SYNTAX Directed Translation PPT || Compiler Construction
Download as PPTX, PDF0 likes155 views
The document discusses syntax-directed translation (SDT) which is a method of compiler implementation where source language translation is driven by the parser. SDT uses an augmented context-free grammar called an attribute grammar to control semantic analysis and translation. SDT translates a string into a sequence of actions by attaching actions to each rule of the grammar. The parsing process and parse trees are used to direct semantic analysis and translation of the source program according to the order specified by the semantic rules embedded in the grammar.
SYNTAX Directed Translation PPT || Compiler Construction
- 3. National College of Business Administration & Economics
- 4. Group Members Wamiq Ali Programmer Sarmad Shuja Programmer Zain Abid Programmer
- 5. Background Parser uses a CFG(Context-free-Grammar) to validate the input string and produce output for next phase of the compiler.
- 6. Introduction Syntax-directed translation (SDT) refers to a method of compiler implementation where the source language translation is completely driven by the parser. The parsing process and parse trees are used to direct semantic analysis and the translation of the source program. We can augment grammar with information to control the semantic analysis and translation. Such grammars are called attribute grammars.
- 7. Terminology A common method of syntax-directed translation is translating a string in to a sequence of actions by attaching one such action to each rule of a grammar. Formula Grammar + semantic rule = SDT (syntax directed translation)
- 8. Syntax Directed Translation Scheme 1 The Syntax directed translation scheme is a context -free grammar. 2 The syntax directed translation scheme is used to evaluate the order of semantic rules. 3 In translation scheme, the semantic rules are embedded within the right side of the productions. 4 The position at which an action is to be executed is shown by enclosed between braces. It is written within the right side of the production.
- 9. Implementation of Syntax directed Translation Syntax direct translation is implemented by constructing a parse tree and performing the actions in a left to right depth first order. SDT is implementing by parse the input and produce a parse tree as a result.
- 10. Top Down
- 11. Bottom Up
- 12. Limitation Without using global data to create side effects, some of the semantic actions cannot be performed. Example Checking whether a variable is defined before its usage. Checking the type and storage address of a variable. Checking whether a variable is used or not.
- 13. Common Approach A program with too many global variables is difficult to understand and maintain. Restrict the usage of global variables to essential items and use them as objects.
- 14. Thank You