feat(parser): create common directory for langium parsers

packages/parser/src/language/common/common.langium

@@ -0,0 +1,14 @@
+fragment TitleAndAccessibilities:
+  ((accDescr=ACC_DESCR | accTitle=ACC_TITLE | title=TITLE) NEWLINE+)+
+;
+
+terminal NEWLINE: /\r?\n/;
+terminal ACC_DESCR: /accDescr(?:[\t ]*:[\t ]*[^\n\r]*?(?=%%)|\s*{[^}]*})|accDescr(?:[\t ]*:[\t ]*[^\n\r]*|\s*{[^}]*})/;
+terminal ACC_TITLE: /accTitle[\t ]*:[\t ]*[^\n\r]*?(?=%%)|accTitle[\t ]*:[\t ]*[^\n\r]*/;
+terminal TITLE: /title(?:[\t ]+[^\n\r]*?|)(?=%%)|title(?:[\t ]+[^\n\r]*|)/;
+
+hidden terminal WHITESPACE: /[\t ]+/;
+// TODO: add YAML_COMMENT hidden rule without interfere actual grammar
+hidden terminal YAML: /---[\t ]*\r?\n[\S\s]*?---[\t ]*(?!.)/;
+hidden terminal DIRECTIVE: /[\t ]*%%{[\S\s]*?}%%\s*/;
+hidden terminal SINGLE_LINE_COMMENT: /[\t ]*%%[^\n\r]*/;

packages/parser/src/language/common/commonLexer.ts

@@ -0,0 +1,8 @@
+import type { LexerResult } from 'langium';
+import { DefaultLexer } from 'langium';
+
+export class CommonLexer extends DefaultLexer {
+  public override tokenize(text: string): LexerResult {
+    return super.tokenize(text + '\n');
+  }
+}

packages/parser/src/language/common/commonMatcher.ts

@@ -0,0 +1,14 @@
+/**
+ * Matches single and multiline accessible description
+ */
+export const accessibilityDescrRegex = /accDescr(?:[\t ]*:[\t ]*([^\n\r]*)|\s*{([^}]*)})/;
+
+/**
+ * Matches single line accessible title
+ */
+export const accessibilityTitleRegex = /accTitle[\t ]*:[\t ]*([^\n\r]*)/;
+
+/**
+ * Matches a single line title
+ */
+export const titleRegex = /title([\t ]+([^\n\r]*)|)/;

packages/parser/src/language/common/commonValueConverters.ts

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+import type { CstNode, GrammarAST, ValueType } from 'langium';
+import { DefaultValueConverter } from 'langium';
+
+import { accessibilityDescrRegex, accessibilityTitleRegex, titleRegex } from './commonMatcher.js';
+
+export class CommonValueConverter extends DefaultValueConverter {
+  protected override runConverter(
+    rule: GrammarAST.AbstractRule,
+    input: string,
+    cstNode: CstNode
+  ): ValueType {
+    const value: ValueType | undefined = CommonValueConverter.customRunConverter(
+      rule,
+      input,
+      cstNode
+    );
+    if (value === undefined) {
+      return super.runConverter(rule, input, cstNode);
+    } else {
+      return value;
+    }
+  }
+
+  /**
+   * A method contains convert logic to be used by class itself or `MermaidValueConverter`.
+   *
+   * @param rule - Parsed rule.
+   * @param input - Matched string.
+   * @param _cstNode - Node in the Concrete Syntax Tree (CST).
+   * @returns converted the value if it's common rule or `undefined` if it's not.
+   */
+  public static customRunConverter(
+    rule: GrammarAST.AbstractRule,
+    input: string,
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    _cstNode: CstNode
+  ): ValueType | undefined {
+    let regex: RegExp | undefined;
+    switch (rule.name) {
+      case 'ACC_DESCR': {
+        regex = new RegExp(accessibilityDescrRegex.source);
+        break;
+      }
+      case 'ACC_TITLE': {
+        regex = new RegExp(accessibilityTitleRegex.source);
+        break;
+      }
+      case 'TITLE': {
+        regex = new RegExp(titleRegex.source);
+        break;
+      }
+    }
+    if (regex === undefined) {
+      return undefined;
+    }
+    const match = regex.exec(input);
+    if (match === null) {
+      return undefined;
+    }
+    // single line title, accTitle, accDescr
+    if (match[1] !== undefined) {
+      return match[1].trim().replaceAll(/[\t ]{2,}/gm, ' ');
+    }
+    // multi line accDescr
+    if (match[2] !== undefined) {
+      return match[2]
+        .replaceAll(/^\s*/gm, '')
+        .replaceAll(/\s+$/gm, '')
+        .replaceAll(/[\t ]{2,}/gm, ' ')
+        .replaceAll(/[\n\r]{2,}/gm, '\n');
+    }
+    return undefined;
+  }
+}

packages/parser/src/language/common/index.ts

@@ -0,0 +1,2 @@
+export * from './commonLexer.js';
+export * from './commonValueConverters.js';