grammar

Documentation

Overview

Package grammar extracts lexical vocabulary from the grammars of the parsers gomplate actually runs, so the editor tokenizers stay in step with them instead of being transcribed by hand.

Index

• func CELGrammarSource() string
• func TranslateRuleBody(body string, rules map[string]string) (string, error)
• type CELGrammar
  • func ParseCEL() (*CELGrammar, error)
• type GoTemplateGrammar
  • func ParseGoTemplate() (*GoTemplateGrammar, error)

Functions

func CELGrammarSource

func CELGrammarSource() string

CELGrammarSource returns the vendored grammar text.

func TranslateRuleBody

func TranslateRuleBody(body string, rules map[string]string) (string, error)

TranslateRuleBody converts one ANTLR lexer rule body into JS regex source, inlining any referenced rule from rules (transitively).

Types

type CELGrammar

type CELGrammar struct {
	// Operators are the punctuation tokens, ordered longest-first so a
	// tokenizer trying them in sequence never lets `<` shadow `<=`.
	Operators []string
	// Keywords are the literal word tokens: in, true, false, null.
	Keywords []string
	// Patterns maps a composite token rule (STRING, NUM_INT, IDENTIFIER, ...)
	// to JS regex source.
	Patterns map[string]string
}

CELGrammar is the lexical vocabulary of CEL, extracted from CEL.g4.

func ParseCEL

func ParseCEL() (*CELGrammar, error)

ParseCEL extracts the lexical vocabulary from the vendored CEL.g4.

type GoTemplateGrammar

type GoTemplateGrammar struct {
	// Keywords are the action keywords: if, range, end, ...
	Keywords []string
	// Builtins are the functions text/template supplies itself.
	Builtins []string
	// LeftDelim and RightDelim open and close an action.
	LeftDelim, RightDelim string
	// LeftComment and RightComment open and close a comment inside an action.
	LeftComment, RightComment string
	// TrimMarker abuts a delimiter to trim adjacent whitespace.
	TrimMarker string
}

GoTemplateGrammar is the lexical vocabulary of Go's text/template, read out of the standard library's own lexer and function table. All three are unexported there, so they are recovered from the AST -- the same approach gencel already uses to read gomplate's own sources.

func ParseGoTemplate

func ParseGoTemplate() (*GoTemplateGrammar, error)

ParseGoTemplate recovers the text/template vocabulary from the standard library sources of the toolchain building this package.