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Refactor YY_INPUT so it calls a new yyread() internal function....

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...rather than splicing a bunch of exposed guts into the middle of
yylex().  yyread() is put in the set of functions that gets
prefix-modified.

This means buffer refill can be documented without C-specific
references to YY_INPUT.

It should also enable actually having a non-macro replacement
for YY_INPUT, with a bit more work.
This commit is contained in:
Eric S. Raymond 2020-10-11 11:05:12 -04:00
parent 1094c2a137
commit 956ac03b7d
2 changed files with 93 additions and 84 deletions
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3
src/FlexLexer.h
View File

@ -139,6 +139,7 @@ public:
void yypush_buffer_state( yy_buffer_state* new_buffer );
void yypop_buffer_state();
virtual int yyread(char *buf, size_t);
virtual int yylex();
virtual void switch_streams( std::istream& new_in, std::ostream& new_out );
virtual void switch_streams( std::istream* new_in = 0, std::ostream* new_out = 0 );
@ -148,7 +149,7 @@ protected:
virtual int LexerInput( char* buf, int max_size );
virtual void LexerOutput( const char* buf, int size );
virtual void LexerError( const char* msg );
void yyunput( int c, char* buf_ptr );
int yyinput();

174
src/cpp-flex.skl
View File

@ -124,6 +124,7 @@ m4_ifelse(M4_MODE_PREFIX,yy,,
#define yyalloc M4_MODE_PREFIX[[alloc]]
#define yyrealloc M4_MODE_PREFIX[[realloc]]
#define yyfree M4_MODE_PREFIX[[free]]
#define yyread M4_MODE_PREFIX[[read]]
)
%endif
%endif
@ -1503,61 +1504,101 @@ m4_ifdef( [[M4_YY_NOT_IN_HEADER]],
m4_ifdef( [[M4_YY_NOT_IN_HEADER]],
[[
#ifndef YY_EXIT_FAILURE
#define YY_EXIT_FAILURE 2
#endif
%if-c-only
static void yynoreturn yy_fatal_error YYFARGS1(const char*, msg) {
M4_YY_DECL_GUTS_VAR();
M4_YY_NOOP_GUTS_VAR();
fprintf( stderr, "%s\n", msg );
exit( YY_EXIT_FAILURE );
}
%endif
%if-c++-only
void yyFlexLexer::LexerError( const char* msg ) {
M4_YY_DECL_GUTS_VAR();
std::cerr << msg << std::endl;
exit( YY_EXIT_FAILURE );
}
%endif
/* Report a fatal error. */
#ifndef YY_FATAL_ERROR
%if-c-only
#define YY_FATAL_ERROR(msg) yy_fatal_error( msg M4_YY_CALL_LAST_ARG)
%endif
%if-c++-only
#define YY_FATAL_ERROR(msg) LexerError( msg )
%endif
#endif
/* Legacy interface */
#ifndef YY_INPUT
#define YY_INPUT(buf,result,max_size) do {result = yyread(buf, max_size M4_YY_CALL_LAST_ARG);} while (0)
/* Gets input and stuffs it into "buf". number of characters read, or YY_NULL,
* is returned in "result".
*/
#ifndef YY_INPUT
#define YY_INPUT(buf,result,max_size) \
%if-c-only \
m4_ifdef( [[M4_MODE_CPP_USE_READ]], [[ \
errno=0; \
while ( (result = (int) read( fileno(yyin), buf, (yy_size_t) max_size )) < 0 ) \
{ \
if( errno != EINTR) \
{ \
YY_FATAL_ERROR( "input in flex scanner failed" ); \
break; \
} \
errno=0; \
clearerr(yyin); \
}\
]]) \
m4_ifdef( [[M4_MODE_NO_CPP_USE_READ]], [[ \
if ( YY_CURRENT_BUFFER_LVALUE->yy_is_interactive ) \
{ \
int c = '*'; \
int n; \
for ( n = 0; n < max_size && \
(c = getc( yyin )) != EOF && c != '\n'; ++n ) \
buf[n] = (char) c; \
if ( c == '\n' ) \
buf[n++] = (char) c; \
if ( c == EOF && ferror( yyin ) ) \
YY_FATAL_ERROR( "input in flex scanner failed" ); \
result = n; \
} \
else \
{ \
errno=0; \
while ( (result = (int) fread(buf, 1, (yy_size_t) max_size, yyin)) == 0 && ferror(yyin)) \
{ \
if( errno != EINTR) \
{ \
YY_FATAL_ERROR( "input in flex scanner failed" ); \
break; \
} \
errno=0; \
clearerr(yyin); \
} \
}\
]]) \
%endif \
\
%if-c++-only C++ definition \
if ( (int)(result = LexerInput( (char *) buf, max_size )) < 0 ) \
YY_FATAL_ERROR( "input in flex scanner failed" );
%if-c++-only
int yyFlexLexer::yyread(char *buf, size_t max_size) {
%endif
%if-c-only
static int yyread(char *buf, size_t max_size M4_YY_PROTO_LAST_ARG) {
%endif
int result;
M4_YY_DECL_GUTS_VAR();
%if-c-only
m4_ifdef( [[M4_MODE_CPP_USE_READ]], [[
errno=0;
while ( (result = (int) read( fileno(yyin), buf, (yy_size_t) max_size )) < 0 )
{
if( errno != EINTR)
{
YY_FATAL_ERROR( "input in flex scanner failed" );
break;
}
errno=0;
clearerr(yyin);
}
]])
m4_ifdef( [[M4_MODE_NO_CPP_USE_READ]], [[
if ( YY_CURRENT_BUFFER_LVALUE->yy_is_interactive )
{
int c = '*';
int n;
for ( n = 0; n < max_size &&
(c = getc( yyin )) != EOF && c != '\n'; ++n )
buf[n] = (char) c;
if ( c == '\n' )
buf[n++] = (char) c;
if ( c == EOF && ferror( yyin ) )
YY_FATAL_ERROR( "input in flex scanner failed" );
result = n;
}
else
{
errno=0;
while ( (result = (int) fread(buf, 1, (yy_size_t) max_size, yyin)) == 0 && ferror(yyin))
{
if( errno != EINTR)
{
YY_FATAL_ERROR( "input in flex scanner failed" );
break;
}
errno=0;
clearerr(yyin);
}
}
]])
%endif
%if-c++-only C++ definition
if ( (int)(result = LexerInput( (char *) buf, max_size )) < 0 )
YY_FATAL_ERROR( "input in flex scanner failed" );
%endif
return result;
}
#endif
]])
@ -1577,19 +1618,6 @@ m4_ifdef( [[M4_YY_NOT_IN_HEADER]],
#define YY_START_STACK_INCR 25
#endif
m4_ifdef( [[M4_YY_NOT_IN_HEADER]],
[[
/* Report a fatal error. */
#ifndef YY_FATAL_ERROR
%if-c-only
#define YY_FATAL_ERROR(msg) yy_fatal_error( msg M4_YY_CALL_LAST_ARG)
%endif
%if-c++-only
#define YY_FATAL_ERROR(msg) LexerError( msg )
%endif
#endif
]])
%if-tables-serialization structures and prototypes
m4preproc_include(`tables_shared.h')
@ -3338,26 +3366,6 @@ int yyFlexLexer::yy_top_state()
}
]])
#ifndef YY_EXIT_FAILURE
#define YY_EXIT_FAILURE 2
#endif
%if-c-only
static void yynoreturn yy_fatal_error YYFARGS1(const char*, msg) {
M4_YY_DECL_GUTS_VAR();
M4_YY_NOOP_GUTS_VAR();
fprintf( stderr, "%s\n", msg );
exit( YY_EXIT_FAILURE );
}
%endif
%if-c++-only
void yyFlexLexer::LexerError( const char* msg ) {
M4_YY_DECL_GUTS_VAR();
std::cerr << msg << std::endl;
exit( YY_EXIT_FAILURE );
}
%endif
/* Redefine yyless() so it works in section 3 code. */
#undef yyless