wifi error for raspberry: brcmfmac: brcmf_set_channel: set chanspec 0x100e fail, reason -52

 

I couldn't connect to my raspberry pi for several days. Today I conducted a trouble shooting. 

At beginning, I think system is down due to flashcard broken but later I found raspyberry still has ipv4/ipv6 address from home router. I tried to ssh but not successful. I ping the server first, ping is Ok. Then I could ssh server successfully.

it seems i am not the only guy who has this issue, see 

https://forums.raspberrypi.com/viewtopic.php?t=367466

https://askubuntu.com/questions/1508490/ubuntu-server-on-raspberry-pi-5-is-not-connecting-to-the-internet

python typing check

• Docstring Linter
• pydocstyle
• Style Linter
• pylint
• pycodestyle
• Error Linter: 
• pyflake
• pylint
• Complexity Analysis
• mccabe 
• flake8
• flake8 = Pyflakes + pycodestyle + mccabe
• type checker: 
• mypy
• run it on command line
• run it with language server, for example: pylsp
• run it with Jupyter
• nb-mypy: configure it with ipython configuration or run it with command in jupyter
•  jupyter-lsp + pylsp
• Language server
• pyls and pylsp
• prefer to use pylsp instead of pyls, see link for detail.
• difference between different linter tools
• Pylint vs Pyflakes vs Flake8 vs autopep8 vs Bandit vs Prospector vs Pylama vs Pyroma vs Black vs Mypy vs Radon vs mccabe

racket

 racket is one of scheme dialect and I want to use racket to learn "the litte schemer". One of problem I meet is how to load file with scheme code (not racket code) into REPL and run relate function. In guile, it is very simple: guile -l my_function.scm. but in racket, it is little complex.

• with load (traditional scheme file, no #lang)

 it could work "racket -if <my_function.scm>" but my_function.scm should not start with "#lang racket". it is same with load function. 

• with module (racket file, with #lang)

Racket has concept of module, every file is module and each module need "initial-module-path" which is "The #lang at the start of a module file begins a shorthand for a module form"

First, like import in python, you could use (require my_function.scm) in source code and "-t " in command line to import a module, but you need to list which function is export by (provide function) in my_function.scm, or (provide (all-defined-out)) to export all functions. 

 -t <file>, --require <file> Like -e '(require (file "<file>"))' [*]

Another trick point is you need "racket -i -t my_function.scm" instead of "racket -t  my_function.scm -i". I don't know why but I guess it is related to "If -t/-l/-p/-u appears before the first -i/-e/-f/-r, -n is added".

Second, you could config initial-module in command line with "racket -I typed/racket" (#lang typed/racket in source code). The magic of of initial-module-path is you could define a new language with different syntax.

Third, you could always start "racket -i" and use ",enter my_function.scm" or "racket -i -e '(enter! "my_function.scm")'" to go to my_function namespace.