Merge branch 'main' into flow-blockchain

Author: bartolomej

collections/opensource-testing/index.md

@@ -43,7 +43,7 @@ items:
  - stefanjudis/grunt-photobox
  - nathanmarks/vrtest
  - reg-viz/reg-cli
- - segmentio/nightmare
+ - segment-boneyard/nightmare
  - reg-viz/reg-suit
  - xolvio/chimp
  - NimaSoroush/differencify

topics/cst/index.md

@@ -0,0 +1,9 @@
+---
+display_name: Concrete syntax tree
+short_description: A concrete syntax tree is a low level representation of the parsed source in the structure defined by a grammar description.
+topic: cst
+aliases: parse-tree, parsing-tree, derivation-tree
+wikipedia_url: https://en.wikipedia.org/wiki/Parse_tree
+related: ast
+---
+A concrete syntax tree is an ordered, rooted tree that represents the syntactic structure of a string according to some context-free grammar.

topics/nextra/index.md

@@ -0,0 +1,12 @@
+---
+display_name: Nextra
+short_description: Nextra is a simple, powerful and flexible site generation framework built with next.js.
+topic: nextra
+github_url: https://github.com/shuding/nextra
+url: https://nextra.site/
+related: nextjs, mdx, markdown
+logo: nextra.png
+---
+
+Nextra is a nextjs-based static site generation framework using markdown and MDX. 
+Nextra framework is specially built to create markdown-based documentation and portfolio blogs without coding using MDX and markdown.