barg-parser/barg.js

const ELEMENTS_SEP = ";";
const ALIAS_SEP = ",";
const ATTR_SEP = ":";

let var_values = {};
let required_values = [];

let schema = {};
let alias_map = {};

let position = 0;
let level = 1;
let commands = ["root"];

function register_command(raw_entry) {
  const header = raw_entry.split(ELEMENTS_SEP).slice(1);
  const aliases = header.shift().split(ALIAS_SEP);
  const name = aliases[0];
  const help = header.shift();

  // Schema
  schema[ref(name, "type")] = "command";
  schema[ref(name, "help")] = help;

  // Alias
  for (const alias of aliases) {
    alias_map[ref(`unk::${alias}`)] = ref(name);
  }

  // Control
  commands.push(name);
  level += 1;
  position = 0;
}

function end_command() {
  level -= 1;
  commands.pop();
}

function register_argument(raw_entry) {
  const elements = raw_entry.split(ELEMENTS_SEP).slice(1);
  let aliases = elements.shift().split(ALIAS_SEP);
  let name = aliases[0];
  const entry = {
    required: false,
    kind: "positional",
  };
  for (const element of elements) {
    const [attribute, attr_value] = element.split(ATTR_SEP);

    if (attribute === "required") entry.required = true;
    else if (attribute === "repeatable") entry.repeatable = true;
    else if (attribute === "help") entry.help = attr_value;
    else if (attribute === "default") entry.default_value = attr_value;
    else if (attribute === "dest") entry.dest = attr_value;
    else if (attribute === "type") entry.kind = attr_value;

    // Defaults
    if (entry.dest === undefined) entry.dest = name;
    if (entry.value === undefined) entry.value = entry.default_value;
  }

  // Alias
  if (entry.kind === "positional") {
    name = String(position++);
    aliases = [`pos::${name}`];
  } else if (entry.kind === "rest") {
    aliases = ["__rest"];
  }

  for (const alias of aliases) {
    if (entry.kind === "option" || entry.kind === "flag")
      alias_map[ref(`narg::${alias}`)] = ref(name);
    else alias_map[ref(alias)] = ref(name);
  }

  // Schema
  schema[ref(name, "type")] = "argument";
  for (const [key, value] of Object.entries(entry)) {
    schema[ref(name, key)] = value;
  }
}

function generate_schema(spec) {
  for (const entry of spec) {
    const elements = entry.split(ELEMENTS_SEP);
    const type = elements.shift();

    switch (type) {
      case "command":
        register_command(entry);
        break;
      case "end":
        end_command();
        break;
      case "argument":
        register_argument(entry);
        break;
      default:
        throw new Error(`Invalid entry type: '${type}'`);
    }
  }

  position = 0;
  level = 1;
  commands = ["root"];
}

function parse_input(spec, input) {
  // rest
  var_values = {};
  required_values = [];
  position = 0;
  level = 1;
  commands = ["root"];
  schema = {};
  alias_map = {};

  // code
  generate_schema(spec);
  const tokens = tokenize(input);

  // log({ schema, alias_map });

  function next_token() {
    const tagged_token = tokens.shift();
    const [type, token] = tagged_token.split("::");
    return { original: tagged_token, type, token };
  }

  function next_value() {
    const tagged_token = next_token();
    if (tagged_token.type !== "unk") {
      throw new Error(`Expected option value, but got: ${tagged_token.token}`);
    }
    return tagged_token.token;
  }

  while (tokens.length > 0) {
    const {
      original: token,
      type: token_type,
      token: token_value,
    } = next_token();
    if (token_type === "rest") {
      var_values["__rest"] = token_value;
      continue;
    }

    let found = false;
    for (let i = commands.length; i >= 1; i--) {
      level = i;
      let entry_ref = alias_map[ref(token)];

      if (!entry_ref && level === commands.length && token_type === "unk") {
        entry_ref = alias_map[ref(`pos::${position++}`)];
      }

      if (!entry_ref) {
        continue;
      }

      const [_token_type, token_value] = token.split("::");
      const type = schema[join(entry_ref, "type")];
      if (type === "command") {
        commands.push(token_value);
        level += commands.length;
      } else if (type === "argument") {
        const kind = schema[join(entry_ref, "kind")];
        const dest = schema[join(entry_ref, "dest")];
        const value = schema[join(entry_ref, "value")];

        var_values[dest] = value; // default one?

        if (kind === "flag") var_values[dest] = true;
        else if (kind === "option") var_values[dest] = next_value();
        else if (kind === "positional") var_values[dest] = token_value;
        else if (kind === "rest") var_values[dest] = token_value;
      }

      found = true;
      break;
    }

    if (!found) {
      console.log(`(Skipping invalid argument: '${token_value}'`);
    }
  }

  log({ commands, var_values });
  return var_values;
}

function tokenize(input) {
  const raw_tokens = input.split(/\s+/);
  raw_tokens.shift(); // drop command

  const tokens = [];
  while (raw_tokens.length > 0) {
    let token = take_token(raw_tokens);
    let value;

    if (token === "--") {
      tokens.push(`rest::${take_all(raw_tokens).join(" ")}`);
      continue;
    }

    if (token.startsWith("--")) {
      [token, value] = token.slice(2).split("=");
      tokens.push(`narg::${token}`);
    } else if (token.startsWith("-")) {
      [token, value] = token.slice(1).split("=");
      tokens.push(...token.split("").map((t) => `narg::${t}`));
    } else {
      tokens.push(`unk::${token}`);
    }

    if (value) {
      tokens.push(`value::${value}`);
    }
  }

  return tokens;
}

function take_token(tokens) {
  return tokens.shift();
}

function take_all(tokens) {
  const all = [...tokens];
  tokens.length = 0;
  return all;
}

function ref(...rest) {
  return commands.slice(0, level).concat(rest).join(".");
}

function join(...rest) {
  return rest.filter((v) => !!v).join(".");
}

function log(text) {
  console.log(JSON.stringify(text, null, 2));
}
const SPEC = [
  "command;build;Build a dev container",
  "argument;from;type:option;map:from_name;help:Name of the base container",
  "argument;name;type:positional;required;help:Name of the container",
  "argument;image,i;type:option;required;map:image_name;help:Base image",
  "argument;include,I;type:option;repeatable;map:include_paths;help:Include paths",
  "argument;verbose,v;type:flag;repeatable;default:0;help:Increase verbosity (-v, -vv, ...)",
  "argument;quiet,q;type:flag;default:false;help:Suppress all output",
  "argument;cmd;type:rest;map:cmd_rest;help:Command and args to run inside the container",
  "argument;name;dest:name_opt;type:option;help:Building container name",
  "command;container;Container building",
  "argument;dev;type:flag;help:Is dev or not",
  "argument;name;required;help:Building container name",
  "end",
  "argument;external;required;help:Name of the external container",
  "end",
  "command;stop;Stop a dev container",
  "argument;name;type:positional;required;help:Name of the container",
  "argument;kill,k;type:flag;default:false;help:Force kill the container",
  "end",
];

const INPUTS = [
  "dev build --from base-dev --image node:18 --include src --include test -v -v -q mycontainer -- npm run start",
  "dev build container --dev --name webapp externalContainer",
  "dev stop mycontainer --kill",
  "dev build --from alpine --image node:20 mybox -- echo hi",
];

INPUTS.forEach((input) => {
  console.log("\n\n------------------------\n");
  console.log("> ", input);
  parse_input(SPEC, input);
});