dmalikov

Suppose there is a commit C which have a single parent commit P.

Let's say that TC and TP are the corresponding tree objects.

Why git diff P C is not always equal to git diff-tree TP TC -p?

---

Why they should be equal?

dmalikov

target hw1
    sources
        hw1.mlb
        hw1.main.sml
    end

    option compiler = mlton
    option output = hw1
end

dmalikov

Various blog posts related to Nix and NixOS

---

General

• https://nixos.org/wiki/Main_Page Nix wiki. Awesome resource containing huge amount of manuals and documentation with examples.
• http://aflatter.de/nixos/ Alexander Flatter - NixOS. Installing NixOS inside a VirtualBox with a real-world configuration.nix example.
• http://lethalman.blogspot.it/search/label/nixpills Luca Bruno - Nix Pills. Series of posts describing how to install nix into some environment and how to use it.
• http://looprecur.com/blog/from-ubuntu-to-nixos/ Tim Sears - From Ubuntu to NixOS. Talk about experience migrating from Ubuntu to NixOS.

dmalikov

 instance FromJSON Database where
-  parseJSON (Object o) = Database
-    <$> o .: "id"
-    <*> o .: "_rid"
-    <*> o .: "_ts"
-    <*> o .: "_self"
-    <*> o .: "_etag"
-    <*> o .: "_colls"
-    <*> o .: "_users"
+  parseJSON (Object o) =

dmalikov

#!/bin/bash

# wow so bash such fast very O(n^2*log(n)^2)

for author in `git log --format='%ae' | sort -u`; do
    changes=`git log --author=$author --pretty=tformat: --numstat | awk '{ add += $1 ; subs += $2 } END { printf "%s ++ / %s --\n",add,subs }'`
    commits=`git log --author=$author --oneline | wc -l`
    echo "$author: $commits commits / $changes"
done | sort -rn -k2

dmalikov

open System
open System.Net
 
type Stock(symbol : string) = class
    let url =
        "http://download.finance.yahoo.com/d/quotes.csv?s=" + symbol + "&f=sl1d1t1c1ohgv&e=.csv"
 
    let mutable _symbol = String.Empty
    let mutable _current = 0.0
    let mutable _open = 0.0

dmalikov

What is going on here is creating 2 streams with numbers from 1 to 100000 sorting randomly and finding with grep all lines that each of them contains. All of them, actually. -c flag is a shortcut for `| wc -l`, nothng more.

$> n=100000; time grep -f <(seq 1 $n | sort -R) <(seq 1 $n | sort -R) -c 
100000
grep -f <(seq 1 $n | sort -R) <(seq 1 $n | sort -R) -c  148.65s user 0.28s system 98% cpu 2:31.89 total


$> n=100000; time grep -xF -f <(seq 1 $n | sort -R) <(seq 1 $n | sort -R) -c 
100000
grep -xF -f <(seq 1 $n | sort -R) <(seq 1 $n | sort -R) -c  0.34s user 0.01s system 26% cpu 1.315 total

dmalikov

import Control.Monad (($), forM, undefined)

main = forM [] $ undefined

dmalikov

Lemma mult_0_r : forall n:nat,
  n * 0 = 0.
Proof.
  intros n. induction n as [| n'].
  (* Case "n = 0". *)
    simpl.
    reflexivity.
  (* Case "n = S n'". *)
    simpl.
    rewrite -> IHn'.

dmalikov

α(L,P,R) :- β(L,P,R,0).

β([H|T],P,R,A) :- pow(H,P,X), β(T,P,R,A + X).
β([H],P,R,A) :- pow(H,P,X), R is A + X.

γ(X, Y, P) :- α(X, P, A), α(Y, P, B), A == B, !.

main(A) :- findall(X, (between(0,100,X), γ([0,3,5,6,9,10,12,15], [1,2,4,7,8,11,13,14], X)), A).