Programming languages

GraalVM

  GraalVM is a universal virtual machine for running applications written in JavaScript, Python, Ruby, R, JVM-based languages like Java, Scala, Kotli n, Clojure, and LLVM-based languages such as C and C++.GraalVM removes the isolation between programming languages and enables interoperability in a shared runtime. It can run either standalone or in the context of …

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WebAssembly

WebAssembly (often shortened to Wasm) is a standard that defines a binary format and a corresponding assembly-like text format for executables used by web pages. [….] WebAssembly code is intended to be run on a portable abstract structured stack machine,[27] which is designed to be faster to parse than JavaScript, as well as faster to execute,[21] and to enable very compact code representation.In …

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Comments are evil?

In the 1980 comments were used to reduce the “gap” between unstructured code and “rationale” behind the code. C/64 Peek and poke where oscure. Gosub on function pointed by numbers was bad 8-bit systems was tight on command names and so on (think to write a python interpreter in Arduino/bbc:Micro, or look at the memory …

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SQL: One of the most valuable skills – Craig Kerstiens

I admit it. I suffered from an “algebra narcoleptic syndrome” during my relational database lessons at University (1996 circa). Ok it is a fake. But it seems so real on these days. I was unable to avoid sleeping. I learned to love SQL after some years and now I think SQL is the most powerful, …

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IoT Async

Qualche mese fa avevo sviluppato una applicazione IoT per misurare la temperatura e spedire i dati ad una coda mqtt. Poi c’era uns server che colelzzionava i dati. Totale: tre server, con tre punti di fallimento ma architettura molto “cool” In effetti però la potenza dei moderni chip embedded è tale che è possibile implementare …

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Removing duplicate rows in PostgreSQL, Oracle and SQLite

Sometimes you need to remove nasty duplicate on a table, based on a subset of the column. Oracle trick:

Postgresql equivalent is ctid, so you can try something like

SQLite demo:

  Also take a look at this old post on postgresql mailing list, if you incur in an older PostgreSQL version …

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