sohang3112

(defn recursive-map [f coll]
     ;; is seq? right check??
     ;; it may not work for vectors
     ;; is there a coll? function?
     (if (seq? coll)
          (map #(recursive-map f %)     coll)
          coll)))

sohang3112

(defmacro my-doto [obj-expr & exprs]
  (let [obj-sym (gensym "object")
        actions (for [[method & args] exprs]
                  `(~method ~obj-sym ~@args))]
    `(let [~obj-sym ~obj-expr]
       ~@actions
       ~obj-sym)))

;; Example
(my-doto (java.util.HashMap.)

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Exercise 2

(defmacro def-vars [sym & exprs]
  `(do
     ~@(map-indexed (fn [i exp] `(def ~(symbol (str sym i)) ~exp)) 
                    exprs)))

Example Usage: (def-vars x (+ 1 2) 3 (* 2 5)) defines global variables x0, x1, x2.

sohang3112

Exercise 1

(defn has-number 
  "Does s expression have any number?"
  [sexp]
  (some number? (flatten sexp)))

;; Usage Examples
(has-number 'a)                          ;; => nil
(has-number '(a (b (c d) ((3)))))        ;; => true

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(defn print-inverted-triangle 
  "Print inverted triangle of given size, i.e.,
   the top right triangular half of a square of given size
   
   Example: `(print-inverted-triangle 5)` prints:
   ```
   *****
    ****
     ***
      **

sohang3112

Forth

Forth is an old stack-based language, primarily used in embedded / resource-constrained environments. I watched this Forth intro talk.

Resources - Books / Tutorials / Videos, etc.

• GForth Cheat Sheet
• Starting Forth - classic web book
• Easy Forth - web book
• A Beginner's Guide to Forth - online notes
• more online notes
• Learn Forth in Y Minutes

sohang3112

AWS Notes

All config, credentials are stored by aws in ~/.aws.

Note: In any command, a variable written in all capital (example: SSO-PROFILE-NAME) has to be replaced by the appropriate value.

Installing AWS CLI v2

Official install without root

The official docs only show how to install aws-cli as root user. If you don't have root access, you can follow these steps:

sohang3112

from __future__ import annotations


class Dummy:
    """
    Class for a dummy object, where we can do arbitary attribute / item / method chaining - all of them always return the object itself.
    Can also be called as a function, with any arguments or keyword arguments - again, the object itself is always returned.
    
    >>> obj = Dummy()
    >>> obj.x.y.z['key']('surprise', my='hurrah!') is obj 

sohang3112

AWS Lambda (Local Testing)

How to Run

1. Create a .env file in the same directory as this script like this, and fill in the Lambda Name and SSO Profile Name (left blank here):

AWS_LAMBDA_FUNCTION_NAME=
AWS_SSO_PROFILE_NAME=
DEBUG=True

2. Install all dependencies: pip install boto3 python-dotenv

sohang3112

# Source: https://stackoverflow.com/a/71542036/12947681
Get-ChildItem '.' -R -Filter *.zip | ForEach-Object {
     Expand-Archive $_.FullName "$($_.DirectoryName)/$($_.Basename)" -Force
     Remove-Item $_.FullName
}