Skip to contents

Describe compiled patterns

Source: R/compile.R
re_info.Rd

Reports what PCRE2 recorded when it compiled each pattern.

Usage

re_info(re)

Arguments

re

An re vector from re_compile().

Value

A data frame with one row per pattern and columns:

  • pattern, flags, dialect, literal: what was compiled. flags is rebuilt from PCRE2's options, in a canonical order.

  • groups: the number of capture groups.

  • group_names: a list column; for each pattern, a character vector with one name per group, "" for unnamed groups.

  • jit: whether the pattern runs JIT-compiled code.

  • min_length: a lower bound on the length of a match, in characters.

  • prefix: a literal string every match starts with, "" when there is none or it cannot be determined simply. It may be shorter than the longest such string.

  • backrefs: whether the pattern has back-references.

  • pcre2_version: the PCRE2 version that compiled it.

An NA pattern gives a row of NA.

Examples

re_info(re_compile(c("(?<year>\\d{4})-(\\d{2})", "abc+")))
#>                    pattern flags dialect literal groups group_names  jit
#> 1 (?<year>\\d{4})-(\\d{2})          pcre   FALSE      2      year,  TRUE
#> 2                     abc+          pcre   FALSE      0             TRUE
#>   min_length prefix backrefs pcre2_version
#> 1          7           FALSE         10.48
#> 2          3     ab    FALSE         10.48