package re

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RE is a regular expression library for OCaml

Install 

dune-project
 Dependency

github.com Readme Changelog LGPL-2.1-or-later WITH OCaml-LGPL-linking-exception License Edit opam file Versions (20)

Authors

  1. J
    Jerome Vouillon
  2. T
    Thomas Gazagnaire
  3. A
    Anil Madhavapeddy
  4. R
    Rudi Grinberg
  5. Gabriel Radanne

Maintainers

  1. R
    Rudi Grinberg <me@rgrinberg.com>

Sources

1.14.0.tar.gz
md5=03f4a83100cb9229a796b85c698076e1
sha512=cd2cc39f951ca6b7be631bbb5531ed13bc040e629842671bf6fef3911b20ef1653fa9a1f0aa23b094d252cffc9a9efe7ffca69e50d362ab935bc0cc447548124

Description

Pure OCaml regular expressions with:

  • Perl-style regular expressions (module Re.Perl)
  • Posix extended regular expressions (module Re.Posix)
  • Emacs-style regular expressions (module Re.Emacs)
  • Shell-style file globbing (module Re.Glob)
  • Compatibility layer for OCaml's built-in Str module (module Re.Str)

Added to opam-repository:

README

Description

Re is a regular expression library for OCaml. Build status

Contact

This library has been written by Jerome Vouillon (Jerome.Vouillon@pps.univ-paris-diderot.fr). It can be downloaded from https://github.com/ocaml/ocaml-re

Bug reports, suggestions and contributions are welcome.

Features

The following styles of regular expressions are supported:

  • Perl-style regular expressions (module Re.Perl);
  • Posix extended regular expressions (module Re.Posix);
  • Emacs-style regular expressions (module Re.Emacs);
  • Shell-style file globbing (module Re.Glob).

It is also possible to build regular expressions by combining simpler regular expressions (module Re).

The most notable missing features are back-references and look-ahead/look-behind assertions.

There is also a subset of the PCRE interface available in the Re.Pcre module. This makes it easier to port code from that library to Re with minimal changes.

Performances

The matches are performed by lazily building a DFA (deterministic finite automaton) from the regular expression. As a consequence, matching takes linear time in the length of the matched string.

The compilation of patterns is slower than with libraries using back-tracking, such as PCRE. But, once a large enough part of the DFA is built, matching is extremely fast.

Of course, for some combinations of regular expression and string, the part of the DFA that needs to be build is so large that this point is never reached, and matching will be slow. This is not expected to happen often in practice, and actually a lot of expressions that behaves badly with a backtracking implementation are very efficient with this implementation.

The library is at the moment entirely written in OCaml. As a consequence, regular expression matching is much slower when the library is compiled to bytecode than when it is compiled to native code.

Here are some timing results (Pentium III 500Mhz):

  • Scanning a 1Mb string containing only as, except for the last character which is a b, searching for the pattern aa?b (repeated 100 times):

    • RE: 2.6s
    • PCRE: 68s

  • Regular expression example from http://www.bagley.org/~doug/shootout/ [1]

    • RE: 0.43s
    • PCRE: 3.68s

    [1] this page is no longer up but is available via the Internet Archive http://web.archive.org/web/20010429190941/http://www.bagley.org/~doug/shootout/bench/regexmatch/

  • The large regular expression (about 2000 characters long) that Unison uses with my preference file to decide whether a file should be ignored or not. This expression is matched against a filename about 20000 times.

    • RE: 0.31s
    • PCRE: 3.7s However, RE is only faster than PCRE when there are more than about 300 filenames.

Dependencies (2)

  1. ocaml >= "4.13.0"
  2. dune >= "3.17"

Dev Dependencies (5)

  1. odoc with-doc
  2. conf-npm with-test
  3. js_of_ocaml with-test
  4. ounit2 with-test
  5. ppx_expect with-test & >= "v0.17.0"

Optional Dependencies

None

  1. alcobar >= "0.5.0"
  2. alcotest
  3. alcotest-async
  4. alcotest-lwt
  5. alcotest-mirage
  6. alice
  7. atd >= "2.2.1"
  8. atd-jsonlike
  9. atdcpp
  10. atdd
  11. atdgen >= "2.3.3"
  12. atdgen-runtime = "2.2.1"
  13. atdj >= "2.2.1"
  14. atdpy >= "2.4.1"
  15. atds < "2.3.3"
  16. atdts
  17. aws-config
  18. awsm-codegen
  19. awso
  20. BetterErrors
  21. bancos
  22. bap-byteweight-frontend
  23. bap-callgraph-collator
  24. bap-fsi-benchmark
  25. bap-ida
  26. bap-objdump
  27. bap-print
  28. bap-radare2
  29. bibfmt
  30. bio_io >= "0.5.1"
  31. biocaml
  32. bonsai >= "v0.15.0"
  33. brot
  34. caisar >= "4.0"
  35. calculon
  36. calculon-web
  37. caldav
  38. calendar >= "3.0.0"
  39. camlp5 >= "8.02.01"
  40. camlp5-buildscripts
  41. camyll
  42. caqti >= "1.7.0"
  43. cascade
  44. catala
  45. catala-format >= "1.2.0"
  46. chamo
  47. ciao_lwt
  48. cinaps
  49. cohttp
  50. coin < "0.1.5"
  51. colibri2
  52. commons
  53. conan >= "0.0.6"
  54. console
  55. core_bench
  56. core_extended
  57. cosovo
  58. cowabloga >= "0.4.0"
  59. crs
  60. cucumber
  61. cuid
  62. current
  63. current_web
  64. daypack-lib
  65. debian-formats
  66. decompress < "1.0.0"
  67. dns < "4.4.1"
  68. docfd >= "13.0.0"
  69. doi2bib
  70. dose3
  71. dune-glob >= "3.21.0"
  72. dune-release >= "0.2.0"
  73. dune-rpc >= "3.25.0"
  74. dunolint >= "0.0.20251006"
  75. dunolint-lib
  76. dunolint-lib-base
  77. duppy >= "0.9.5"
  78. eliom >= "13.0.0"
  79. elpi
  80. expect >= "0.1.0"
  81. expect_test_helpers_core
  82. expect_test_helpers_kernel
  83. ez_file
  84. ez_search
  85. fat-filesystem
  86. git-split < "1.0.0"
  87. gpiod
  88. graphql_parser >= "0.11.0"
  89. hardcaml_verify
  90. hardcaml_waveterm
  91. hardcaml_xilinx_components
  92. hegel >= "0.24.1"
  93. hlarp >= "0.0.3"
  94. humane-re
  95. icalendar
  96. index
  97. index-bench
  98. irmin-bench
  99. jingoo >= "1.2.21"
  100. js_of_ocaml >= "3.10.0"
  101. js_of_ocaml-compiler >= "3.10.0"
  102. js_of_ocaml-lwt >= "3.10.0"
  103. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  104. js_of_ocaml-ppx >= "3.10.0"
  105. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  106. js_of_ocaml-toplevel >= "3.10.0"
  107. js_of_ocaml-tyxml >= "3.10.0"
  108. jsonschema
  109. jsonschema-core
  110. jsonschema-validation
  111. jwt
  112. jwto
  113. k7
  114. kappa-library
  115. kubecaml
  116. lastfm >= "0.3.4"
  117. ldap >= "2.5.1"
  118. learn-ocaml
  119. ledes
  120. lipsum
  121. liquidsoap >= "2.3.3" & < "2.4.2"
  122. liquidsoap-core >= "2.3.0"
  123. liquidsoap-lang >= "2.3.0"
  124. lwt_ppx_to_let_syntax
  125. MlFront_Cli >= "2.1.4~prerel2" & < "2.3.1"
  126. MlFront_Core >= "2.4.2.30"
  127. MlFront_ZipFile
  128. magic-trace
  129. mdx
  130. mehari < "0.5"
  131. menhir-lsp >= "0.1.2"
  132. menhirformat
  133. mnet-cli >= "0.0.3" & < "0.0.8"
  134. mparser-re
  135. naboris
  136. netsnmp
  137. ninja_utils
  138. nx-text
  139. obelisk >= "0.5.0"
  140. ocaml-lsp-server >= "1.9.0"
  141. ocamlformat
  142. ocamlformat-mlx
  143. ocamlformat-rpc < "0.21.0"
  144. ocamlmig
  145. ocgtk < "0.1~preview2"
  146. ocp-build
  147. ocp-index
  148. ocsigen-start
  149. ocsigenserver >= "5.1.0"
  150. opam-bin >= "0.9.5" & < "1.1.0"
  151. opam-client < "2.6.0~alpha1"
  152. opam-compiler
  153. opam-core
  154. opam-format >= "2.0.8" & != "2.1.0~beta4" & < "2.6.0~alpha1"
  155. opam-lib
  156. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0" & < "2.6.0~alpha1"
  157. opam-state >= "2.2.0" & < "2.6.0~alpha1"
  158. opam_bin_lib
  159. opium
  160. opium_kernel
  161. oranger
  162. orun
  163. ostap
  164. oxbow
  165. ozulip
  166. pa_ppx_parsetree
  167. pa_ppx_regexp >= "0.04"
  168. pa_ppx_string
  169. parseff
  170. passage >= "0.3.2"
  171. patdiff
  172. pgocaml >= "2.3"
  173. pgx
  174. plato
  175. playwright
  176. podge >= "0.3"
  177. ppx_css < "v0.17.0"
  178. ppx_cstubs
  179. ppx_elpi
  180. ppx_expect < "v0.17.0"
  181. ppx_expect_nobase = "v0.17.2.2"
  182. ppx_mikmatch
  183. ppx_minidebug >= "1.6.0"
  184. ppx_regexp >= "0.3.2"
  185. ppx_test
  186. ppx_tyre
  187. ppxlib >= "0.21.1"
  188. prometheus >= "0.2"
  189. prometheus-app < "2.0"
  190. prometheus-reporter
  191. pyml_bindgen >= "0.3.1"
  192. raga
  193. rdf
  194. re_parser
  195. redis
  196. regrade
  197. rfc1951 < "1.0.0"
  198. safemoney >= "0.3.0"
  199. saga
  200. sarek
  201. sarif >= "0.2.1"
  202. satyrographos
  203. semantic_version
  204. sexp_pretty
  205. shakuhachi
  206. simple-diff
  207. slug
  208. smtml >= "0.21.0"
  209. snf_mcp
  210. sosie
  211. soupault
  212. spectrum >= "0.7.0"
  213. spectrum_capabilities
  214. spectrum_palette_ppx
  215. spectrum_tools
  216. spoc
  217. statocaml_profile
  218. stem
  219. swagger
  220. talon < "1.0.0~alpha3"
  221. testcontainers
  222. testo
  223. testo-lwt
  224. testo-util
  225. tezt
  226. timere-parse
  227. touist >= "3.5.0"
  228. tw
  229. tyre >= "0.4"
  230. tyxml >= "4.2.0"
  231. tyxml-ppx >= "5.0.0"
  232. tyxml-syntax
  233. unic
  234. uri < "4.0.0"
  235. uri-re
  236. user-agent-parser
  237. user-setup
  238. uuuu < "0.4.0"
  239. validate
  240. vendredi
  241. wasm_of_ocaml-compiler
  242. wax-lib
  243. webmachine
  244. wire
  245. xtmpl >= "0.18.0"

Conflicts

None

Build status

Results of building re with each compiler on check.ci.ocaml.org, run of against opam-repository 78c202b. All results for this package.

Each result links to its build log. To keep crawlers from overloading the site, build logs require a GitHub sign-in (see ocurrent/opam-health-check). On your first log, GitHub asks you to “Authorize opam-health-check”, the OCurrent app that runs these checks; it sees only your public profile, not your repositories. The sign-in lasts 30 days.

Version OCaml 4.11 OCaml 4.14 OCaml 5.2 OCaml 5.4 OCaml 5.5
1.14.0 (this version) n/a good good good good
1.11.0 good good good good good
  • good Package successfully built
  • partial One of the dependencies failed to build
  • bad Package failed to build
  • n/a Package is not available in this environment
  • internal Internal failure