Syntax-Directed Translation

Specifying the translation of a source language construct in terms of attributes of its syntactic components. The basic idea is use the productions to specify a (typically recursive) procedure for translation. For example, consider the production

    stmt-list → stmt-list ; stmt
  

To process the left stmt-list, we

1. Call ourselves recursively to process the right stmt-list (which is smaller). This will, say, generate code for all the statements in the right stmt-list.
2. Call the procedure for stmt, generating code for stmt.
3. Process the left stmt-list by combining the results for the first two steps as well as what is needed for the semicolon (a terminal so we do not further delegate its actions). In this case we probably concatenate the code for the right stmt-list and stmt.

To avoid having to say the right stmt-listwe write the production as

    stmt-list → stmt-list1 ; stmt
  

where the subscript is used to distinguish the two instances of stmt-list.