• Grammar:
• Valid

EXPRESSION       <-  TERM (TERM_OPERATOR TERM)*
TERM             <-  FACTOR (FACTOR_OPERATOR FACTOR)*
FACTOR           <-  NUMBER / '(' EXPRESSION ')'
TERM_OPERATOR    <-  [-+]
FACTOR_OPERATOR  <-  [/*]
NUMBER           <-  [0-9]+
%whitespace      <-  [ \t\r\n]*

• Code:
• Valid

2 * (3 + 4)