"Building a Desktop LLM App with cpp-httplib" (#2403)

docs-util/llm-app/extract_code.sh

@@ -0,0 +1,18 @@
+# Extract code block from a <details> section identified by data-file attribute.
+# Usage: extract_code <file> <data-file>
+# Example: extract_code ch01.md "main.cpp"
+extract_code() {
+  local file="$1" name="$2"
+  local output
+  output=$(awk -v name="$name" '
+    $0 ~ "data-file=\"" name "\"" { found=1; next }
+    found && /^```/ && !inside { inside=1; next }
+    inside && /^```/ { exit }
+    inside { print }
+  ' "$file")
+  if [ -z "$output" ]; then
+    echo "ERROR: extract_code: no match for data-file=\"$name\" in $file" >&2
+    return 1
+  fi
+  printf '%s\n' "$output"
+}