Document predefined compiler symbols in F# compiler directives #49386
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Co-authored-by: BillWagner <[email protected]>
Co-authored-by: BillWagner <[email protected]>
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[WIP] Include documentation for all predefined symbols
Document predefined compiler symbols in F# compiler directives
Oct 21, 2025
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BillWagner
October 21, 2025 13:59
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Pull Request Overview
This PR adds comprehensive documentation for predefined compiler symbols in F# compiler directives, addressing a documentation gap where users were unclear about automatically defined symbols like DEBUG.
Key Changes:
- Added a new "Predefined symbols" section documenting build configuration symbols (
DEBUG,TRACE), compilation mode symbols (COMPILED,INTERACTIVE), and target framework symbols - Included practical code examples showing how to use these symbols in conditional compilation
- Added cross-references to related documentation (Assertions, F# Interactive, compiler options)
BillWagner
approved these changes
Oct 22, 2025
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Fixes #[issue_number]
This PR addresses the missing documentation for predefined compiler symbols that the F# compiler and build system automatically define. Users were unclear about which symbols (like
DEBUG) are automatically available for conditional compilation.Changes
Added a comprehensive "Predefined symbols" section to the F# compiler directives documentation that covers:
Build configuration symbols
DEBUG: Automatically defined in Debug builds, used with assertions and diagnostic codeTRACE: Defined for builds with tracing enabledCompilation mode symbols
COMPILED: Defined when compiling with the F# compilerINTERACTIVE: Defined when running in F# Interactive (dotnet fsi)Target framework symbols
NET6_0_OR_GREATER,NETSTANDARD2_0, etc.) via the existingpreprocessor-symbols.mdinclude fileThe documentation includes practical examples and cross-references to related topics (Assertions, F# Interactive, and compiler options). This brings the F# documentation in line with the C# preprocessor directives documentation structure.
Related
Original prompt
Fixes #45478
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