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/* scanner for a toy JavaScript-like language */
%{
/* need this for the call to atof() below */
#include <math.h>
%}
DIGIT [0-9]
ID [a-z_$][a-z0-9_$]*
STRQ '([^\']|(\\\'))*'
STRDQ "([^\"]|(\\\"))*"
%%
{DIGIT}+ {
printf( "An integer: %s (%d)\n", yytext,
atoi( yytext ) );
}
{DIGIT}+"."{DIGIT}* {
printf( "A float: %s (%g)\n", yytext,
atof( yytext ) );
}
if|else|for|while|do|break|switch|case|function|return|new|delete|try|throw|catch|class|public|private {
printf( "A keyword: %s\n", yytext );
}
{ID} printf( "An identifier: %s\n", yytext );
{STRQ}|{STRDQ} printf( "A string: %s\n", yytext );
"."|"+"|"-"|"*"|"/"|"="|"!"|">"|"<"|"!=="|"==="|">="|"<="|"++"|"--"|"=>" printf( "An operator: %s\n", yytext );
";" printf( "A semicolumn\n" );
"(" printf( "A left parenthesis\n" );
")" printf( "A right parenthesis\n" );
"{" printf( "A left bracket\n" );
"}" printf( "A right bracket\n" );
":" printf( "A colon\n" );
"?" printf( "A question mark\n" );
[ \t\n]+ /* eat up whitespace */
. printf( "Unrecognized character: %s\n", yytext );
%%
int yywrap()
{
return 1;
}
int main(int argc, const char* argv[])
{
++argv, --argc; /* skip over program name */
if ( argc > 0 )
yyin = fopen( argv[0], "r" );
else
yyin = stdin;
/* YY_BUFFER_STATE hello = yy_scan_string("(x)=>{ return x !== 1; }"); */
/* yypush_buffer_state(hello); */
yylex();
/* yy_delete_buffer(hello); */
return 0;
}
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