Open-Source Fortran to Pascal Converter — Accurate Syntax Mapping

Fast Fortran-to-Pascal Converter: Migrate Legacy Code Quickly

What it does

Converts Fortran source code (common Fortran 77 / Fortran 90 constructs) into Pascal equivalents to help migrate legacy scientific or engineering codebases to modern Pascal environments (Free Pascal / Delphi).

Key features

• Automatic syntax translation: Converts common Fortran statements (PROGRAM, SUBROUTINE, FUNCTION, COMMON, DATA, DO loops, IF/ELSE) to Pascal syntax.
• Type mapping: Maps Fortran numeric types (INTEGER, REAL, DOUBLE PRECISION, COMPLEX) and LOGICAL to Pascal types; provides options for precision handling.
• Array handling: Translates fixed-dimension and assumed-size arrays; converts 1-based Fortran indexing to Pascal conventions while preserving semantics.
• I/O conversion: Converts simple READ/WRITE and formatted I/O into Pascal file and console I/O constructs.
• Modularization: Suggests Pascal unit separation for Fortran COMMON blocks and subprograms.
• Batch processing: Process multiple files and entire projects in one run.
• Diagnostics and reports: Lists unresolved constructs, incompatible extensions, and lines needing manual review.
• Configurable rules: Allow custom type mappings, naming conventions, and handling of platform-specific calls.
• Export targets: Emit Free Pascal-compatible code or Delphi-style units.

Typical limitations (what needs manual work)

• Complex preprocessor macros or nonstandard compiler extensions.
• Dynamic memory patterns using Fortran-specific allocators (especially pre-F90 code).
• Intricate formatted I/O with complex FORMAT statements.
• Low-level system or assembly interfacing.
• Precision-sensitive numerical idioms requiring algorithmic review after translation.

Recommended workflow

1. Run converter on a copy of the Fortran project with batch mode.
2. Review diagnostic report and fix flagged areas.
3. Compile translated code with Free Pascal (fpc) or Delphi; resolve compiler errors.
4. Run test suite / validation cases and compare outputs against original Fortran results.
5. Manually refactor idiomatic areas for Pascal style and performance.

Who benefits

• Teams modernizing scientific/engineering applications.
• Developers maintaining legacy code who prefer Pascal tooling.
• Organizations needing readable, maintainable translated code rather than rewrites.

If you want, I can:

• Generate a short checklist for validating translated programs, or
• Provide sample translations of a small Fortran routine to Pascal. Which would you prefer?