Notes.md

Introduction

base on expression eval ##from https://www.geeksforgeeks.org/expression-evaluation/

1. While there are still tokens to be read in, 1.1 Get the next token. 1.2 If the token is: 1.2.1 A number: push it onto the value stack. 1.2.2 A variable: get its value, and push onto the value stack. 1.2.3 A left parenthesis: push it onto the operator stack. 1.2.4 A right parenthesis: 1 While the thing on top of the operator stack is not a left parenthesis, 1 Pop the operator from the operator stack. 2 Pop the value stack twice, getting two operands. 3 Apply the operator to the operands, in the correct order. 4 Push the result onto the value stack. 2 Pop the left parenthesis from the operator stack, and discard it. 1.2.5 An operator (call it thisOp): 1 While the operator stack is not empty, and the top thing on the operator stack has the same or greater precedence as thisOp, 1 Pop the operator from the operator stack. 2 Pop the value stack twice, getting two operands. 3 Apply the operator to the operands, in the correct order. 4 Push the result onto the value stack. 2 Push thisOp onto the operator stack.
2. While the operator stack is not empty, 1 Pop the operator from the operator stack. 2 Pop the value stack twice, getting two operands. 3 Apply the operator to the operands, in the correct order. 4 Push the result onto the value stack.
3. At this point the operator stack should be empty, and the value stack should have only one value in it, which is the final result.

#Misc map find less or greator https://stackoverflow.com/questions/529831/returning-the-greatest-key-strictly-less-than-the-given-key-in-a-c-map #Flask template syntax https://flask.palletsprojects.com/en/2.1.x/tutorial/templates/ #jinja :Template Designer Documentation https://jinja.palletsprojects.com/en/3.1.x/templates/

#for WSL, to compile PyEng, run: sudo apt-get install python3.10-dev

#For uuid/uuid.h in linux -wsl, maybe need to run line below sudo apt-get install uuid-dev

for openssl required by http plugin

sudo apt-get install libssl-dev

#8/30/2022. Windows 11 Python install from Store, issues https://stackoverflow.com/questions/58754860/cmd-opens-windows-store-when-i-type-python #9/1/2022 srv.listen("::1", 8088) if use this , nodejs can't connect to change to srv.listen("::", 8088) or srv.listen("0.0.0.0", 8088) is OK

4/7/2023

find a bug: if xlang use c++ Compiler such as ver 20, and other app embeded xlang with lower version compiler, will crash, it happened on Linux