jngbng

(ns core-logic.core
  (:require [clojure.core.logic :as logic]
            [clojure.core.logic.fd :as fd]))


;;; 출처: https://blog.taylorwood.io/2018/05/10/clojure-logic.html
(defn- productsumo
  "Sigma (vars_i * denoms_i) = sum 을 만족하는가."
  [vars denoms sum]
  (logic/fresh [vhead vtail

jngbng

(ns core-logic.core
  (:require [clojure.core.logic :as logic]
            [clojure.core.logic.fd :as fd]))

;;; 현명한 딸 셋을 두 상인이 사과 90개를 가져와
;;; 첫째에게 50개, 둘째에게 30개, 셋째에게 10개를 주며
;;; 그것을 팔아오되 첫째가 만약 10개를 1원에 팔면
;;; 둘째, 셋째도 똑같이 10개를 1원에 팔아야 한다는 조건을 걸었다.
;;; 하지만 팔아서 번 돈은 셋이 모두 같아야 한다.
;;; 어떻게 해야 조건대로 팔 수 있을까?

jngbng

git fsck --full --no-reflogs --unreachable --lost-found | cut -d ' ' -f 3 | xargs -n 1 git log -n 1 --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit

jngbng

CREATE OR REPLACE FUNCTION jsonb_remove_keys(
	jdata JSONB,
	keys TEXT[]
)
RETURNS JSONB AS $$
DECLARE
	result JSONB;
	len INT;
	target TEXT;

jngbng

set timezone='Asia/Seoul';
show timezone;

SELECT '2018-12-01 00:00:00'::timestamp at time zone 'GMT';
SELECT (timestamp '2018-12-01 00:00:00') at time zone 'GMT';
-- 2018-12-01 09:00:00+09

SELECT '2018-12-01 00:00:00' at time zone 'GMT';
SELECT (date '2018-12-01') at time zone 'GMT';
SELECT '2018-12-01 00:00:00'::timestamp with time zone at time zone 'GMT';

jngbng

// validation.cpp

/** Store block on disk. If dbp is non-nullptr, the file is known to already reside on disk */
static bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp, bool* fNewBlock)
{
  // ...
  // Header is valid/has work, merkle tree and segwit merkle tree are good...RELAY NOW
  // (but if it does not build on our best tip, let the SendMessages loop relay it)
  if (!IsInitialBlockDownload() && chainActive.Tip() == pindex->pprev)
    GetMainSignals().NewPoWValidBlock(pindex, pblock);

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// txdb.cpp
static const char DB_BLOCK_INDEX = 'b';

bool CBlockTreeDB::LoadBlockIndexGuts(const Consensus::Params& consensusParams, std::function<CBlockIndex*(const uint256&)> insertBlockIndex)
{
  std::unique_ptr<CDBIterator> pcursor(NewIterator());

  // Start from key b000...
  pcursor->Seek(std::make_pair(DB_BLOCK_INDEX, uint256()));

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/********************
 * Do part
 ********************/

// undo.h
class CTxUndo
{
public:
  // undo information for all txins // COMMENT: spent coin by txins
  std::vector<Coin> vprevout;

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// rest.cpp

// will be called with http request /rest/block/[BLOCK_HASH_VALUE]
static bool rest_block(HTTPRequest* req, const std::string& strURIPart, bool showTxDetails)
{
  // ...
  uint256 hash; // will be parsed from `strURIPart`
  
  CBlock block;
  CBlockIndex* pblockindex = nullptr;

jngbng

// bitcoin core (0d7e0a328) serialize/deserialize. 

// Stream s;
// CBlock block;
// s >> block;

// internal above code.

// Step1: operator overloading