LangEvolve-rs

• Introduction
• Differences with the original project
• License

Introduction

LangEvolve-rs is a Rust rewrite of the original LangEvolve project written by 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:

  {
    "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" }
    ]
  }

As you can see, backreferences have their syntax modified from \1 to $1 (or ${1} if it is followed by other stuff) 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):

  {
      "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"]
      ]
  }

By the way, here is the Yaml equivalent generated by this project:

  ---
  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

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:

  ---
  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"

You can find more information on how to use regular expressions with this project in the documentation of the regex crate here.

The settings schema is set to be fully backward-compatible. This means if the version number goes up in the settings file, older settings file will remain compatible with newer versions of the software. However, forward compatibility cannot be ensured unless someone invents time travel, hence settings files with a higher version than the running software’s will be automatically rejected.

License

LangEvolveRs is licensed under the AGPLv3 license. The full license can be found here.