ensure ( parser -- parser )

Vocabulary
peg

Inputs

parser

Outputs

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 ;