Ekaterina mAlishera

## gist:3744867

      
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                malandrina
                / gist:3744867
            
            
              Created
              September 18, 2012 18:26
            
              
                Implementing a Reverse Polish Notation Calculator in Ruby
              
          
    Implementing a Reverse Polish notation calculator in Ruby

A couple weeks ago I had a go at implementing an RPN calculator in Ruby. I knew I wanted the calculator to function by popping operands out of an array populated with the values of the input expression, operating upon the operands with the appropriate operator, and pushing the result back into the stack of operands.
I was able to implement this in version 1, but it took forever and the resulting code was not very beautiful. Why?


I started coding before I had a thorough understanding of RPN
Wait, 20 10 5 4 + * - is what now?


## golang-nuts.go
package main

import (
	"fmt"
	"time"
)

// Suggestions from golang-nuts
// http://play.golang.org/p/Ctg3_AQisl

## reflection.go
package main

import (
	"fmt"
	"reflect"
)

type Foo struct {
	FirstName string `tag_name:"tag 1"`
	LastName  string `tag_name:"tag 2"`

## current-dir-in-iterm-tab-title.sh
# put this in your .bash_profile
if [ $ITERM_SESSION_ID ]; then
  export PROMPT_COMMAND='echo -ne "\033];${PWD##*/}\007"; ':"$PROMPT_COMMAND";
fi

# Piece-by-Piece Explanation:
# the if condition makes sure we only screw with $PROMPT_COMMAND if we're in an iTerm environment
# iTerm happens to give each session a unique $ITERM_SESSION_ID we can use, $ITERM_PROFILE is an option too
# the $PROMPT_COMMAND environment variable is executed every time a command is run
# see: ss64.com/bash/syntax-prompt.html

## xmerl_demo.ex
defmodule XmlNode do
  require Record
  Record.defrecord :xmlAttribute, Record.extract(:xmlAttribute, from_lib: "xmerl/include/xmerl.hrl")
  Record.defrecord :xmlText, Record.extract(:xmlText, from_lib: "xmerl/include/xmerl.hrl")

  def from_string(xml_string, options \\ [quiet: true]) do
    {doc, []} =
      xml_string
      |> :binary.bin_to_list
      |> :xmerl_scan.string(options)

## iterm2-solarized.md

      
              2 files
            
          
              1628 forks
            
          
              493 comments
            
          
              8809 stars
            
          
                kevin-smets
                / iterm2-solarized.md
            
            
              Last active
              July 2, 2024 12:33
            
              
                iTerm2 + Oh My Zsh + Solarized color scheme + Source Code Pro Powerline + Font Awesome + [Powerlevel10k] - (macOS)
              
          
    Default


Powerlevel10k


## postgres-cheatsheet.md

      
              1 file
            
          
              1133 forks
            
          
              66 comments
            
          
              3515 stars
            
          
                Kartones
                / postgres-cheatsheet.md
            
            
              Last active
              July 2, 2024 22:38
            
              
                PostgreSQL command line cheatsheet
              
          
    PSQL

Magic words:
psql -U postgres
Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)


## app.css
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font: 13px Helvetica, Arial;
}

## bash-cheatsheet.sh
#!/bin/bash
#####################################################
# Name: Bash CheatSheet for Mac OSX
#
# A little overlook of the Bash basics
#
# Usage:
#
# Author: J. Le Coupanec
# Date: 2014/11/04

## index.html
<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <title>Normal Plot</title>
    <meta name="description" content="">
	<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js" charset="utf-8"></script>
	<link rel="stylesheet" href="style.css" type="text/css" charset="utf-8"></link>
	package main

	import (
	"fmt"
	"time"
	)

	// Suggestions from golang-nuts
	// http://play.golang.org/p/Ctg3_AQisl
	# put this in your .bash_profile
	if [ $ITERM_SESSION_ID ]; then
	export PROMPT_COMMAND='echo -ne "\033];${PWD##*/}\007"; ':"$PROMPT_COMMAND";
	fi

	# Piece-by-Piece Explanation:
	# the if condition makes sure we only screw with $PROMPT_COMMAND if we're in an iTerm environment
	# iTerm happens to give each session a unique $ITERM_SESSION_ID we can use, $ITERM_PROFILE is an option too
	# the $PROMPT_COMMAND environment variable is executed every time a command is run
	# see: ss64.com/bash/syntax-prompt.html
	defmodule XmlNode do
	require Record
	Record.defrecord :xmlAttribute, Record.extract(:xmlAttribute, from_lib: "xmerl/include/xmerl.hrl")
	Record.defrecord :xmlText, Record.extract(:xmlText, from_lib: "xmerl/include/xmerl.hrl")

	def from_string(xml_string, options \\ [quiet: true]) do
	{doc, []} =
	xml_string
	\|> :binary.bin_to_list
	\|> :xmerl_scan.string(options)
	* {
	margin: 0;
	padding: 0;
	box-sizing: border-box;
	}

	body {
	font: 13px Helvetica, Arial;
	}
	#!/bin/bash
	#####################################################
	# Name: Bash CheatSheet for Mac OSX
	#
	# A little overlook of the Bash basics
	#
	# Usage:
	#
	# Author: J. Le Coupanec
	# Date: 2014/11/04
	<!DOCTYPE html>
	<html>

	<head>
	<meta charset="utf-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
	<title>Normal Plot</title>
	<meta name="description" content="">
	<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js" charset="utf-8"></script>
	<link rel="stylesheet" href="style.css" type="text/css" charset="utf-8"></link>