Errors with the Flex Tool - lex

Question

/*Regular Definitions*/
delim[\t\n]
WS{delim}+
letter[A-Za-z]
digit[0-9]
id{letter}({letter|digit})*
number{digit}+(\.{digit}+?(E[+-]?{digit}+)?
%%
{WS}{/*do nothing*/}
if{printf("\nIF found");return 0;}
then{printf("\nTHEN found");return 0;}
else{printf("\nELSE found");return 0;}
{id}{printf("\nID found");return 0;}
{number}{printf("\nNUMBER found");return 0;}
"<"{printf("\nLess than symbol found.");return 0;}
"<="{printf("\nLess than or Equals to symbol found.");return 0;}
"="{printf("\nEquals to symbol found.");return 0;}
"<>"{printf("\nNot equals to symbol found.");return 0;}
">"{printf("\nGreater than symbol found.");return 0;}
">="{printf("\nGreater than or equal to symbol found.");return 0;}
%%
While using flex to compile this
G:\>flex Lex.l
I get the following errors:
"Lex.l", line 14: unrecognized rule
"Lex.l", line 14: unrecognized rule
"Lex.l", line 14: unrecognized rule
"Lex.l", line 14: unrecognized rule
"Lex.l", line 14: unrecognized rule
"Lex.l", line 27: EOF encountered inside an action
Can anyone help me with it ?
Thanks.

Answer 1

1.- Surround with brackets each expression of the alternation.
{letter}|{digit}
2.- A closing parentheses was missed in the number definition. I added it before first ?, but not sure.
number{digit}+(\.{digit}+)?(E[+-]?{digit}+)?
3.- In the rule section, separate with spaces the pattern and the C code.
{WS} {/*do nothing*/}
This should work, or at least compile:
/*Regular Definitions*/
delim[\t\n]
WS{delim}+
letter[A-Za-z]
digit[0-9]
id{letter}({letter}|{digit})*
number{digit}+(\.{digit}+?(E[+-]?{digit}+)?)
%%
{WS} {/*do nothing*/}
if {printf("\nIF found");return 0;}
then {printf("\nTHEN found");return 0;}
else {printf("\nELSE found");return 0;}
{id} {printf("\nID found");return 0;}
{number} {printf("\nNUMBER found");return 0;}
"<" {printf("\nLess than symbol found.");return 0;}
"<=" {printf("\nLess than or Equals to symbol found.");return 0;}
"=" {printf("\nEquals to symbol found.");return 0;}
"<>" {printf("\nNot equals to symbol found.");return 0;}
">" {printf("\nGreater than symbol found.");return 0;}
">=" {printf("\nGreater than or equal to symbol found.");return 0;}
%%