Project 2 - For Statement

[Mend25]

Grupo

• Victor Mendonça Aguiar
• Ian Medeiros Melo
• Guilherme Montenegro de Albuquerque
• João Victor Fellows Rabêlo
• Rafael Alves de Azevedo

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Summary

Introduce full syntactic support for C-style for loops in the MiniC language, including AST integration, parser support for optional header clauses, keyword reservation, and supporting documentation/specification.

This PR implements the for construct at the parsing level, adding end-to-end syntactic support in MiniC through a new Statement::For AST variant and parser logic capable of handling optional initialization, condition, and update clauses. It also reserves for as a language keyword to prevent identifier conflicts.

Type checking and interpretation for for loops are intentionally left unimplemented at this stage, with explicit errors added to make that limitation clear until Milestone 2. In addition, the PR includes detailed design documentation, requirements, scenarios, and task breakdowns, while remaining fully backward compatible with the existing language.

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Changes Made

AST (ast.rs)

• Add the Statement::For { init, cond, update, body } variant
• Represent the for loop with:
  • an optional initialization clause
  • an optional condition clause
  • an optional update clause
  • a mandatory block body

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Parser (statements.rs)

• Add parsing support for C-style for statements

• Supported syntax:

  • for (init; cond; update) block

• Header clause rules:

  • init is optional
  • cond is optional
  • update is optional

• Add helper parsers for:

  • declarations without trailing semicolons
  • assignments without trailing semicolons

• Update statement dispatch order so for_statement is parsed before declaration and assignment

• Update grammar documentation and parser comments to reflect the new syntax

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Language Rules

• Reserve for as a keyword
• Prevent for from being used as an identifier
• Keep the change backward compatible with existing programs

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Specification, Design & Planning

• Add detailed openspec documentation covering:
  • design rationale
  • requirements
  • supported scenarios
  • parsing expectations
  • AST expectations
  • implementation planning and task breakdown

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Tooling / Infra

• Refactor flake.nix to simplify the dev shell definition
• No functional changes to the build or development environment