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. core_bench
  53. core_extended
  54. cosovo
  55. cowabloga >= "0.4.0"
  56. cucumber
  57. cuid
  58. current
  59. current_web
  60. daypack-lib
  61. debian-formats
  62. decompress < "1.0.0"
  63. dns < "4.4.1"
  64. docfd >= "13.0.0"
  65. doi2bib
  66. dose3
  67. dune-glob >= "3.21.0"
  68. dune-release >= "0.2.0"
  69. dunolint >= "0.0.20251006"
  70. dunolint-lib
  71. dunolint-lib-base
  72. duppy >= "0.9.5"
  73. elpi
  74. expect_test_helpers_core
  75. expect_test_helpers_kernel
  76. ez_file
  77. ez_search
  78. fat-filesystem
  79. git-split < "1.0.0"
  80. gpiod
  81. graphql_parser >= "0.11.0"
  82. hardcaml_verify
  83. hardcaml_waveterm
  84. hardcaml_xilinx_components
  85. hlarp >= "0.0.3"
  86. humane-re
  87. icalendar
  88. index
  89. index-bench
  90. irmin-bench
  91. jingoo >= "1.2.21"
  92. js_of_ocaml >= "3.10.0"
  93. js_of_ocaml-compiler >= "3.10.0"
  94. js_of_ocaml-lwt >= "3.10.0"
  95. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  96. js_of_ocaml-ppx >= "3.10.0"
  97. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  98. js_of_ocaml-toplevel >= "3.10.0"
  99. js_of_ocaml-tyxml >= "3.10.0"
  100. jsonschema
  101. jsonschema-core
  102. jsonschema-validation
  103. jwt
  104. jwto
  105. k7
  106. kappa-agents >= "4.1.3"
  107. kappa-binaries >= "4.1.3"
  108. kappa-library
  109. kubecaml
  110. lastfm >= "0.3.4"
  111. ldap >= "2.5.1"
  112. learn-ocaml
  113. ledes
  114. lipsum
  115. liquidsoap >= "2.3.3"
  116. liquidsoap-core >= "2.3.0"
  117. liquidsoap-lang >= "2.3.0"
  118. lwt_ppx_to_let_syntax
  119. MlFront_Cli >= "2.1.4~prerel2" & < "2.3.1"
  120. MlFront_Core >= "2.4.2.30"
  121. MlFront_ZipFile
  122. magic-trace
  123. mdx
  124. mehari
  125. mnet-cli >= "0.0.3" & < "0.0.8"
  126. mparser-re
  127. naboris
  128. netsnmp
  129. ninja_utils
  130. nx-text
  131. obelisk >= "0.5.0"
  132. ocaml-lsp-server >= "1.9.0"
  133. ocamlformat
  134. ocamlformat-mlx
  135. ocamlformat-rpc < "0.21.0"
  136. ocamlmig
  137. ocgtk < "0.1~preview2"
  138. ocp-build
  139. ocp-index
  140. ocsigen-start
  141. ocsigenserver >= "5.1.0"
  142. opam-bin >= "0.9.5" & < "1.1.0"
  143. opam-client < "2.6.0~alpha1"
  144. opam-compiler
  145. opam-core
  146. opam-format >= "2.0.8" & != "2.1.0~beta4" & < "2.6.0~alpha1"
  147. opam-lib
  148. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0" & < "2.6.0~alpha1"
  149. opam-state >= "2.2.0" & < "2.6.0~alpha1"
  150. opam_bin_lib
  151. opium
  152. opium_kernel
  153. oranger
  154. orun
  155. ostap
  156. ozulip
  157. pa_ppx_parsetree
  158. pa_ppx_regexp < "0.04"
  159. pa_ppx_string
  160. parseff
  161. patdiff
  162. pgocaml >= "2.3"
  163. pgx
  164. plato
  165. playwright
  166. podge >= "0.3"
  167. ppx_css < "v0.17.0"
  168. ppx_cstubs
  169. ppx_elpi
  170. ppx_expect < "v0.17.0"
  171. ppx_expect_nobase = "v0.17.2.2"
  172. ppx_mikmatch
  173. ppx_minidebug >= "1.6.0"
  174. ppx_regexp >= "0.3.2"
  175. ppx_test
  176. ppx_tyre
  177. ppxlib >= "0.21.1"
  178. prometheus >= "0.2"
  179. prometheus-app < "2.0"
  180. prometheus-reporter
  181. pyml_bindgen >= "0.3.1"
  182. raga
  183. rdf
  184. re_parser
  185. redis
  186. regrade
  187. rfc1951 < "1.0.0"
  188. safemoney >= "0.3.0"
  189. saga
  190. sarek
  191. sarif >= "0.2.1"
  192. satyrographos
  193. semantic_version
  194. sexp_pretty
  195. shakuhachi
  196. simple-diff
  197. slug
  198. smtml >= "0.21.0"
  199. snf_mcp
  200. sosie
  201. soupault
  202. spectrum >= "0.7.0"
  203. spectrum_capabilities
  204. spectrum_palette_ppx
  205. spectrum_tools
  206. spoc
  207. stem
  208. swagger
  209. talon < "1.0.0~alpha3"
  210. testcontainers
  211. testo
  212. testo-lwt
  213. testo-util
  214. tezt
  215. timere-parse
  216. touist >= "3.5.0"
  217. tw < "1.1.0"
  218. tyre >= "0.4"
  219. tyxml >= "4.2.0"
  220. tyxml-ppx >= "5.0.0"
  221. tyxml-syntax
  222. unic
  223. uri < "4.0.0"
  224. uri-re
  225. user-agent-parser
  226. user-setup
  227. uuuu < "0.4.0"
  228. validate
  229. vendredi
  230. wasm_of_ocaml-compiler
  231. wax-lib
  232. webmachine
  233. wire
  234. xtmpl >= "0.18.0"

Conflicts

None