Associativity of Operators

If operand has operators on both side then by connection, operand should be associated with the operator on the left.

In most programming languages arithmetic operators like addition, subtraction, multiplication, and division are left associative.

• Token string: 9 - 5 + 2
• Production rules
  list   → list - digit | digit
  digit → 0 | 1 | 2 | . . . | 9
• Parse tree for left-associative operator is

figure 24 on pg. 31

In the C programming language the assignment operator, =, is right associative. That is, token string a = b = c should be treated as a = (b = c).

• Token string: a = b =c.
• Production rules:
  right   →  letter = right | letter
  letter  →  a | b | . . . | z
• Parse tree for right-associative operator is:

Figure