Syntax-directed translation formulas

Syntax-directed translation. 3 formulas for GATE CS Compiler Design, each with when to use it. Each is explained in the topic notes.

All 3 Syntax-directed translation formulas

FORM OF A SYNTHESIZED RULE

A . s = f (X_{1} . a_{1}, \dots, X_{n} . a_{n}) for the production A \to X_{1} X_{2} \dots X_{n}

The attribute being defined belongs to the head $A$ ; its arguments are attributes of the body symbols (or of $A$ itself).

FORM OF AN INHERITED RULE

X_{i} . a = g (A . b, X_{1} . c_{1}, \dots, X_{n} . c_{n}) for the production A \to X_{1} X_{2} \dots X_{n}

The attribute being defined belongs to a body symbol $X_{i}$ ; the arguments may be attributes of the head and of the body symbols.

L-ATTRIBUTED CONDITION

X_{i} . inh = g (A . inh, X_{1} . any, \dots, X_{i - 1} . any), no dependence on X_{i + 1}, \dots, X_{n} or on A . syn

Also allowed: dependence on other attributes of $X_{i}$ itself, provided that creates no cycle. Not allowed: dependence on a synthesized attribute of the head $A$ . Synthesized attributes of $A$ may use any attribute in the production, including $A$ 's inherited attributes, provided no cycle results.

Where this was asked: 2020 (1), 2022 (1), 2023 (1), 2024 (2), 2025 (1), 2026 (1). See the 7 previous-year questions on Syntax-directed translation. This shows what was asked, not what will be asked.

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Syntax-directed translation: the notes and 7 solved previous-year questions