How to use PROP_CODETREE_SUBLEXER to show sublexer code in codetree？

[main Alexey]

>then what's the use of ed.set_prop(PROP_CODETREE_SUBLEXER, Ture)？

It's use is for lexers without Pascal tree-helpers. for ex: PHP lexer with inclusion of JS and HTML blocks. or: HTML lexer with inclusion of JS block or CSS block.

I find that the "# sec5" in fenced-block will not be recognized as Markdown title

because this title is inside fenced block.

hat means if I define some additional lexer for Markdown，it will not be recognized in fenced-block？

yes. but you cannot 'define additional lexer for Markdown'. Markdown supports sublexers listed in the file
data/lexlib/aliases.ini

where can I find the description about how to make pascal tree-helper for cudatext？

See example codes in src:

treehelper_ini.pas
treehelper_markdown.pas
treehelper_mediawiki.pas
treehelper_rest.pas
treehelper_textile.pas
treehelper_wikidpad.pas

and
treehelpers_proc.pas - this 'registers' treehelpers.

that will be faster than python tree helper， right？

of course!

[SamC]

Any api method to directly add or delete a node in codetree？

[main Alexey]

Yes, API allows it.

- get handle of codetree: self.h_tree = app_proc(PROC_GET_CODETREE, '')
- handle event on_state, state==APPSTATE_CODETREE_AFTER_FILL
- add any treeview data using self.h_tree using tree_proc()

Example plugin: https://github.com/CudaText-addons/cuda_code_tree_x

[SamC]

Thanks, I wrote a python plugin "cuda_tree_markdown" to try to show some additional codetree node, but cuda raise the warning below：

NOTE: Plugin cuda_tree_markdown is in ignore-list, please remove it

How to active the user defined codetree for markdown？

[main Alexey]

'cuda_tree_markdown' is a fixed name of old (deleted) treehelper. modify it a little so it will be enabled.
https://github.com/CudaText-addons/cuda_tree_markdown