This question evaluates proficiency in string parsing, tokenization, escape-sequence handling, and input validation required to convert simplified Markdown-style link syntax into HTML anchors without using regular expressions.
Implement a function that converts simplified link syntax text into an HTML anchor tag <a href="url">text</a> across an entire input string. Constraints: do not use regular expressions; rely only on basic string operations (e.g., indexOf, split, substring). Requirements: