barg-parser/barg.js

/**
 * TODO:
 * - Add logic for repeatable attribute
 */

function log(text) {
  console.log(JSON.stringify(text, null, 2));
}

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

function takeOne(list) {
  return list.shift();
}

function takeAll(list) {
  const all = list.slice();
  list.length = 0;
  return all;
}

function map(key, cases, options = { error: true }) {
  const DEFAULT = "_";
  const hasKey = key != null && cases.hasOwnProperty(key);
  const hasDefault = cases.hasOwnProperty(DEFAULT);

  if (!hasKey && !hasDefault) {
    if (options.error) {
      throw new Error(`Invalid map key "${key}". Valid keys: ${Object.keys(cases).join(", ")}`);
    }
    return null;
  }

  return cases[hasKey ? key : DEFAULT];
}

function tokenize(input) {
  const args = input.trim().split(/\s+/);
  const root = args.shift();
  const tokens = [`root::${root}`];

  while (args.length) {
    const token = takeOne(args);

    // Rest
    if (token === "--") {
      tokens.push(`rest::${takeAll(args).join(" ")}`);
      break;
    }

    // Named Argument + Value: Option or Flag (long variant)
    if (token.startsWith("--")) {
      const [key, value] = token.slice(2).split("=");
      tokens.push(`narg::${key}`);
      if (value) tokens.push(`value::${value}`);
      continue;
    }

    // Named Argument + Value: Option or Flag (short variant)
    if (token.startsWith("-")) {
      const [flags, value] = token.slice(1).split("=");
      tokens.push(...flags.split("").map((f) => `narg::${f}`));
      if (value) tokens.push(`value::${value}`);
      continue;
    }

    // Unknown: Command, Positional or Value
    tokens.push(`unk::${token}`);
  }

  return tokens;
}

function parseInput(spec, input) {
  const tokens = tokenize(input);
  const s = {};
  const a = {};

  let _id = 100;
  let level = -1;
  let pos = [];
  let cmds = [];

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

      map(type, {
        command: () => {
          const id = String(_id++);
          const aliases = elements.shift().split(",");
          const help = elements.shift();

          // Schema
          s[join(id, "entryType")] = "command";
          s[join(id, "name")] = aliases[0];
          s[join(id, "help")] = help;
          s[join(id, "args")] = "";

          // Alias
          if (cmds.length === 0) {
            a[`cmd::root`] = id;
          } else {
            aliases.forEach((alias) => (a[join(cmds.at(-1), `cmd::${alias}`)] = id));
          }

          // Control
          level += 1;
          cmds.push(id);
          pos.push(0);
        },
        end: () => {
          level -= 1;
          cmds.pop();
          pos.pop();
        },
        argument: () => {
          const id = String(_id++);
          const aliases = elements.shift().split(",");
          const name = aliases[0];

          // Attributes
          const entry = { name, dest: name, required: false, type: "positional" };
          for (const element of elements) {
            const [key, value = true] = element.split(":");
            entry[key === "default" ? "value" : key] = value;
          }

          // Schema
          s[join(id, "entryType")] = "argument";
          Object.entries(entry).forEach(([key, value]) => {
            s[join(id, key)] = value;
          });

          // Register to command
          const cmdArgs = join(cmds.at(-1), "args");
          s[cmdArgs] += s[cmdArgs] ? `,${id}` : id;

          // Alias
          map(entry.type, {
            positional: () => [`pos::${pos[level]++}`],
            rest: () => ["rest"],
            option: () => aliases.map((a) => `narg::${a}`),
            flag: () => aliases.map((a) => `narg::${a}`),
          })().forEach((alias) => (a[join(cmds.at(-1), alias)] = id));
        },
        _: () => {
          throw new Error(`Invalid entry type: "${type}"`);
        },
      })();
    }

    level = 0;
    pos = [];
    cmds = [];
  }

  generateSchema();
  // log({ s, a });

  while (tokens.length > 0) {
    const taggedToken = takeOne(tokens);
    const [tokenTag, token] = taggedToken.split("::");

    // Bubble up arguments -> Loop over all command levels starting by the latest
    let found = false;
    for (level = Math.max(0, cmds.length - 1); level >= 0; level--) {
      const entryId = map(tokenTag, {
        root: () => a["cmd::root"],
        rest: () => a[join(cmds[level], "rest")],
        narg: () => a[join(cmds[level], taggedToken)],
        unk: () => {
          // check: Command
          let id = a[join(cmds[level], `cmd::${token}`)];

          // check: Positionl. Valid only on last command level
          if (!id && level === pos.length - 1) {
            id = a[join(cmds[level], `pos::${pos[level]}`)];
            if (id) pos[level]++;
          }

          return id;
        },
      })();

      // Try with parent command
      if (!entryId) continue;

      // Add
      const entryType = s[join(entryId, "entryType")];
      map(entryType, {
        command: () => {
          cmds.push(entryId);
          pos.push(0);
          if (tokenTag === "root") {
            s[join(entryId, "name")] = token;
          }
        },
        argument: () => {
          const attrType = s[join(entryId, "type")];
          const value = map(attrType, {
            rest: () => token,
            positional: () => token,
            flag: () => true,
            option: () => {
              const nTaggedToken = tokens[0];
              if (!nTaggedToken) {
                throw new Error(`No value provided for option argument: "${token}"`);
              }
              const [nTokenTag, nToken] = nTaggedToken.split("::");
              if (nTokenTag !== "value" && nTokenTag !== "unk") {
                throw new Error(
                  `Expected option argument, but got: "${nToken}" (${nTokenTag}). Skipping...`,
                );
              }
              tokens.shift();
              return nToken;
            },
          })();
          s[join(entryId, "value")] = value;
        },
      })();

      found = true;
      break;
    }

    if (!found) {
      console.log(`Invalid argument: "${token}" (${tokenTag}). Skipping...`);
    }
  }

  // Set values and check required
  const commands = [];
  const values = {};
  for (const cmdId of cmds) {
    let cmdName = s[join(cmdId, "name")];
    let cmdArgs = s[join(cmdId, "args")];
    if (!cmdArgs) continue;

    for (const argId of cmdArgs.split(",")) {
      const name = s[join(argId, "name")];
      const dest = s[join(argId, "dest")];
      const value = s[join(argId, "value")];
      const required = s[join(argId, "required")];

      if (value == null && required) {
        throw new Error(`Argument "${name}" is required in command "${cmdName}"`);
      }

      if (values[dest] != null) {
        values[`${cmdName}_${dest}`] = value;
      } else {
        values[dest] = value;
      }
    }
    commands.push(cmdName);
  }

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

function parseInputWrap(spec, input) {
  try {
    parseInput(spec, input);
  } catch (error) {
    console.error(`Error: ${error.message}`);
  }
}

const SPEC = [
  "command;barg;Barg - Bash Argument Parser",
  "argument;global;type:flag",
  "command;build;Build a dev container",
  "argument;from;type:option;dest:fromName;help:Name of the base container",
  "argument;name;type:positional;required;help:Name of the container",
  "argument;nametwo;help:Name of the container",
  "argument;image,i;type:option;required;dest:imageName;help:Base image",
  "argument;include,I;type:option;repeatable;dest:includePaths;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;help:Command and args to run inside the container",
  "argument;name;dest:nameOpt;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",
  "argument;cmd;type:rest;dest:cmdRest;help:Command and args to run inside the container",
  "end",
  "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",
  "end",
];

const INPUTS = [
  "dev build -i myimage buildtwo --from base-dev --image node:18 --include src --include test -v -v -q mycontainer -- npm run start",
  "dev build buildname container -i myimage --dev --name webapp externalContainer",
  "dev --global build --image debian mybox container --dev --name webapp externalContainer -- echo hi",
  "dev stop mycontainer --kill",
  "dev stop mycontainer --kill -- not specified one",
  "dev build --from alpine --image node:20 mybox -- echo hi",
  "dev build --aaaaa --from alpine --image node:20 --bbbbb orb mybox ccccc -- echo hi",
];

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