optional* ( parser -- parser )

Vocabulary
peg

Inputs

parser

Outputs

parser

Word description
Returns a parser that parses 0 or 1 instances of the parser. The AST produced is f if 0 instances are parsed, otherwise it is a singleton array containing the AST produced by parser or an empty array if the AST produced was ignore.

See also
optional

Definition

USING: kernel peg.private ;

IN: peg

: optional* ( parser -- parser ) optional*-parser boa wrap-peg ;