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/*
* @LANG: c++
*/
#include <iostream>
#include <string.h>
using namespace std;
#define TK_Dlit 192
#define TK_Slit 193
#define TK_Float 194
#define TK_Id 195
#define TK_NameSep 197
#define TK_Arrow 211
#define TK_PlusPlus 212
#define TK_MinusMinus 213
#define TK_ArrowStar 214
#define TK_DotStar 215
#define TK_ShiftLeft 216
#define TK_ShiftRight 217
#define TK_IntegerDecimal 218
#define TK_IntegerOctal 219
#define TK_IntegerHex 220
#define TK_EqualsEquals 223
#define TK_NotEquals 224
#define TK_AndAnd 225
#define TK_OrOr 226
#define TK_MultAssign 227
#define TK_DivAssign 228
#define TK_PercentAssign 229
#define TK_PlusAssign 230
#define TK_MinusAssign 231
#define TK_AmpAssign 232
#define TK_CaretAssign 233
#define TK_BarAssign 234
#define TK_DotDotDot 240
#define TK_Whitespace 241
#define TK_Comment 242
struct Scanner
{
int cs, act;
char *tokstart, *tokend;
bool isCxx;
void token( int tok );
void run( char *buf );
};
%%{
machine Scanner;
# Process all comments, relies on isCxx being set.
comment := |*
'*/' {
if ( ! isCxx )
fgoto main;
else {
cout << "comm char: " << tokstart[0] << endl;
cout << "comm char: " << tokstart[1] << endl;
}
};
'\n' {
if ( isCxx )
fgoto main;
else
cout << "comm char: " << tokstart[0] << endl;
};
any {
cout << "comm char: " << tokstart[0] << endl;
};
*|;
main := |*
# Single and double literals.
( 'L'? "'" ( [^'\\\n] | /\\./ )* "'" ) { token( TK_Slit );};
( 'L'? '"' ( [^"\\\n] | /\\./ )* '"' ) { token( TK_Dlit );};
# Identifiers
( [a-zA-Z_] [a-zA-Z0-9_]* ) { token( TK_Id ); };
# Floating literals.
fract_const = digit* '.' digit+ | digit+ '.';
exponent = [eE] [+\-]? digit+;
float_suffix = [flFL];
( fract_const exponent? float_suffix? |
digit+ exponent float_suffix? ) { token( TK_Float );};
# Integer decimal. Leading part buffered by float.
( ( '0' | [1-9] [0-9]* ) [ulUL]{0,3} ) { token( TK_IntegerDecimal );};
# Integer octal. Leading part buffered by float.
( '0' [0-9]+ [ulUL]{0,2} ) { token( TK_IntegerOctal );};
# Integer hex. Leading 0 buffered by float.
( '0' ( 'x' [0-9a-fA-F]+ [ulUL]{0,2} ) ) { token( TK_IntegerHex );};
# Only buffer the second item, first buffered by symbol. */
'::' {token( TK_NameSep );};
'==' {token( TK_EqualsEquals );};
'!=' {token( TK_NotEquals );};
'&&' {token( TK_AndAnd );};
'||' {token( TK_OrOr );};
'*=' {token( TK_MultAssign );};
'/=' {token( TK_DivAssign );};
'%=' {token( TK_PercentAssign );};
'+=' {token( TK_PlusAssign );};
'-=' {token( TK_MinusAssign );};
'&=' {token( TK_AmpAssign );};
'^=' {token( TK_CaretAssign );};
'|=' {token( TK_BarAssign );};
'++' {token( TK_PlusPlus );};
'--' {token( TK_MinusMinus );};
'->' {token( TK_Arrow );};
'->*' {token( TK_ArrowStar );};
'.*' {token( TK_DotStar );};
# Three char compounds, first item already buffered. */
'...' { token( TK_DotDotDot );};
# Single char symbols.
( punct - [_"'] ) { token( tokstart[0] );};
# Comments and whitespace. Handle these outside of the machine so that se
# don't end up buffering the comments.
'/*' { isCxx = false; fgoto comment; };
'//' { isCxx = true; fgoto comment; };
( any - 33..126 )+ { token( TK_Whitespace );};
*|;
}%%
%% write data nofinal;
void Scanner::token( int tok )
{
const char *data = tokstart;
int len = tokend - tokstart;
cout << "<" << tok << "> ";
if ( data != 0 ) {
for ( int i = 0; i < len; i++ )
cout << data[i];
}
cout << '\n';
}
void Scanner::run( char *buf )
{
int len = strlen( buf );
%% write init;
char *p = buf;
char *pe = buf + len;
%% write exec;
if ( cs == Scanner_error ) {
/* Machine failed before finding a token. */
cout << "PARSE ERROR" << endl;
}
%% write eof;
}
int main()
{
Scanner scanner;
scanner.run(
"//hello*/\n"
"/*hi there*/ hello 0x88\n"
);
return 0;
}
#ifdef _____OUTPUT_____
comm char: h
comm char: e
comm char: l
comm char: l
comm char: o
comm char: *
comm char: /
comm char: h
comm char: i
comm char:
comm char: t
comm char: h
comm char: e
comm char: r
comm char: e
<241>
<195> hello
<241>
<220> 0x88
#endif
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