Syntax-Directed Definitions and Translation Schemes When we associate semantic rules with productions,we use two notations: Syntax-Directed Definitions Translation Schemes 。 Syntax-Directed Definitions: give high-level specifications for translations hide many implementation details such as order of evaluation of semantic actions. We associate a production rule with a set of semantic actions,and we do not say when they will be evaluated. Translation Schemes: indicate the order of evaluation of semantic actions associated with a production rule. In other words,translation schemes give a little bit information about implementation details. CS308 Compiler Theory 3Syntax-Directed Definitions and Translation Schemes • When we associate semantic rules with productions, we use two notat ions: – Syntax-Directed Definitions – Translation Schemes • Syntax-Directed Definitions: – give high-level specifications for translations – hide many implementation details such as order of evaluation of semantic actions. – We associate a p yy roduction rule with a set of semantic actions, and we do not sa y when the y will be evaluated. • Translation Schemes: – i di h d f l i f i i i d i h d i l indicate t he or der o f evaluation o f semantic actions associate d wit h a pro duction rule. – In other words, translation schemes give a little bit information about implementation details. CS308 Compiler Theory 3