C# grammar for tree-sitter

Based on an export of the Roslyn grammar export with various changes in order to:

• Deal with differences between the parsing technologies
• Work around some bugs in that grammar
• Handle #if, #else, #elif, #endif blocks
• Support syntax highlighting/parsing of fragments
• Simplify the output tree

Comprehensive support for C# exists with the following exceptions:

• Non-ASCII identifiers
• Contextual keywords
• Global statements

• Tuples
• Discards
• Basic pattern matching
• Recursive pattern matching
• Ref locals and return
• Local function statements
• Expression bodied constructors
• Expression bodied destructors/finalizers
• Throw expressions
• Binary and _ literal support

• async main method
• Default literals (as default_expression)
• Inferred tuple element names
• Generic type pattern matching

• in parameter modifiers
• ref readonly method returns
• readonly struct
• ref struct
• Non-trailing named arguments
• _ leading binary and hex literals
• private protected modifier
• Conditional ref expressions

• stackalloc array initializers
• unmanaged generic type parameter constraint
• Attributes attached to auto property backing fields
• out support for parameters on initializers, constructors etc.

• readonly members
• Default interface methods
• switch expressions
• switch property patterns
• switch tuple patterns
• static local functions
• nullable reference types
• null-forgiving operator

• Official C# 6 Language Spec provides chapters that formally define the language grammar.
• Roslyn C# language grammar export
• SharpLab (web-based syntax tree playground based on Roslyn)