Function builtin_charmatch 

fn builtin_charmatch(
    args: &[RValue],
    _: &[(String, RValue)],
) -> Result<RValue, RError>

Character partial matching — like pmatch but returns 0 for ambiguous matches.

For each element of x, returns the position of its unique partial match in table. Returns NA for no match, and 0 for ambiguous matches (multiple partial matches).

@param x values to look up @param table values to match against @return integer vector of match positions (1-indexed), 0 for ambiguous, NA for no match