tree-sitter-c-sharp

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

Status

Comprehensive support for C# exists with the following exceptions:

• async and await cannot be used as identifiers

C# 7.0 features (complete)

• 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

C# 7.1 (complete)

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

C# 7.2 (complete)

• 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

C# 7.3 (complete)

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

C# 8.0 (complete)

• readonly members
• Default interface methods
• switch expressions
• switch property patterns
• switch tuple patterns
• static local functions
• Nullable reference types
• Null-forgiving operator
• Null-coalescing assignment

C# 9.0 (complete)

• Covariant returns
• Extending partial methods
• Extension GetEnumerator
• Function pointers
• Init properties
• Lambda discard parameters
• Local function attributes
• Module initializers
• Native integers
• Patterns
  • Simple type patterns
  • Relational patterns
  • Logical patterns
• Records
• Skip Locals Init
• Static anonymous functions
• Target-typed conditional expression
• Target-typed new
• Top-level statements

References

• 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)