Semantic Analysis

• Abstract syntax tree; nodes
• Symbols and types
• Symbol table
• Varible and function declarations
• Type checking

Type Checking Example: Compact

The package provided here contains the Compact compiler.

This version has been improved to perform type checking in the C generator visitor. This visitor uses a second visitor to check types before deciding on which code to generate. The checks are related with the use of boolean expressions in tests (while, if, and if-else nodes) and with type consistency in operators (in this case, although we could have decided otherwise, operators such as + and - must have arguments of the same type and this type must be integer). In addition, the compiler now checks if a variable has the proper type in certain cases (for instance, in the tests mentioned above).

Simple Type Checking Example

The following example considers a simple grammar and performs the whole of the semantic analysis process and, finally, generates the corresponding C code. The semantic analysis process must account for variables (they must be declared before they can be used) and for their types (all types must be used correctly).

• Simple Semantic Analysis Example (and C generation)