245371
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Sandra Loosemore
Sandra Loosemore
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3 changed files with 40 additions and 34 deletions
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@ -1,3 +1,9 @@
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2017-02-11 Sandra Loosemore <sandra@codesourcery.com>
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* doc/cpp.texi: Replace "stringify"/"stringification" with C
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standard terminology "stringize"/"stringizing" throughout.
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* doc/cppinternals.texi: Likewise.
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2017-02-11 Sandra Loosemore <sandra@codesourcery.com>
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* doc/extend.texi: Fix some spelling mistakes and typos.
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@ -119,7 +119,7 @@ Macros
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* Object-like Macros::
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* Function-like Macros::
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* Macro Arguments::
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* Stringification::
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* Stringizing::
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* Concatenation::
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* Variadic Macros::
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* Predefined Macros::
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@ -1155,7 +1155,7 @@ macros when you are compiling C++.
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* Object-like Macros::
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* Function-like Macros::
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* Macro Arguments::
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* Stringification::
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* Stringizing::
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* Concatenation::
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* Variadic Macros::
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* Predefined Macros::
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@ -1453,9 +1453,9 @@ their corresponding actual arguments.
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foo(bar) @expansion{} bar, "x"
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@end smallexample
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@node Stringification
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@section Stringification
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@cindex stringification
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@node Stringizing
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@section Stringizing
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@cindex stringizing
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@cindex @samp{#} operator
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Sometimes you may want to convert a macro argument into a string
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@ -1464,16 +1464,16 @@ can use the @samp{#} preprocessing operator instead. When a macro
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parameter is used with a leading @samp{#}, the preprocessor replaces it
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with the literal text of the actual argument, converted to a string
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constant. Unlike normal parameter replacement, the argument is not
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macro-expanded first. This is called @dfn{stringification}.
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macro-expanded first. This is called @dfn{stringizing}.
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There is no way to combine an argument with surrounding text and
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stringify it all together. Instead, you can write a series of adjacent
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string constants and stringified arguments. The preprocessor will
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replace the stringified arguments with string constants. The C
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compiler will then combine all the adjacent string constants into one
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stringize it all together. Instead, you can write a series of adjacent
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string constants and stringized arguments. The preprocessor
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replaces the stringized arguments with string constants. The C
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compiler then combines all the adjacent string constants into one
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long string.
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Here is an example of a macro definition that uses stringification:
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Here is an example of a macro definition that uses stringizing:
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@smallexample
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@group
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@ -1489,7 +1489,7 @@ WARN_IF (x == 0);
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@noindent
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The argument for @code{EXP} is substituted once, as-is, into the
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@code{if} statement, and once, stringified, into the argument to
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@code{if} statement, and once, stringized, into the argument to
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@code{fprintf}. If @code{x} were a macro, it would be expanded in the
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@code{if} statement, but not in the string.
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@ -1498,24 +1498,24 @@ write @code{WARN_IF (@var{arg});}, which the resemblance of
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@code{WARN_IF} to a function would make C programmers want to do; see
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@ref{Swallowing the Semicolon}.
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Stringification in C involves more than putting double-quote characters
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Stringizing in C involves more than putting double-quote characters
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around the fragment. The preprocessor backslash-escapes the quotes
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surrounding embedded string constants, and all backslashes within string and
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character constants, in order to get a valid C string constant with the
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proper contents. Thus, stringifying @code{@w{p = "foo\n";}} results in
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proper contents. Thus, stringizing @code{@w{p = "foo\n";}} results in
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@t{@w{"p = \"foo\\n\";"}}. However, backslashes that are not inside string
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or character constants are not duplicated: @samp{\n} by itself
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stringifies to @t{"\n"}.
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stringizes to @t{"\n"}.
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All leading and trailing whitespace in text being stringified is
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All leading and trailing whitespace in text being stringized is
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ignored. Any sequence of whitespace in the middle of the text is
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converted to a single space in the stringified result. Comments are
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replaced by whitespace long before stringification happens, so they
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never appear in stringified text.
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converted to a single space in the stringized result. Comments are
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replaced by whitespace long before stringizing happens, so they
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never appear in stringized text.
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There is no way to convert a macro argument into a character constant.
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If you want to stringify the result of expansion of a macro argument,
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If you want to stringize the result of expansion of a macro argument,
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you have to use two levels of macros.
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@smallexample
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@ -1530,7 +1530,7 @@ xstr (foo)
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@expansion{} "4"
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@end smallexample
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@code{s} is stringified when it is used in @code{str}, so it is not
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@code{s} is stringized when it is used in @code{str}, so it is not
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macro-expanded first. But @code{s} is an ordinary argument to
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@code{xstr}, so it is completely macro-expanded before @code{xstr}
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itself is expanded (@pxref{Argument Prescan}). Therefore, by the time
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@ -1569,7 +1569,7 @@ but you could just as well write them as one token in the first place.
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Token pasting is most useful when one or both of the tokens comes from a
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macro argument. If either of the tokens next to an @samp{##} is a
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parameter name, it is replaced by its actual argument before @samp{##}
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executes. As with stringification, the actual argument is not
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executes. As with stringizing, the actual argument is not
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macro-expanded first. If the argument is empty, that @samp{##} has no
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effect.
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@ -1607,7 +1607,7 @@ struct command commands[] =
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It would be cleaner not to have to give each command name twice, once in
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the string constant and once in the function name. A macro which takes the
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name of a command as an argument can make this unnecessary. The string
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constant can be created with stringification, and the function name by
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constant can be created with stringizing, and the function name by
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concatenating the argument with @samp{_command}. Here is how it is done:
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@smallexample
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@ -1649,7 +1649,7 @@ eprintf ("%s:%d: ", input_file, lineno)
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The variable argument is completely macro-expanded before it is inserted
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into the macro expansion, just like an ordinary argument. You may use
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the @samp{#} and @samp{##} operators to stringify the variable argument
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the @samp{#} and @samp{##} operators to stringize the variable argument
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or to paste its leading or trailing token with another token. (But see
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below for an important special case for @samp{##}.)
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@ -2912,7 +2912,7 @@ macro, but not when it indirectly appears in its own definition.
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@cindex prescan of macro arguments
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Macro arguments are completely macro-expanded before they are
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substituted into a macro body, unless they are stringified or pasted
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substituted into a macro body, unless they are stringized or pasted
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with other tokens. After substitution, the entire macro body, including
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the substituted arguments, is scanned again for macros to be expanded.
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The result is that the arguments are scanned @emph{twice} to expand
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@ -2952,12 +2952,12 @@ appear during the main scan as an indirect self-reference and would not
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be expanded.
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@item
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Macros that call other macros that stringify or concatenate.
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Macros that call other macros that stringize or concatenate.
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If an argument is stringified or concatenated, the prescan does not
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occur. If you @emph{want} to expand a macro, then stringify or
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If an argument is stringized or concatenated, the prescan does not
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occur. If you @emph{want} to expand a macro, then stringize or
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concatenate its expansion, you can do that by causing one macro to call
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another macro that does the stringification or concatenation. For
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another macro that does the stringizing or concatenation. For
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instance, if you have
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@smallexample
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@ -3830,7 +3830,7 @@ implementation removes comments even before saving the macro
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replacement text, but it careful to do it in such a way that the
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observed effect is identical even in the function-like macro case.)
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The ISO stringification operator @samp{#} and token paste operator
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The ISO stringizing operator @samp{#} and token paste operator
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@samp{##} have no special meaning. As explained later, an effect
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similar to these operators can be obtained in a different way. Macro
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names that are embedded in quotes, either from the main file or after
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@ -203,7 +203,7 @@ error about an unterminated macro argument list.
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The C standard also specifies that a new line in the middle of the
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arguments to a macro is treated as whitespace. This white space is
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important in case the macro argument is stringified. The state variable
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important in case the macro argument is stringized. The state variable
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@code{parsing_args} is nonzero when the preprocessor is collecting the
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arguments to a macro call. It is set to 1 when looking for the opening
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parenthesis to a function-like macro, and 2 when collecting the actual
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@ -374,7 +374,7 @@ the pointers to the tokens of its expansion that are returned will always
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remain valid. However, macros are a little trickier than that, since
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they give rise to three sources of fresh tokens. They are the built-in
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macros like @code{__LINE__}, and the @samp{#} and @samp{##} operators
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for stringification and token pasting. I handled this by allocating
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for stringizing and token pasting. I handled this by allocating
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space for these tokens from the lexer's token run chain. This means
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they automatically receive the same lifetime guarantees as lexed tokens,
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and we don't need to concern ourselves with freeing them.
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@ -478,7 +478,7 @@ ways.
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I strongly recommend you have a good grasp of how the C and C++
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standards require macros to be expanded before diving into this
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section, let alone the code!. If you don't have a clear mental
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picture of how things like nested macro expansion, stringification and
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picture of how things like nested macro expansion, stringizing and
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token pasting are supposed to work, damage to your sanity can quickly
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result.
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@ -744,7 +744,7 @@ We would then have it take its spacing from the first of these, which
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carries source token @samp{foo} with no leading space.
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It is vital that cpplib get spacing correct in these examples since any
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of these macro expansions could be stringified, where spacing matters.
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of these macro expansions could be stringized, where spacing matters.
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So, this demonstrates that not just entering macro and argument
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expansions, but leaving them requires special handling too. I made
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