Documentation
¶
Overview ¶
Package ebnf contains the AST and parser for parsing the form of EBNF produced by Participle.
The self-referential EBNF is:
EBNF = Production* .
Production = <ident> "=" Expression "." .
Expression = Sequence ("|" Sequence)* .
SubExpression = "(" ("?!" | "?=")? Expression ")" .
Sequence = Term+ .
Term = "~"? (<ident> | <string> | ("<" <ident> ">") | SubExpression) ("*" | "+" | "?" | "!")? .
Index ¶
Constants ¶
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Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Expression ¶
type Expression struct {
Alternatives []*Sequence `@@ ( "|" @@ )*`
}
Expression is a set of alternatives separated by "|" in the EBNF.
func (*Expression) String ¶
func (e *Expression) String() (out string)
type LookaheadAssertion ¶
type LookaheadAssertion rune
LookaheadAssertion enum.
const ( LookaheadAssertionNone LookaheadAssertion = 0 LookaheadAssertionNegative LookaheadAssertion = '!' LookaheadAssertionPositive LookaheadAssertion = '=' )
Lookahead assertion enums.
func (*LookaheadAssertion) Capture ¶
func (l *LookaheadAssertion) Capture(tokens []string) error
type Node ¶
type Node interface {
// contains filtered or unexported methods
}
A Node in the EBNF grammar.
type Production ¶
type Production struct {
Production string `@Ident "="`
Expression *Expression `@@ "."`
}
Production of the grammar.
type SubExpression ¶
type SubExpression struct {
Lookahead LookaheadAssertion `"(" ("?" @("!" | "="))?`
Expr *Expression `@@ ")"`
}
SubExpression is an expression inside parentheses ( ... )
func (*SubExpression) String ¶
func (s *SubExpression) String() string
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