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Alberto Valverde albertov

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@sebfisch
sebfisch / gist:931419
Created April 20, 2011 14:10
Type Safe Interpreter for Simple Functional Language in Haskell
This literate Haskell program implements a type safe interpreter for a
simple functional language. Such an interpreter is the "hello world"
example for dependently typed languages and this program mimics it in
Haskell. Generalized algebraic data types and type families are
sufficient.
> {-# LANGUAGE GADTs #-}
> {-# LANGUAGE TypeFamilies #-}
> {-# LANGUAGE TypeOperators #-}
> {-# LANGUAGE MultiParamTypeClasses #-}
@sjoerdvisscher
sjoerdvisscher / soreifygadt.hs
Created September 1, 2012 22:49
Recovering sharing in a GADT
{-# LANGUAGE GADTs, TypeFamilies, FlexibleInstances, RankNTypes #-}
import Data.Reify
import Control.Applicative
import Data.Map
data Ast e where
IntLit :: Int -> Ast Int
Add :: Ast Int -> Ast Int -> Ast Int
BoolLit :: Bool -> Ast Bool
IfThenElse :: Ast Bool -> Ast e -> Ast e -> Ast e
@rgreenjr
rgreenjr / postgres_queries_and_commands.sql
Last active April 19, 2025 04:39
Useful PostgreSQL Queries and Commands
-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query
FROM pg_stat_activity
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
ORDER BY query_start desc;
-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query
FROM pg_stat_activity
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'
@colindean
colindean / generate_bitcoin_address.sh
Last active October 12, 2023 23:45
Bitcoin address generator in bash
#!/bin/bash
#
# This is free and unencumbered software released into the public domain.
#
# Requires bc, dc, openssl, xxd
#
# by grondilu from https://bitcointalk.org/index.php?topic=10970.msg156708#msg156708
base58=({1..9} {A..H} {J..N} {P..Z} {a..k} {m..z})
bitcoinregex="^[$(printf "%s" "${base58[@]}")]{34}$"
@chpatrick
chpatrick / Bake.hs
Last active September 15, 2018 04:20
Baked-in Storable Vectors Mark II
{-# LANGUAGE MagicHash, TupleSections, TemplateHaskell #-}
module Data.Vector.Storable.Bake(bake, unsafeFromAddrLen) where
import Data.Typeable
import qualified Data.Vector.Storable as VS
import Foreign
import GHC.Prim
import GHC.Ptr
import Language.Haskell.TH
@ali-abrar
ali-abrar / index.html
Last active June 8, 2020 04:47
Setting up Leaflet.js with Reflex.Dom
<!DOCTYPE html>
<html>
<head>
<!-- Add leaflet css -->
<link
rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css"
integrity="sha512-xwE/Az9zrjBIphAcBb3F6JVqxf46+CDLwfLMHloNu6KEQCAWi6HcDUbeOfBIptF7tcCzusKFjFw2yuvEpDL9wQ=="
crossorigin=""
/>
@maddouri
maddouri / build-static-python.sh
Created December 6, 2015 22:42
A simple script that builds static versions of Python and LibPython using musl-libc
#!/bin/bash
# set -eux
# This a simple script that builds static versions of Python and LibPython using musl-libc
# Find the associated article at: http://general-purpose.io/2015/12/06/compiling-python-and-libpython-statically-using-musl-libc/
WORKING_DIR="/code/static-python"
MUSL_PREFIX="/code/static-python/musl"
PY_PREFIX="/code/static-python/python"
@3noch
3noch / We've Moved.md
Last active January 26, 2017 17:50
NixOps wrapper script to use git-managed state files
@chrisdone
chrisdone / FieldTH.hs
Last active February 13, 2017 22:17
$(lens 'foo) -- handy one-off lens maker for record fields
{-# LANGUAGE TemplateHaskell #-}
-- | For when you have a record that doesn't have lenses derived for
-- it and you need a lens, just use @$(lens 'thefield)@ and away you go.
module Control.Lens.FieldTH where
import Language.Haskell.TH
lens :: Name -> Q Exp
lens name = do
[|\f r ->
fmap
$(lamE
@genekogan
genekogan / scrapeImages.py
Created February 22, 2017 11:49
scraping full size images from Google Images
from bs4 import BeautifulSoup
import requests
import re
import urllib2
import os
import argparse
import sys
import json
# adapted from http://stackoverflow.com/questions/20716842/python-download-images-from-google-image-search