This document is an elementary introduction to string diagrams. It takes a computer science perspective: rather than using category theory as a starting point, we build on intuitions from formal language theory, treating string diagrams as a syntax with its semantics. After the basic theory, pointers are provided to contemporary applications of string diagrams in various fields of science.

翻译：本文档是对弦图的基础性介绍。它以计算机科学为视角：不将范畴论作为出发点，而是基于形式语言理论的直觉，将弦图视为一种具有语义的句法。在阐述基本理论之后，本文提供了弦图在科学各领域当代应用的相关指引。