Function interpolateLuaString

client/space_lua/stdlib/space_lua.ts:56–107

(
  sf: LuaStackFrame,
  template: string,
  envAugmentation?: LuaTable,
)

 * @returns The interpolated string.
 */
export async function interpolateLuaString(
  sf: LuaStackFrame,
  template: string,
  envAugmentation?: LuaTable,
): Promise<string> {
  let result = "";
  let currentIndex = 0;

  while (true) {
    const startIndex = template.indexOf("${", currentIndex);
    if (startIndex === -1) {
      result += template.slice(currentIndex);
      break;
    }

    result += template.slice(currentIndex, startIndex);

    // Find matching closing brace by counting nesting
    let nestLevel = 1;
    let endIndex = startIndex + 2;
    while (nestLevel > 0 && endIndex < template.length) {
      if (template[endIndex] === "{") {
        nestLevel++;
      } else if (template[endIndex] === "}") {
        nestLevel--;
      }
      if (nestLevel > 0) {
        endIndex++;
      }
    }

    if (nestLevel > 0) {
      throw new LuaRuntimeError("Unclosed interpolation expression", sf);
    }

    const expr = template.slice(startIndex + 2, endIndex);
    try {
      const parsedExpr = parseExpressionString(expr);
      const env = createAugmentedEnv(sf, envAugmentation);
      // Do `luaToString` before `luaValueToJS` to preserve tagged float
      // formatting.
      const luaResult = singleResult(await evalExpression(parsedExpr, env, sf));
      result += await luaToString(luaResult);
    } catch (e: any) {
      throw new LuaRuntimeError(`Error evaluating "${expr}": ${e.message}`, sf);
    }

    currentIndex = endIndex + 1;
  }

  return result;
}

/**
 * Converts an optional Lua options table into a `PrintOptions` object,