lang-evolve-rs/README.org

#+title: LangEvolve-rs
#+author: Lucien Cartier-Tilet

* Introduction
  LangEvolve-rs is a Rust rewrite of  the original [[https://github.com/ceronyon/LangEvolve/][LangEvolve project]] written by
  [[https://github.com/ceronyon/LangEvolve/][Ceronyon]]. This tool is  a conlanging tool used to apply  sound change rules on
  words or text.

* Differences with the original project
  The main  difference with  the main  project resides  in its  settings format:
  while  the  original project  only  supports  the  JSON format,  this  project
  supports both the JSON and the Yaml formats. The settings are also represented
  differently in  JSON between the  original project  and this one.  Lastly, the
  regex crate used  in this project does not allow  certain expressions, such as
  look-ahead and look-behind searches, and  backreferences. To get a better idea
  of what  I am talking about,  here is the  example json given by  the original
  project for Latin to Portugese:
  #+BEGIN_SRC json
    {
      "version" : "1",
      "categories" : {
        "V" : "aeiou",
        "L" : "āēīōū",
        "C" : "ptcqbdgmnlrhs",
        "F" : "ie",
        "B" : "ou",
        "S" : "ptc",
        "Z" : "bdg"
      },
      "rules" : [
        { "[sm]$" : "" },
        { "i(%V)" : "j\\1" },
        { "%L" : "%V" },
        { "(%Vr)e$" : "\\1" },
        { "(%V)v(%V)" : "\\1\\2" },
        { "u$" : "o" },
        { "gn" : "nh" },
        { "(%V)p(?=%V)" : "\\1b" },
        { "(%V)t(?=%V)" : "\\1d" },
        { "(%V)c(?=%V)" : "\\1g" },
        { "(%F)ct" : "\\1it" },
        { "(%B)ct" : "\\1ut" },
        { "(%V)pt" : "\\1t" },
        { "ii" : "i" },
        { "(%C)er(%V)" : "\\1r\\2" },
        { "lj" : "lh" }
      ]
    }
  #+END_SRC

  As you  can see, backreferences have  their syntax modified from ~\1~ to ~$1~
  for instance, and look-ahead and  look-behind expressions must be incorporated
  into the expression.

  And here is the JSON generated by this project (beautified, the original is on
  one line only without unnecessary whitespace):
  #+BEGIN_SRC json
    {
        "version": "1",
        "categories": {
            "S": "ptc",
            "L": "āēīōū",
            "V": "aeiou",
            "Z": "bgd",
            "F": "ie",
            "C": "ptcqbdgmnlrhs",
            "B": "ou"
        },
        "rules": [
            ["[sm]$", ""],
            ["i(%V)", "j$1"],
            ["%L", "%V"],
            ["(%Vr)e$", "$1"],
            ["(%V)v(%V)", "${1}$2"],
            ["u$", "o"],
            ["gn", "nh"],
            ["(%V)p(%V)", "${1}b$2"],
            ["(%V)t(%V)", "${1}d$2"],
            ["(%V)c(%V)", "${1}g$2"],
            ["(%F)ct", "${1}it"],
            ["(%B)ct", "${1}ut"],
            ["(%V)pt", "${1}t"],
            ["ii", "i"],
            ["(%C)er(%V)", "${1}r$2"],
            ["lj", "lh"]
        ]
    }
  #+END_SRC

  By the way, here is the Yaml equivalent generated by this project:
  #+BEGIN_SRC yaml
    ---
    version: "1"
    categories:
      B: ou
      S: ptc
      L: āēīōū
      Z: bgd
      C: ptcqbdgmnlrhs
      F: ie
      V: aeiou
    rules:
      - - "[sm]$"
        - ""
      - - i(%V)
        - j$1
      - - "%L"
        - "%V"
      - - (%Vr)e$
        - $1
      - - (%V)v(%V)
        - "${1}$2"
      - - u$
        - o
      - - gn
        - nh
      - - (%V)p(%V)
        - "${1}b$2"
      - - (%V)t(%V)
        - "${1}d$2"
      - - (%V)c(%V)
        - "${1}g$2"
      - - (%F)ct
        - "${1}it"
      - - (%B)ct
        - "${1}ut"
      - - (%V)pt
        - "${1}t"
      - - ii
        - i
      - - (%C)er(%V)
        - "${1}r$2"
      - - lj
        - lh
  #+END_SRC

  Although most of the rules are not  between double quotes, it is preferable to
  write them as follows in order to avoid any issues with LangEvolveRs:
  #+BEGIN_SRC yaml
    ---
    version: "1"
    categories:
      B: ou
      S: ptc
      L: āēīōū
      Z: bgd
      C: ptcqbdgmnlrhs
      F: ie
      V: aeiou
    rules:
      - - "[sm]$"
        - ""
      - - "i(%V)"
        - "j$1"
      - - "%L"
        - "%V"
      - - "(%Vr)e$"
        - "$1"
      - - "(%V)v(%V)"
        - "${1}$2"
      - - "u$"
        - "o"
      - - "gn"
        - "nh"
      - - "(%V)p(%V)"
        - "${1}b$2"
      - - "(%V)t(%V)"
        - "${1}d$2"
      - - "(%V)c(%V)"
        - "${1}g$2"
      - - "(%F)ct"
        - "${1}it"
      - - "(%B)ct"
        - "${1}ut"
      - - "(%V)pt"
        - "${1}t"
      - - "ii"
        - "i"
      - - "(%C)er(%V)"
        - "${1}r$2"
      - - "lj"
        - "lh"
  #+END_SRC

  You can  find more  information on  how to use  regular expressions  with this
  project in the documentation of the regex crate [[https://docs.rs/regex/1.3.6/regex/][here]].

* License
  LangEvolveRs is  licensed under the  AGPLv3 license.  The full license  can be
  found [[file:agpl-3.0.txt][here]].