package re

  1. Overview
  2. Docs
RE is a regular expression library for OCaml

Install 

dune-project
 Dependency

github.com Readme Changelog LGPL-2.0-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-1.10.4.tbz
sha256=83eb3e4300aa9b1dc7820749010f4362ea83524742130524d78c20ce99ca747c
sha512=92b05cf92c389fa8c753f2acca837b15dd05a4a2e8e2bec7a269d2e14c35b1a786d394258376648f80b4b99250ba1900cfe68230b8385aeac153149d9ce56099

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 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-buildscripts
  38. camyll
  39. caqti >= "1.7.0"
  40. cascade
  41. catala < "1.0.0~beta"
  42. chamo
  43. ciao_lwt
  44. cinaps
  45. cohttp
  46. coin < "0.1.5"
  47. colibri2
  48. commons
  49. conan < "0.0.5"
  50. core_bench
  51. core_extended
  52. cosovo
  53. cowabloga >= "0.4.0"
  54. cucumber
  55. cuid
  56. current
  57. current_web
  58. daypack-lib
  59. debian-formats
  60. decompress < "1.0.0"
  61. dns < "4.4.1"
  62. doi2bib
  63. dose3
  64. dune-glob >= "3.21.0"
  65. dune-release >= "0.2.0"
  66. dunolint >= "0.0.20251006"
  67. dunolint-lib
  68. dunolint-lib-base
  69. duppy >= "0.9.5"
  70. elpi
  71. expect_test_helpers_core
  72. expect_test_helpers_kernel
  73. ez_file
  74. ez_search
  75. fat-filesystem
  76. git-split < "1.0.0"
  77. gpiod
  78. graphql_parser >= "0.11.0"
  79. hardcaml_verify
  80. hardcaml_waveterm
  81. hardcaml_xilinx_components
  82. hlarp >= "0.0.3"
  83. humane-re
  84. icalendar
  85. index
  86. index-bench
  87. irmin-bench
  88. jingoo >= "1.2.21"
  89. js_of_ocaml >= "3.10.0"
  90. js_of_ocaml-compiler >= "3.10.0"
  91. js_of_ocaml-lwt >= "3.10.0"
  92. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  93. js_of_ocaml-ppx >= "3.10.0"
  94. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  95. js_of_ocaml-toplevel >= "3.10.0"
  96. js_of_ocaml-tyxml >= "3.10.0"
  97. jsonschema
  98. jsonschema-core
  99. jsonschema-validation
  100. jwt
  101. jwto
  102. kappa-library
  103. kubecaml
  104. ldap >= "2.5.1"
  105. learn-ocaml
  106. ledes
  107. lipsum
  108. lwt_ppx_to_let_syntax
  109. magic-trace
  110. mdx
  111. mehari
  112. mnet-cli >= "0.0.3"
  113. mparser-re
  114. naboris
  115. netsnmp
  116. ninja_utils
  117. nx-text
  118. obelisk >= "0.5.0"
  119. ocaml-lsp-server >= "1.9.0"
  120. ocamlformat
  121. ocamlformat-mlx
  122. ocamlformat-rpc < "0.21.0"
  123. ocamlmig
  124. ocgtk < "0.1~preview2"
  125. ocp-build
  126. ocp-index
  127. ocsigen-start
  128. opam-bin >= "0.9.5" & < "1.1.0"
  129. opam-client < "2.6.0~alpha1"
  130. opam-compiler
  131. opam-core
  132. opam-format >= "2.0.8" & != "2.1.0~beta4" & < "2.6.0~alpha1"
  133. opam-lib
  134. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0" & < "2.6.0~alpha1"
  135. opam-state >= "2.2.0" & < "2.6.0~alpha1"
  136. opam_bin_lib
  137. opium
  138. opium_kernel
  139. oranger
  140. ostap
  141. ozulip
  142. pa_ppx_string
  143. parseff
  144. patdiff
  145. pgocaml >= "2.3"
  146. pgx
  147. plato
  148. playwright
  149. podge >= "0.3"
  150. ppx_css < "v0.17.0"
  151. ppx_cstubs
  152. ppx_expect < "v0.17.0"
  153. ppx_expect_nobase = "v0.17.2.2"
  154. ppx_mikmatch
  155. ppx_minidebug >= "1.6.0"
  156. ppx_regexp >= "0.3.2"
  157. ppx_test
  158. ppx_tyre
  159. ppxlib >= "0.21.1"
  160. prometheus >= "0.2"
  161. prometheus-app
  162. pyml_bindgen >= "0.3.1"
  163. raga
  164. rdf < "1.0.0"
  165. re_parser
  166. redis
  167. rfc1951 < "1.0.0"
  168. safemoney >= "0.3.0"
  169. saga
  170. sarek
  171. sarif >= "0.2.1"
  172. satyrographos
  173. semantic_version
  174. sexp_pretty
  175. shakuhachi
  176. simple-diff
  177. slug
  178. smtml >= "0.21.0"
  179. snf_mcp
  180. soupault
  181. spoc
  182. stem
  183. swagger
  184. talon < "1.0.0~alpha3"
  185. testo
  186. testo-lwt
  187. testo-util
  188. tezt
  189. timere-parse
  190. touist >= "3.5.0"
  191. tw
  192. tyre >= "0.4"
  193. tyxml >= "4.2.0"
  194. tyxml-syntax
  195. uri < "4.0.0"
  196. uri-re
  197. user-agent-parser
  198. user-setup
  199. uuuu < "0.4.0"
  200. validate
  201. vendredi
  202. wasm_of_ocaml-compiler
  203. wax-lib
  204. webmachine
  205. wire < "1.0.0"
  206. xtmpl >= "0.18.0"

Conflicts

None