pkg/analysis_server/doc/design/features/semantic_highlighting.md - sdk.git - Git at Google

 # Semantic highlighting

     LSP:    [textDocument/semanticTokens/*][] requests
     Legacy: `analysis.highlights` notification

 Semantic highlighting makes it easier for the user to understand the code by
 making certain syntactic and semantic aspects of the code more visible. The
 client typically uses this information to apply text color or other highlighting
 to the code being shown in the editor.

 The design of the feature is largely dictated by the protocol, but there are
 some areas where we have some flexibility. This document will cover those areas.

 ## Syntactic highlighting

 Syntactic highlighting covers highlighting that is based purely on the syntax of
 the language. For example, the highlighting of string literals or comments is
 part of syntactic highlighting.

 ### Handling keywords

 There is one question related to syntactic highlighting: the handling of
 keywords. Dart has three categories of identifiers with special semantics, and
 we needed to decide whether to explicitly represent these three categories of
 identifiers or whether to ignore the distinctions. It could be argued that
 ignoring the distinction would violate the principle of [language fidelity][].
 It could also be argued that making the distinction might be confusing for the
 user.

 In the end, we decided that the better interpretation of the language spec is
 that there are two important categories: identifiers that are functioning as a
 keyword and identifiers that are not. As a result, we treat all of these as
 keywords whenever they serve the function of a keyword, and treat them as
 identifiers when they don't.

 ## Semantic highlighting

 Semantic highlighting covers highlighting that is dependent on knowing the
 semantics of the code. For example, highlighting static members of a class
 differently than instance members requires knowing which member is being
 referenced and whether it's a static member.

 [language fidelity]: ../design/principles/language_fidelity.md
 [textDocument/semanticTokens/*]: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_semanticTokens
	# Semantic highlighting

	LSP: [textDocument/semanticTokens/*][] requests
	Legacy: `analysis.highlights` notification

	Semantic highlighting makes it easier for the user to understand the code by
	making certain syntactic and semantic aspects of the code more visible. The
	client typically uses this information to apply text color or other highlighting
	to the code being shown in the editor.

	The design of the feature is largely dictated by the protocol, but there are
	some areas where we have some flexibility. This document will cover those areas.

	## Syntactic highlighting

	Syntactic highlighting covers highlighting that is based purely on the syntax of
	the language. For example, the highlighting of string literals or comments is
	part of syntactic highlighting.

	### Handling keywords

	There is one question related to syntactic highlighting: the handling of
	keywords. Dart has three categories of identifiers with special semantics, and
	we needed to decide whether to explicitly represent these three categories of
	identifiers or whether to ignore the distinctions. It could be argued that
	ignoring the distinction would violate the principle of [language fidelity][].
	It could also be argued that making the distinction might be confusing for the
	user.

	In the end, we decided that the better interpretation of the language spec is
	that there are two important categories: identifiers that are functioning as a
	keyword and identifiers that are not. As a result, we treat all of these as
	keywords whenever they serve the function of a keyword, and treat them as
	identifiers when they don't.

	## Semantic highlighting

	Semantic highlighting covers highlighting that is dependent on knowing the
	semantics of the code. For example, highlighting static members of a class
	differently than instance members requires knowing which member is being
	referenced and whether it's a static member.

	[language fidelity]: ../design/principles/language_fidelity.md
	[textDocument/semanticTokens/*]: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_semanticTokens