Motivation

Issue #40 highlighted the absence of support for unary operations in our compiler. Unary operations, such as ! (logical NOT) and - (negation), are fundamental to many programming constructs and must be properly handled to ensure the compiler's correctness and completeness.

This PR addresses the parser-side implementation of unary operations, ensuring they are correctly parsed and integrated into the AST with the appropriate precedence.

Changes

1. ANTLR Grammar:

   • Added support for unary operations (! and -) with higher precedence than binary operations.
   • Updated the grammar to ensure unary operations are parsed before binary operations, adhering to standard operator precedence rules.

2. AST:

   • Introduced a new UnaryOp case class to represent unary operations in the AST:

     case class UnaryOp(op: String, expr: Expression) extends Expression

   • This allows the AST to accurately capture unary operations like !flag or -value.

3. ASTBuilder:

   • Extended the visitExpression method to handle unary operations during the AST construction process.
   • Ensured that unary operations are correctly parsed and transformed into UnaryOp nodes in the AST.

Testing

To validate the changes, a comprehensive test file has been added (currently commented out) that includes examples of all supported unary and binary operations. The test cases cover:

• Logical NOT (!)
• Negation (-)
• Combinations of unary and binary operations (e.g., -12 + 4, !flag && isValid)

Once the implementation is finalized, the test file will be uncommented