package re

  1. Overview
  2. Docs
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@gmail.com

Sources

re-1.11.0.tbz
sha256=01fc244780c0f6be72ae796b1fb750f367de18624fd75d07ee79782ed6df8d4f
sha512=3e3712cc1266ec1f27620f3508ea2ebba338f4083b07d8a69dccee1facfdc1971a6c39f9deea664d2a62fd7f2cfd2eae816ca4c274acfadaee992a3befc4b757

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 (3)

  1. seq
  2. dune >= "2.0"
  3. ocaml >= "4.03"

Dev Dependencies (1)

  1. ounit with-test

  1. alcotest
  2. alcotest-async
  3. alcotest-lwt
  4. alcotest-mirage
  5. atd >= "2.2.1"
  6. atd-jsonlike
  7. atdcpp
  8. atdd
  9. atdgen >= "2.3.3"
  10. atdgen-runtime = "2.2.1"
  11. atdj >= "2.2.1"
  12. atdpy >= "2.4.1"
  13. atds < "2.3.3"
  14. atdts
  15. aws-config
  16. awsm-codegen
  17. awso
  18. BetterErrors
  19. bancos
  20. bap-byteweight-frontend
  21. bap-callgraph-collator
  22. bap-fsi-benchmark
  23. bap-ida
  24. bap-objdump
  25. bap-print
  26. bap-radare2
  27. bibfmt
  28. bio_io >= "0.5.1"
  29. biocaml
  30. bonsai >= "v0.15.0"
  31. brot
  32. caisar < "4.0"
  33. calculon
  34. calculon-web
  35. caldav
  36. calendar >= "3.0.0"
  37. camlp5 >= "8.02.01"
  38. camlp5-buildscripts
  39. camyll
  40. caqti >= "1.7.0"
  41. cascade
  42. catala
  43. catala-format >= "1.2.0"
  44. chamo
  45. ciao_lwt
  46. cinaps
  47. cohttp
  48. coin < "0.1.5"
  49. colibri2
  50. commons
  51. conan = "0.0.5"
  52. console
  53. core_bench
  54. core_extended
  55. cosovo
  56. cowabloga >= "0.4.0"
  57. cucumber
  58. cuid
  59. current
  60. current_web
  61. daypack-lib
  62. debian-formats
  63. decompress < "1.0.0"
  64. dns < "4.4.1"
  65. docfd >= "13.0.0"
  66. doi2bib
  67. dose3
  68. dune-glob >= "3.21.0"
  69. dune-release >= "0.2.0"
  70. dunolint >= "0.0.20251006"
  71. dunolint-lib
  72. dunolint-lib-base
  73. duppy >= "0.9.5"
  74. elpi
  75. expect_test_helpers_core
  76. expect_test_helpers_kernel
  77. ez_file
  78. ez_search
  79. fat-filesystem
  80. git-split < "1.0.0"
  81. gpiod
  82. graphql_parser >= "0.11.0"
  83. hardcaml_verify
  84. hardcaml_waveterm
  85. hardcaml_xilinx_components
  86. hlarp >= "0.0.3"
  87. humane-re
  88. icalendar
  89. index
  90. index-bench
  91. irmin-bench
  92. jingoo >= "1.2.21"
  93. js_of_ocaml >= "3.10.0"
  94. js_of_ocaml-compiler >= "3.10.0"
  95. js_of_ocaml-lwt >= "3.10.0"
  96. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  97. js_of_ocaml-ppx >= "3.10.0"
  98. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  99. js_of_ocaml-toplevel >= "3.10.0"
  100. js_of_ocaml-tyxml >= "3.10.0"
  101. jsonschema
  102. jsonschema-core
  103. jsonschema-validation
  104. jwt
  105. jwto
  106. k7
  107. kappa-agents >= "4.1.3"
  108. kappa-binaries >= "4.1.3"
  109. kappa-library
  110. kubecaml
  111. lastfm >= "0.3.4"
  112. ldap >= "2.5.1"
  113. learn-ocaml
  114. ledes
  115. lipsum
  116. liquidsoap >= "2.3.3"
  117. liquidsoap-core >= "2.3.0"
  118. liquidsoap-lang >= "2.3.0"
  119. lwt_ppx_to_let_syntax
  120. MlFront_Cli >= "2.1.4~prerel2" & < "2.3.1"
  121. MlFront_Core >= "2.4.2.30"
  122. MlFront_ZipFile
  123. magic-trace
  124. mdx
  125. mehari
  126. mnet-cli >= "0.0.3" & < "0.0.8"
  127. mparser-re
  128. naboris
  129. netsnmp
  130. ninja_utils
  131. nx-text
  132. obelisk >= "0.5.0"
  133. ocaml-lsp-server >= "1.9.0"
  134. ocamlformat
  135. ocamlformat-mlx
  136. ocamlformat-rpc < "0.21.0"
  137. ocamlmig
  138. ocgtk < "0.1~preview2"
  139. ocp-build
  140. ocp-index
  141. ocsigen-start
  142. ocsigenserver >= "5.1.0"
  143. opam-bin >= "0.9.5" & < "1.1.0"
  144. opam-client < "2.6.0~alpha1"
  145. opam-compiler
  146. opam-core
  147. opam-format >= "2.0.8" & != "2.1.0~beta4" & < "2.6.0~alpha1"
  148. opam-lib
  149. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0" & < "2.6.0~alpha1"
  150. opam-state >= "2.2.0" & < "2.6.0~alpha1"
  151. opam_bin_lib
  152. opium
  153. opium_kernel
  154. oranger
  155. orun
  156. ostap
  157. ozulip
  158. pa_ppx_parsetree
  159. pa_ppx_regexp < "0.04"
  160. pa_ppx_string
  161. parseff
  162. patdiff
  163. pgocaml >= "2.3"
  164. pgx
  165. plato
  166. playwright
  167. podge >= "0.3"
  168. ppx_css < "v0.17.0"
  169. ppx_cstubs
  170. ppx_elpi
  171. ppx_expect < "v0.17.0"
  172. ppx_expect_nobase = "v0.17.2.2"
  173. ppx_mikmatch
  174. ppx_minidebug >= "1.6.0"
  175. ppx_regexp >= "0.3.2"
  176. ppx_test
  177. ppx_tyre
  178. ppxlib >= "0.21.1"
  179. prometheus >= "0.2"
  180. prometheus-app < "2.0"
  181. prometheus-reporter
  182. pyml_bindgen >= "0.3.1"
  183. raga
  184. rdf
  185. re_parser
  186. redis
  187. regrade
  188. rfc1951 < "1.0.0"
  189. safemoney >= "0.3.0"
  190. saga
  191. sarek
  192. sarif >= "0.2.1"
  193. satyrographos
  194. semantic_version
  195. sexp_pretty
  196. shakuhachi
  197. simple-diff
  198. slug
  199. smtml >= "0.21.0"
  200. snf_mcp
  201. sosie
  202. soupault
  203. spectrum >= "0.7.0"
  204. spectrum_capabilities
  205. spectrum_palette_ppx
  206. spectrum_tools
  207. spoc
  208. stem
  209. swagger
  210. talon < "1.0.0~alpha3"
  211. testcontainers
  212. testo
  213. testo-lwt
  214. testo-util
  215. tezt
  216. timere-parse
  217. touist >= "3.5.0"
  218. tw < "1.1.0"
  219. tyre >= "0.4"
  220. tyxml >= "4.2.0"
  221. tyxml-ppx >= "5.0.0"
  222. tyxml-syntax
  223. unic
  224. uri < "4.0.0"
  225. uri-re
  226. user-agent-parser
  227. user-setup
  228. uuuu < "0.4.0"
  229. validate
  230. vendredi
  231. wasm_of_ocaml-compiler
  232. wax-lib
  233. webmachine
  234. wire
  235. xtmpl >= "0.18.0"

Conflicts

None