%{
   /* C definitions */
#define YY_SKIP_YYWRAP
int yywrap(void) { return 1; }
%}
   /* definitions */
%option always-interactive
delim   [ \t]
ws      {delim}+
letter  [A-Za-z]
digit   [0-9]
ident   {letter}({letter}|{digit})*
number  {digit}+(\.{digit}+)?(E[+\-]?{digit}+)?
%%
   /* rules */
{ws}        { putchar('_'); }
{number}    { printf("<b>"); ECHO; printf("</b>"); }
{ident}     { printf("<i>"); ECHO; printf("</i>"); }
"."         { ECHO; exit(1); }
.|\n        { ECHO; }
%%
   /* user code */
int main(void) {
  return yylex();
}