refactor(DocLink): allow absolute path and src

Author: std-microblock

src/components/DocLink.astro

@@ -2,23 +2,23 @@
 import { getLinkToKey } from "../lib/doc-index";
 
 interface Props {
-  dest: string;
+  src: string;
 }
 
-const { dest } = Astro.props;
-const rawLink = await getLinkToKey(dest);
+const { src } = Astro.props;
+const rawLink = await getLinkToKey(src);
 
 const missing = rawLink === undefined;
 const link = rawLink ?? "";
 ---
 
 {
   missing ? (
-    <span class="doc-link missing" title={`${dest} (missing)`}>
+    <span class="doc-link missing" title={`${src} (missing)`}>
       <slot />
     </span>
   ) : (
-    <a class="doc-link" href={link} title={dest}>
+    <a class="doc-link" href={link} title={src}>
       <slot />
     </a>
   )

src/content/docs/cpp/language/basic_concepts.mdx

@@ -12,7 +12,7 @@ import { Revision } from "@components/revision";
 
 This section provides definitions for the specific terminology and the concepts used when describing the C++ programming language.
 
-A C++ program is a sequence of text files (typically header and source files) that contain <Missing>declarations</Missing>. They undergo <Missing>translation</Missing> to become an executable program, which is executed when the C++ implementation calls its <DocLink dest="cpp.lang.main">main function</DocLink>.
+A C++ program is a sequence of text files (typically header and source files) that contain <Missing>declarations</Missing>. They undergo <Missing>translation</Missing> to become an executable program, which is executed when the C++ implementation calls its <DocLink src="/cpp/language/main_function">main function</DocLink>.
 
 Certain words in a C++ program have special meaning, and these are known as <Missing>keywords</Missing>. Others can be used as <Missing>identifiers</Missing>. <Missing>Comments</Missing> are ignored during translation. C++ programs also contain <Missing>literals</Missing>, the values of characters inside them are determined by <Missing>character sets and encodings</Missing>. Certain characters in the program have to be represented with <Missing>escape sequences</Missing>.
 

src/content/docs/development/guide/doc-everything.mdx

@@ -290,18 +290,24 @@ cppdoc:
   While a page can have multiple doc keys, each unique doc key can only be associated to at most one page.
 </Aside>
 
-The `DocLink` component allows you to render an inline link to the page associated with the specified doc key.
+The `DocLink` component allows you to render an inline link to the page associated with the specified doc key. You can also specify the destination page by its absolute path.
 
 ```mdx
 import DocLink from "@components/DocLink.astro";
 
 Check out
-<DocLink key="cpp.library.utilities.move">this page</DocLink>
+<DocLink src="cpp.library.utilities.move">this page</DocLink>
+for more information about `std::move`.
+
+Check out
+<DocLink src="/cpp/library/utilities/move">this page</DocLink>
 for more information about `std::move`.
 ```
 
 <Card title="Preview">
-  Check out <DocLink key="cpp.library.utilities.move">this page</DocLink> for detailed information about `std::move`.
+  Check out <DocLink src="cpp.library.utilities.move">this page</DocLink> for detailed information about `std::move`.
+
+  Check out <DocLink src="/cpp/library/utilities/move">this page</DocLink> for more information about `std::move`.
 </Card>
 
 <Aside type="tip">

src/lib/doc-index.ts

@@ -57,8 +57,8 @@ async function getOrBuildKeyIndex(): Promise<Map<string, string>> {
  */
 export async function getLinkToKey(key: string): Promise<string | undefined> {
   const index = await getOrBuildKeyIndex();
-  if (key.startsWith("/")) {
-    if (Object.values(index).some(slug => `/${slug}/` === key || `/${slug}` === key))
+  if (key?.startsWith("/")) {
+    if (index.values().some(slug => `/${slug}/` === key || `/${slug}` === key))
       return key;
     else
       return undefined;