CrabPascal Adds Delphi-Style Conditional Compilation

Delphi projects aren’t just single-source files—they often rely on conditional compilation directives to adapt code across platforms. CrabPascal, a verification and execution tool for Pascal, now includes a Delphi-inspired preprocessor to handle these use cases.

An integrated preprocessor, not a compiler

Since version 1.5.2 (and refined in 2.x), CrabPascal offers an in-line preprocessor that evaluates directives like {$IFDEF}, {$DEFINE}, or {$INCLUDE} before the main code analysis. The goal? To replicate Delphi’s compilation behavior, where code blocks can be enabled or disabled based on defined symbols. For example, a Windows project might include uses Winapi.Windows; via {$IFDEF MSWINDOWS}, while a Linux version uses uses Posix.Unistd;.

CrabPascal doesn’t replace compilers like Free Pascal or Delphi. Instead, it focuses on managing preprocessor directives, with partial support for advanced features like numeric conditions ({$IF}) or editorial regions ({$REGION}). Exotic or compiler-specific directives (such as {$MESSAGE}) may be ignored or flagged as warnings.

Practical integration for developers

The preprocessor activates when loading .pas units and can be controlled via a TOML configuration in the project. Symbols can be defined directly in code or through configuration, simplifying the standardization of flags across environments (CI, development machines, etc.).

For teams migrating Delphi units to other platforms, CrabPascal provides a crab-pascal preproc command to inspect preprocessor output before compilation—a useful way to spot symbol inconsistencies or unexpected conditional inclusions.

In short, this feature strengthens compatibility with the Delphi ecosystem while remaining lightweight and targeted, without aiming to replace a full compiler.