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