update odlux and featureaggregator

v2 update odlux and featureaggregator bundles

Issue-ID: SDNC-1008
Signed-off-by: herbert <herbert.eiselt@highstreet-technologies.com>
Change-Id: I0018d7bfa3a0e6896c1b210b539a574af9808e22
Signed-off-by: herbert <herbert.eiselt@highstreet-technologies.com>

1 files changed, 1099 insertions, 0 deletions

diff --git a/sdnr/wt/odlux/apps/configurationApp/src/yang/yangParser.ts b/sdnr/wt/odlux/apps/configurationApp/src/yang/yangParser.ts
new file mode 100644
index 000000000..c7ab5e4a3
--- /dev/null
+++ b/sdnr/wt/odlux/apps/configurationApp/src/yang/yangParser.ts
@@ -0,0 +1,1099 @@
+
+import { Token, Statement, Module, Identity } from "../models/yang";
+import { ViewSpecification, ViewElement, isViewElementObjectOrList, ViewElementBase, isViewElementReference } from "../models/uiModels";
+import { yangService } from "../services/yangService";
+
+export const splitVPath = (vPath: string, vPathParser: RegExp): RegExpMatchArray[] => {
+  const pathParts: RegExpMatchArray[] = [];
+  let partMatch: RegExpExecArray | null;
+  if (vPath) do {
+    partMatch = vPathParser.exec(vPath);
+    if (partMatch) {
+      pathParts.push(partMatch);
+    }
+  } while (partMatch)
+  return pathParts;
+}
+
+class YangLexer {
+
+  private pos: number = 0;
+  private buf: string = "";
+
+  constructor(input: string) {
+    this.pos = 0;
+    this.buf = input;
+  }
+
+  private _optable: { [key: string]: string } = {
+    ';': 'SEMI',
+    '{': 'L_BRACE',
+    '}': 'R_BRACE',
+  };
+
+  private _isNewline(char: string): boolean {
+    return char === '\r' || char === '\n';
+  }
+
+  private _isWhitespace(char: string): boolean {
+    return char === ' ' || char === '\t' || this._isNewline(char);
+  }
+
+  private _isDigit(char: string): boolean {
+    return char >= '0' && char <= '9';
+  }
+
+  private _isAlpha(char: string): boolean {
+    return (char >= 'a' && char <= 'z') ||
+      (char >= 'A' && char <= 'Z')
+  }
+
+  private _isAlphanum(char: string): boolean {
+    return this._isAlpha(char) || this._isDigit(char) ||
+      char === '_' || char === '-' || char === '.';
+  }
+
+  private _skipNontokens() {
+    while (this.pos < this.buf.length) {
+      const char = this.buf.charAt(this.pos);
+      if (this._isWhitespace(char)) {
+        this.pos++;
+      } else {
+        break;
+      }
+    }
+  }
+
+  private _processString(terminator: string | null): Token {
+    // this.pos points at the opening quote. Find the ending quote.
+    let end_index = this.pos + 1;
+    while (end_index < this.buf.length) {
+      const char = this.buf.charAt(end_index);
+      if (char === "\\") {
+        end_index += 2;
+        continue;
+      };
+      if (terminator === null && (this._isWhitespace(char) || this._optable[char] !== undefined) || char === terminator) {
+        break;
+      }
+      end_index++;
+    }
+
+    if (end_index >= this.buf.length) {
+      throw Error('Unterminated quote at ' + this.pos);
+    } else {
+      const start = this.pos + (terminator ? 1 : 0);
+      const end = end_index;
+      const tok = {
+        name: 'STRING',
+        value: this.buf.substring(start, end),
+        start,
+        end
+      };
+      this.pos = terminator ? end + 1 : end;
+      return tok;
+    }
+  }
+
+  private _processIdentifier(): Token {
+    let endpos = this.pos + 1;
+    while (endpos < this.buf.length &&
+      this._isAlphanum(this.buf.charAt(endpos))) {
+      endpos++;
+    }
+
+    const tok = {
+      name: 'IDENTIFIER',
+      value: this.buf.substring(this.pos, endpos),
+      start: this.pos,
+      end: endpos
+    };
+    this.pos = endpos;
+    return tok;
+  }
+
+  private _processNumber(): Token {
+    let endpos = this.pos + 1;
+    while (endpos < this.buf.length &&
+      this._isDigit(this.buf.charAt(endpos))) {
+      endpos++;
+    }
+
+    const tok = {
+      name: 'NUMBER',
+      value: this.buf.substring(this.pos, endpos),
+      start: this.pos,
+      end: endpos
+    };
+    this.pos = endpos;
+    return tok;
+  }
+
+  private _processLineComment() {
+    var endpos = this.pos + 2;
+    // Skip until the end of the line
+    while (endpos < this.buf.length && !this._isNewline(this.buf.charAt(endpos))) {
+      endpos++;
+    }
+    this.pos = endpos + 1;
+  }
+
+  private _processBlockComment() {
+    var endpos = this.pos + 2;
+    // Skip until the end of the line
+    while (endpos < this.buf.length && !((this.buf.charAt(endpos) === "/" && this.buf.charAt(endpos - 1) === "*"))) {
+      endpos++;
+    }
+    this.pos = endpos + 1;
+  }
+
+  public tokenize(): Token[] {
+    const result: Token[] = [];
+    this._skipNontokens();
+    while (this.pos < this.buf.length) {
+
+      const char = this.buf.charAt(this.pos);
+      const op = this._optable[char];
+
+      if (op !== undefined) {
+        result.push({ name: op, value: char, start: this.pos, end: ++this.pos });
+      } else if (this._isAlpha(char)) {
+        result.push(this._processIdentifier());
+        this._skipNontokens();
+        const peekChar = this.buf.charAt(this.pos);
+        if (this._optable[peekChar] === undefined) {
+          result.push((peekChar !== "'" && peekChar !== '"')
+            ? this._processString(null)
+            : this._processString(peekChar));
+        }
+      } else if (char === '/' && this.buf.charAt(this.pos + 1) === "/") {
+        this._processLineComment();
+      } else if (char === '/' && this.buf.charAt(this.pos + 1) === "*") {
+        this._processBlockComment();
+      } else {
+        throw Error('Token error at ' + this.pos + " " + this.buf[this.pos]);
+      }
+      this._skipNontokens();
+    }
+    return result;
+  }
+
+  public tokenize2(): Statement {
+    let stack: Statement[] = [{ key: "ROOT", sub: [] }];
+    let current: Statement | null = null;
+
+    this._skipNontokens();
+    while (this.pos < this.buf.length) {
+
+      const char = this.buf.charAt(this.pos);
+      const op = this._optable[char];
+
+      if (op !== undefined) {
+        if (op === "L_BRACE") {
+          current && stack.unshift(current);
+          current = null;
+        } else if (op === "R_BRACE") {
+          current = stack.shift() || null;
+        }
+        this.pos++;
+      } else if (this._isAlpha(char)) {
+        const key = this._processIdentifier().value;
+        this._skipNontokens();
+        let peekChar = this.buf.charAt(this.pos);
+        let arg = undefined;
+        if (this._optable[peekChar] === undefined) {
+          arg = (peekChar === '"' || peekChar === "'")
+            ? this._processString(peekChar).value
+            : this._processString(null).value;
+        }
+        do {
+          this._skipNontokens();
+          peekChar = this.buf.charAt(this.pos);
+          if (peekChar !== "+") break;
+          this.pos++;
+          this._skipNontokens();
+          peekChar = this.buf.charAt(this.pos);
+          arg += (peekChar === '"' || peekChar === "'")
+            ? this._processString(peekChar).value
+            : this._processString(null).value;
+        } while (true);
+        current = { key, arg, sub: [] };
+        stack[0].sub!.push(current);
+      } else if (char === '/' && this.buf.charAt(this.pos + 1) === "/") {
+        this._processLineComment();
+      } else if (char === '/' && this.buf.charAt(this.pos + 1) === "*") {
+        this._processBlockComment();
+      } else {
+        throw Error('Token error at ' + this.pos + " " + this.buf.slice(this.pos - 10, this.pos + 10));
+      }
+      this._skipNontokens();
+    }
+    if (stack[0].key !== "ROOT" || !stack[0].sub![0]) {
+      throw new Error("Internal Perser Error");
+    }
+    return stack[0].sub![0];
+  }
+}
+
+export class YangParser {
+  private _groupingsToResolve: (() => void)[] = [];
+  private _identityToResolve: (() => void)[] = [];
+
+  private _modules: { [name: string]: Module } = {};
+  private _views: ViewSpecification[] = [{
+    id: "0",
+    name: "root",
+    language: "en-US",
+    canEdit: false,
+    parentView: "0",
+    title: "root",
+    elements: {},
+   }];
+
+  constructor() {
+
+  }
+
+  public get modules() {
+    return this._modules;
+  }
+
+  public get views() {
+    return this._views;
+  }
+
+  public async addCapability(capability: string, version?: string) {
+    // do not add twice
+    if (this._modules[capability]) {
+      return;
+    }
+
+    const data = await yangService.getCapability(capability, version);
+    if (!data) {
+      throw new Error(`Could not load yang file for ${capability}.`);
+    }
+
+    const rootStatement = new YangLexer(data).tokenize2();
+
+    if (rootStatement.key !== "module") {
+      throw new Error(`Root element of ${capability} is not a module.`);
+    }
+    if (rootStatement.arg !== capability) {
+      throw new Error(`Root element capability ${rootStatement.arg} does not requested ${capability}.`);
+    }
+
+    const module = this._modules[capability] = {
+      name: rootStatement.arg,
+      revisions: {},
+      imports: {},
+      features: {},
+      identities: {},
+      augments: {},
+      groupings: {},
+      typedefs: {},
+      views: {},
+      elements: {}
+    };
+
+    await this.handleModule(module, rootStatement, capability);
+  }
+
+  private async handleModule(module: Module, rootStatement: Statement, capability: string) {
+
+    // extract namespace && prefix
+    module.namespace = this.extractValue(rootStatement, "namespace");
+    module.prefix = this.extractValue(rootStatement, "prefix");
+    if (module.prefix) {
+      module.imports[module.prefix] = capability;
+    }
+
+    // extract revisions
+    const revisions = this.extractNodes(rootStatement, "revision");
+    module.revisions = {
+      ...module.revisions,
+      ...revisions.reduce<{ [version: string]: { }}>((acc, version) => {
+        if (!version.arg) {
+          throw new Error(`Module [${module.name}] has a version w/o version number.`);
+        }
+        const description = this.extractValue(version, "description");
+        const reference = this.extractValue(version,"reference");
+        acc[version.arg] = {
+          description,
+          reference,
+        };
+        return acc;
+      }, {})
+    };
+
+    // extract features
+    const features = this.extractNodes(rootStatement, "feature");
+    module.features = {
+      ...module.features,
+      ...features.reduce<{ [version: string]: {} }>((acc, feature) => {
+        if (!feature.arg) {
+          throw new Error(`Module [${module.name}] has a feature w/o name.`);
+        }
+        const description = this.extractValue(feature, "description");
+        acc[feature.arg] = {
+          description,
+        };
+        return acc;
+      }, {})
+    };
+
+    // extract imports
+    const imports = this.extractNodes(rootStatement, "import");
+    module.imports = {
+      ...module.imports,
+      ...imports.reduce < { [key: string]: string }>((acc, imp) => {
+        const prefix = imp.sub && imp.sub.filter(s => s.key === "prefix");
+        if (!imp.arg) {
+           throw new Error(`Module [${module.name}] has an import with neither name nor prefix.`);
+        }
+        acc[prefix && prefix.length === 1 && prefix[0].arg || imp.arg] = imp.arg;
+        return acc;
+      }, {})
+    };
+
+    // import all required files
+    if (imports) for (let ind = 0; ind < imports.length; ++ind) {
+      await this.addCapability(imports[ind].arg!);
+    }
+
+    this.extractTypeDefinitions(rootStatement, module, "");
+
+    this.extractIdentites(rootStatement, 0, module, "");
+
+    const groupings = this.extractGroupings(rootStatement, 0, module, "");
+    this._views.push(...groupings);
+
+    const augments = this.extractAugments(rootStatement, 0, module, "");
+    this._views.push(...augments);
+
+    // the default for config on module level is config = true;
+    const [currentView, subViews] = this.extractSubViews(rootStatement, 0, module, "");
+    this._views.push(currentView, ...subViews);
+
+    // create the root elements for this module
+    module.elements = currentView.elements;
+    Object.keys(module.elements).forEach(key => {
+      const viewElement = module.elements[key];
+      if (!isViewElementObjectOrList(viewElement)) {
+        throw new Error(`Module: [${module}]. Only List or Object allowed on root level.`);
+      }
+      const viewIdIndex = Number(viewElement.viewId);
+      module.views[key] = this._views[viewIdIndex];
+      this._views[0].elements[key] = module.elements[key];
+    });
+    return module;
+  }
+
+  public postProcess() {
+    // process all groupings
+    // execute all post processes like resolving in propper order
+    this._groupingsToResolve.forEach(cb => {
+      try { cb(); } catch (error) {
+        console.warn(`Error resolving: [${error.message}]`);
+      }
+    });
+
+    // process all augmentations
+    Object.keys(this.modules).forEach(modKey => {
+      const module = this.modules[modKey];
+      Object.keys(module.augments).forEach(augKey => {
+        const augments = module.augments[augKey];
+        const viewSpec = this.resolveView(augKey);
+        if (!viewSpec) console.warn(`Could not find view to augment [${augKey}] in [${module.name}].`);
+        if (augments && viewSpec) {
+          augments.forEach(augment => Object.keys(augment.elements).forEach(key => {
+            const elm = augment.elements[key];
+            viewSpec.elements[key] = {
+              ...augment.elements[key],
+              when: elm.when ? `(${augment.when}) and (${elm.when})` : augment.when,
+              ifFeature: elm.ifFeature ? `(${augment.ifFeature}) and (${elm.ifFeature})` : augment.ifFeature,
+            };
+          }));
+        }
+      });
+    });
+
+    // process Identities
+    const traverseIdentity = (identities : Identity[]) => {
+      const result: Identity[] = [];
+      for (let identity of identities) {
+        if (identity.children && identity.children.length > 0) {
+          result.push(...traverseIdentity(identity.children));
+        } else {
+          result.push(identity);
+        }
+      }
+      return result;
+    }
+
+
+    const baseIdentites: Identity[] = [];
+    Object.keys(this.modules).forEach(modKey => {
+      const module = this.modules[modKey];
+      Object.keys(module.identities).forEach(idKey => {
+        const identity = module.identities[idKey];
+        if (identity.base != null) {
+          const base = this.resolveIdentity(identity.base, module);
+          base.children?.push(identity);
+        } else {
+          baseIdentites.push(identity);
+        }
+      });
+    });
+    baseIdentites.forEach(identity => {
+      identity.values = identity.children && traverseIdentity(identity.children) || [];
+    });
+
+    this._identityToResolve.forEach(cb => {
+      try { cb(); } catch (error) {
+        console.warn(error.message);
+      }
+    });
+  };
+
+
+  private _nextId = 1;
+  private get nextId() {
+    return this._nextId++;
+  }
+
+  private extractNodes(statement: Statement, key: string): Statement[] {
+    return statement.sub && statement.sub.filter(s => s.key === key) || [];
+  }
+
+  private extractValue(statement: Statement, key: string): string | undefined;
+  private extractValue(statement: Statement, key: string, parser: RegExp): RegExpExecArray | undefined;
+  private extractValue(statement: Statement, key: string, parser?: RegExp): string | RegExpExecArray | undefined {
+    const typeNodes = this.extractNodes(statement, key);
+    const rawValue = typeNodes.length > 0 && typeNodes[0].arg || undefined;
+    return parser
+      ? rawValue && parser.exec(rawValue) || undefined
+      : rawValue;
+  }
+
+  private extractTypeDefinitions(statement: Statement, module: Module, currentPath: string): void {
+    const typedefs = this.extractNodes(statement, "typedef");
+    typedefs && typedefs.forEach(def => {
+      if (! def.arg) {
+        throw new Error(`Module: [${module.name}]. Found typefed without name.`);
+      }
+      module.typedefs[def.arg] = this.getViewElement(def, module, 0, currentPath, false);
+    });
+  }
+
+  /** Handles Goupings like named Container */
+  private extractGroupings(statement: Statement, parentId: number, module: Module, currentPath: string): ViewSpecification[] {
+    const subViews: ViewSpecification[] = [];
+    const groupings = this.extractNodes(statement, "grouping");
+    if (groupings && groupings.length > 0) {
+      subViews.push(...groupings.reduce<ViewSpecification[]>((acc, cur) => {
+        if (!cur.arg) {
+          throw new Error(`Module: [${module.name}][${currentPath}]. Found grouping without name.`);
+        }
+        const grouping = cur.arg;
+
+        // the default for config on module level is config = true;
+        const [currentView, subViews] = this.extractSubViews(cur, parentId, module, currentPath);
+        grouping && (module.groupings[grouping] = currentView);
+        acc.push(currentView, ...subViews);
+        return acc;
+      }, []));
+    }
+
+    return subViews;
+  }
+
+  /** Handles Augmants also like named Container */
+  private extractAugments(statement: Statement, parentId: number, module: Module, currentPath: string): ViewSpecification[] {
+    const subViews: ViewSpecification[] = [];
+    const augments = this.extractNodes(statement, "augment");
+    if (augments && augments.length > 0) {
+      subViews.push(...augments.reduce<ViewSpecification[]>((acc, cur) => {
+        if (!cur.arg) {
+          throw new Error(`Module: [${module.name}][${currentPath}]. Found augment without path.`);
+        }
+        const augment = this.resolveReferencePath(cur.arg, module);
+
+        // the default for config on module level is config = true;
+        const [currentView, subViews] = this.extractSubViews(cur, parentId, module, currentPath);
+        if (augment) {
+          module.augments[augment] = module.augments[augment] || [];
+          module.augments[augment].push(currentView);
+        }
+        acc.push(currentView, ...subViews);
+        return acc;
+      }, []));
+    }
+
+    return subViews;
+  }
+
+  /** Handles Identities  */
+  private extractIdentites(statement: Statement, parentId: number, module: Module, currentPath: string) {
+    const identities = this.extractNodes(statement, "identity");
+    module.identities = identities.reduce<{ [name: string]: Identity }>((acc, cur) => {
+      if (!cur.arg) {
+        throw new Error(`Module: [${module.name}][${currentPath}]. Found identiy without name.`);
+      }
+      acc[cur.arg] = {
+        id: `${module.name}:${cur.arg}`,
+        label: cur.arg,
+        base: this.extractValue(cur, "base"),
+        description: this.extractValue(cur, "description"),
+        reference: this.extractValue(cur, "reference"),
+        children: []
+      }
+      return acc;
+    }, {});
+  }
+
+  private extractSubViews(statement: Statement, parentId: number, module: Module, currentPath: string): [ViewSpecification, ViewSpecification[]] {
+    const subViews: ViewSpecification[] = [];
+    const currentId = this.nextId;
+    let elements: ViewElement[] = [];
+
+    const configValue = this.extractValue(statement, "config");
+    const config = configValue == null ? true : configValue.toLocaleLowerCase() !== "false";
+
+    // extract conditions
+    const ifFeature = this.extractValue(statement, "if-feature");
+    const whenCondition = this.extractValue(statement, "when");
+
+    // extract all container
+    const container = this.extractNodes(statement, "container");
+    if (container && container.length > 0) {
+      subViews.push(...container.reduce<ViewSpecification[]>((acc, cur) => {
+        if (!cur.arg) {
+          throw new Error(`Module: [${module.name}]. Found container without name.`);
+        }
+        const [currentView, subViews] = this.extractSubViews(cur, currentId, module, `${currentPath}/${module.name}:${cur.arg}`);
+        elements.push({
+          id: parentId === 0 ? `${module.name}:${cur.arg}` : cur.arg,
+          label: cur.arg,
+          uiType: "object",
+          viewId: currentView.id,
+          config: config
+        });
+        acc.push(currentView, ...subViews);
+        return acc;
+      }, []));
+    }
+
+    // process all lists
+    // a list is a list of containers with the leafs contained in the list
+    const lists = this.extractNodes(statement, "list");
+    if (lists && lists.length > 0) {
+      subViews.push(...lists.reduce<ViewSpecification[]>((acc, cur) => {
+        if (!cur.arg) {
+          throw new Error(`Module: [${module.name}]. Found list without name.`);
+        }
+        const key = this.extractValue(cur, "key") || undefined;
+        if (config && !key) {
+          throw new Error(`Module: [${module.name}]. Found configurable list without key.`);
+        }
+        const [currentView, subViews] = this.extractSubViews(cur, currentId, module, `${currentPath}/${module.name}:${cur.arg}`);
+        elements.push({
+          id: parentId === 0 ? `${module.name}:${cur.arg}` : cur.arg,
+          label: cur.arg,
+          isList: true,
+          uiType: "object",
+          viewId: currentView.id,
+          key: key,
+          config: config
+        });
+        acc.push(currentView, ...subViews);
+        return acc;
+      }, []));
+    }
+
+    // process all leaf-lists
+    // a leaf-list is a list of some type
+    const leafLists = this.extractNodes(statement, "leaf-list");
+    if (leafLists && leafLists.length > 0) {
+      elements.push(...leafLists.reduce<ViewElement[]>((acc, cur) => {
+        const element = this.getViewElement(cur, module, parentId, currentPath, true);
+        element && acc.push(element);
+        return acc;
+      }, []));
+    }
+
+    // process all leafs
+    // a leaf is mainly a property of an object
+    const leafs = this.extractNodes(statement, "leaf");
+    if (leafs && leafs.length > 0) {
+      elements.push(...leafs.reduce<ViewElement[]>((acc, cur) => {
+        const element = this.getViewElement(cur, module, parentId, currentPath, false);
+        element && acc.push(element);
+        return acc;
+      }, []));
+    }
+
+
+    const choiceStms = this.extractNodes(statement, "choice");
+    if (choiceStms && choiceStms.length > 0) {
+      for (let i = 0; i < choiceStms.length; ++i) {
+        const cases = this.extractNodes(choiceStms[i], "case");
+        console.warn(`Choice found ${choiceStms[i].arg}::${cases.map(c => c.arg).join(";")}`, choiceStms[i]);
+      }
+    }
+
+    const rpcs = this.extractNodes(statement, "rpc");
+    if (rpcs && rpcs.length > 0) {
+      // todo:
+    }
+
+    if (!statement.arg) {
+      throw new Error(`Module: [${module.name}]. Found statement without name.`);
+    }
+
+    const viewSpec: ViewSpecification = {
+      id: String(currentId),
+      parentView: String(parentId),
+      name: statement.arg,
+      title: statement.arg,
+      language: "en-us",
+      canEdit: false,
+      ifFeature: ifFeature,
+      when: whenCondition,
+      elements: elements.reduce<{ [name: string]: ViewElement }>((acc, cur) => {
+        acc[cur.id] = cur;
+        return acc;
+      }, {}),
+    };
+
+    // evaluate canEdit depending on all conditions
+    Object.defineProperty(viewSpec, "canEdit", {
+      get: () => {
+        return Object.keys(viewSpec.elements).some(key => {
+          const elm = viewSpec.elements[key];
+          return (!isViewElementObjectOrList(elm) && elm.config);
+        });
+      }
+    });
+
+    // merge in all uses references and resolve groupings
+    const usesRefs = this.extractNodes(statement, "uses");
+    if (usesRefs && usesRefs.length > 0) {
+
+      viewSpec.uses = (viewSpec.uses || []);
+      for (let i = 0; i < usesRefs.length; ++i) {
+        const groupingName = usesRefs[i].arg;
+        if (!groupingName) {
+          throw new Error(`Module: [${module.name}]. Found an uses statement without a grouping name.`);
+        }
+
+        viewSpec.uses.push(this.resolveReferencePath(groupingName, module));
+
+        this._groupingsToResolve.push(() => {
+          const groupingViewSpec = this.resolveGrouping(groupingName, module);
+          if (groupingViewSpec) {
+            Object.keys(groupingViewSpec.elements).forEach(key => {
+              const elm = groupingViewSpec.elements[key];
+              viewSpec.elements[key] = {
+                ...groupingViewSpec.elements[key],
+                when: elm.when ? `(${groupingViewSpec.when}) and (${elm.when})` : groupingViewSpec.when,
+                ifFeature: elm.ifFeature ? `(${groupingViewSpec.ifFeature}) and (${elm.ifFeature})` : groupingViewSpec.ifFeature,
+              };
+            });
+          }
+        });
+      }
+    }
+
+    return [viewSpec, subViews];
+  }
+
+  /** Extracts the UI View from the type in the cur statement. */
+  private getViewElement(cur: Statement, module: Module, parentId: number, currentPath: string, isList: boolean): ViewElement {
+
+    const type = this.extractValue(cur, "type");
+    const defaultVal = this.extractValue(cur, "default") || undefined;
+    const description = this.extractValue(cur, "description") || undefined;
+    const rangeMatch = this.extractValue(cur, "range", /^(\d+)\.\.(\d+)/) || undefined;
+
+    const configValue = this.extractValue(cur, "config");
+    const config = configValue == null ? true : configValue.toLocaleLowerCase() !== "false";
+
+    const mandatory = this.extractValue(cur, "mandatory") === "true" || false;
+
+    if (!cur.arg) {
+      throw new Error(`Module: [${module.name}]. Found element without name.`);
+    }
+
+    if (!type) {
+      throw new Error(`Module: [${module.name}].[${cur.arg}]. Found element without type.`);
+    }
+
+    const element: ViewElementBase = {
+      id: parentId === 0 ? `${module.name}:${cur.arg}`: cur.arg,
+      label: cur.arg,
+      config: config,
+      mandatory: mandatory,
+      isList: isList,
+      default: defaultVal,
+      description: description
+    };
+
+    if (type === "string") {
+      return ({
+        ...element,
+        uiType: "string",
+        pattern: this.extractNodes(this.extractNodes(cur, "type")[0]!, "pattern").map(p => p.arg!).filter(p => !!p),
+      });
+    } else if (type === "boolean") {
+      return ({
+        ...element,
+        uiType: "boolean"
+      });
+    } else if (type === "uint8") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +255,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "uint16") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +65535,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "uint32") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +4294967295,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "uint64") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +18446744073709551615,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "int8") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : -128,
+        max: rangeMatch ? Number(rangeMatch[1]) : +127,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "int16") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : -32768,
+        max: rangeMatch ? Number(rangeMatch[1]) : +32767,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "int32") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : -2147483648,
+        max: rangeMatch ? Number(rangeMatch[1]) : +2147483647,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "int64") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +18446744073709551615,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+      });
+    } else if (type === "decimal16") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +18446744073709551615,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+        fDigits: Number(this.extractValue(this.extractNodes(cur, "type")[0]!, "fraction-digits")) || -1
+      });
+    } else if (type === "decimal32") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +18446744073709551615,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+        fDigits: Number(this.extractValue(this.extractNodes(cur, "type")[0]!, "fraction-digits")) || -1
+      });
+    } else if (type === "decimal64") {
+      return ({
+        ...element,
+        uiType: "number",
+        min: rangeMatch ? Number(rangeMatch[0]) : 0,
+        max: rangeMatch ? Number(rangeMatch[1]) : +18446744073709551615,
+        units: this.extractValue(cur, "units") || undefined,
+        format: this.extractValue(cur, "format") || undefined,
+        fDigits: Number(this.extractValue(this.extractNodes(cur, "type")[0]!, "fraction-digits")) || -1
+      });
+    } else if (type === "enumeration") {
+      const typeNode = this.extractNodes(cur, "type")[0]!;
+      const enumNodes = this.extractNodes(typeNode, "enum");
+      return ({
+        ...element,
+        uiType: "selection",
+        options: enumNodes.reduce<{ key: string; value: string; description?: string }[]>((acc, enumNode) => {
+          if (!enumNode.arg) {
+            throw new Error(`Module: [${module.name}][${currentPath}][${cur.arg}]. Found option without name.`);
+          }
+          const ifClause = this.extractValue(enumNode, "if-feature");
+          const value = this.extractValue(enumNode, "value");
+          const enumOption = {
+            key: enumNode.arg,
+            value: value != null ? value : enumNode.arg,
+            description: this.extractValue(enumNode, "description") || undefined
+          };
+          // todo: ❗ handle the if clause ⚡
+          acc.push(enumOption);
+          return acc;
+        }, [])
+      });
+    } else if (type === "leafref") {
+      const typeNode = this.extractNodes(cur, "type")[0]!;
+      const vPath = this.extractValue(typeNode, "path");
+      if (!vPath) {
+        throw new Error(`Module: [${module.name}][${currentPath}][${cur.arg}]. Found leafref without path.`);
+      }
+      const refPath = this.resolveReferencePath(vPath, module);
+      const resolve = this.resolveReference.bind(this);
+      const res : ViewElement = {
+        ...element,
+        uiType: "reference",
+        referencePath: refPath,
+        ref(this: ViewElement, currentPath: string) {
+          const resolved = resolve(refPath, currentPath);
+          return resolved && {
+            ...resolved,
+            id: this.id,
+            label: this.label,
+            config: this.config,
+            mandatory: this.mandatory,
+            isList: this.isList,
+            default: this.default,
+            description: this.description,
+          } as ViewElement;
+        }
+      };
+      return res;
+    } else if (type === "identityref") {
+      const typeNode = this.extractNodes(cur, "type")[0]!;
+      const base = this.extractValue(typeNode, "base");
+      if (!base) {
+        throw new Error(`Module: [${module.name}][${currentPath}][${cur.arg}]. Found identityref without base.`);
+      }
+      const res: ViewElement = {
+        ...element,
+        uiType: "selection",
+        options: []
+      };
+      this._identityToResolve.push(() => {
+        const identity : Identity = this.resolveIdentity(base, module);
+        if (!identity) {
+          throw new Error(`Module: [${module.name}][${currentPath}][${cur.arg}]. Could not resolve identity [${base}].`);
+        }
+        if (!identity.values || identity.values.length === 0) {
+          throw new Error(`Identity: [${base}] has no values.`);
+        }
+        res.options = identity.values.map(val => ({
+          key: val.id,
+          value: val.id,
+          description: val.description
+        }));
+      });
+      return res ;
+    } else if (type === "empty") {
+      // todo: ❗ handle empty ⚡
+      /*  9.11.  The empty Built-In Type
+          The empty built-in type represents a leaf that does not have any
+          value, it conveys information by its presence or absence. */
+      console.warn(`found type: empty in [${module.name}][${currentPath}][${element.label}]`);
+      return {
+        ...element,
+        uiType: "string",
+      };
+    } else if (type === "union") {
+      // todo: ❗ handle union ⚡
+      /* 9.12.  The union Built-In Type */
+      console.warn(`found type: union in [${module.name}][${currentPath}][${element.label}]`);
+      return {
+        ...element,
+        uiType: "string",
+      };
+    } else if (type === "bits") {
+      const typeNode = this.extractNodes(cur, "type")[0]!;
+      const bitNodes = this.extractNodes(typeNode, "bit");
+      return {
+        ...element,
+        uiType: "bits",
+        flags: bitNodes.reduce<{[name: string]: number | undefined; }>((acc, bitNode) => {
+          if (!bitNode.arg) {
+            throw new Error(`Module: [${module.name}][${currentPath}][${cur.arg}]. Found bit without name.`);
+          }
+          const ifClause = this.extractValue(bitNode, "if-feature");
+          const pos = Number(this.extractValue(bitNode, "position"));
+          acc[bitNode.arg] = pos === pos ? pos : undefined;
+          return acc;
+        }, {})
+      };
+    } else if (type === "binary") {
+      const typeNode = this.extractNodes(cur, "type")[0]!;
+      const length = Number(this.extractValue(typeNode, "length"));
+      return {
+        ...element,
+        uiType: "binary",
+        length: length === length ? length : undefined
+      };
+    } else {
+      // not a build in type, have to resolve type
+      const typeRef = this.resolveType(type, module);
+      if (typeRef == null) console.error(new Error(`Could not resolve type ${type} in [${module.name}][${currentPath}].`));
+      return ({
+        ...typeRef,
+        ...element,
+        description: description
+      }) as ViewElement;
+    }
+  }
+
+  private resolveReferencePath(vPath: string, module: Module) {
+    const vPathParser = /(?:(?:([^\/\:]+):)?([^\/]+))/g // 1 = opt: namespace / 2 = property
+    return vPath.replace(vPathParser, (_, ns, property) => {
+      const nameSpace = ns && module.imports[ns] || module.name;
+      return `${nameSpace}:${property}`;
+    });
+  }
+
+
+  private resolveReference(vPath: string, currentPath: string) {
+    const vPathParser = /(?:(?:([^\/\[\]\:]+):)?([^\/\[\]]+)(\[[^\]]+\])?)/g // 1 = opt: namespace / 2 = property / 3 = opt: indexPath
+    let element : ViewElement | null = null;
+    let moduleName = "";
+
+    const vPathParts = splitVPath(vPath, vPathParser).map(p => ({ ns: p[1], property: p[2], ind: p[3] }));
+    const resultPathParts = !vPath.startsWith("/")
+      ? splitVPath(currentPath, vPathParser).map(p => ({ ns: p[1], property: p[2], ind: p[3] }))
+      : [];
+
+    for (let i = 0; i < vPathParts.length; ++i){
+      const vPathPart = vPathParts[i];
+      if (vPathPart.property === "..") {
+        resultPathParts.pop();
+      } else if (vPathPart.property !== ".") {
+        resultPathParts.push(vPathPart);
+      }
+    }
+
+    // resolve element by path
+    for (let j = 0; j < resultPathParts.length;++j){
+      const pathPart = resultPathParts[j];
+        if (j===0) {
+          moduleName = pathPart.ns;
+          const rootModule = this._modules[moduleName];
+          if (!rootModule) throw new Error("Could not resolve module [" + moduleName +"].\r\n" + vPath);
+          element = rootModule.elements[`${pathPart.ns}:${pathPart.property}`];
+        } else if (element && isViewElementObjectOrList(element)) {
+          const view: ViewSpecification = this._views[+element.viewId];
+          if (moduleName !== pathPart.ns) {
+            moduleName = pathPart.ns;
+            element = view.elements[`${moduleName}:${pathPart.property}`];
+          } else {
+            element = view.elements[pathPart.property] || view.elements[`${moduleName}:${pathPart.property}`];
+          }
+        } else {
+          throw new Error("Could not resolve reference.\r\n" + vPath);
+        }
+        if (!element) throw new Error("Could not resolve path [" + pathPart.property + "] in ["+ currentPath +"] \r\n" + vPath);
+      }
+
+    return element;
+  }
+
+  private resolveView(vPath: string) {
+    const vPathParser = /(?:(?:([^\/\[\]\:]+):)?([^\/\[\]]+)(\[[^\]]+\])?)/g // 1 = opt: namespace / 2 = property / 3 = opt: indexPath
+    let element: ViewElement | null = null;
+    let partMatch: RegExpExecArray | null;
+    let view: ViewSpecification | null = null;
+    let moduleName = "";
+    if (vPath) do {
+      partMatch = vPathParser.exec(vPath);
+      if (partMatch) {
+        if (element === null) {
+          moduleName = partMatch[1]!;
+          const rootModule = this._modules[moduleName];
+          if (!rootModule) return null;
+          element = rootModule.elements[`${moduleName}:${partMatch[2]!}`];
+        } else if (isViewElementObjectOrList(element)) {
+          view = this._views[+element.viewId];
+          if (moduleName !== partMatch[1]) {
+            moduleName = partMatch[1];
+            element = view.elements[`${moduleName}:${partMatch[2]}`];
+          } else {
+            element = view.elements[partMatch[2]];
+          }
+        } else {
+          return null;
+        }
+        if (!element) return null;
+      }
+    } while (partMatch)
+    return element && isViewElementObjectOrList(element) && this._views[+element.viewId] || null;
+  }
+
+  private resolveType(type: string, module: Module) {
+    const collonInd = type.indexOf(":");
+    const preFix = collonInd > -1 ? type.slice(0, collonInd) : "";
+    const typeName = collonInd > -1 ? type.slice(collonInd + 1) : type;
+
+    const res = preFix
+      ? this._modules[module.imports[preFix]].typedefs[typeName]
+      : module.typedefs[typeName];
+    return res;
+  }
+
+  private resolveGrouping(grouping: string, module: Module) {
+    const collonInd = grouping.indexOf(":");
+    const preFix = collonInd > -1 ? grouping.slice(0, collonInd) : "";
+    const groupingName = collonInd > -1 ? grouping.slice(collonInd + 1) : grouping;
+
+    return preFix
+      ? this._modules[module.imports[preFix]].groupings[groupingName]
+      : module.groupings[groupingName];
+
+  }
+
+  private resolveIdentity(identity: string, module: Module) {
+    const collonInd = identity.indexOf(":");
+    const preFix = collonInd > -1 ? identity.slice(0, collonInd) : "";
+    const identityName = collonInd > -1 ? identity.slice(collonInd + 1) : identity;
+
+    return preFix
+      ? this._modules[module.imports[preFix]].identities[identityName]
+      : module.identities[identityName];
+
+  }
+}
\ No newline at end of file