ensure ( parser -- parser )

Vocabulary

peg

Inputs

parser

a parser

Outputs

parser

a parser

Word description

Returns a parser that succeeds if the parser succeeds but does not add anything to the AST and does not move the location in the input string. This can be used for lookahead and disambiguation, along with the ensure-not word.

Examples

"0" token ensure octal-parser

Definition

USING: kernel peg.private ;

IN: peg

: ensure ( parser -- parser ) ensure-parser boa wrap-peg ;