Developer Builds Three-Phase Mini Compiler From Scratch Using TypeScript

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A university student built a mini compiler called Frog Mini Compiler as part of a compiler design assignment, using only TypeScript, HTML, and CSS without any compiler-building libraries. The project targets a small teaching language called Frog, which supports variables, conditionals, print statements, and repeat-until loops. The compiler implements three classic phases: a lexer that tokenizes raw source code, a parser that checks grammar rules and builds expression trees recursively, and a semantic analyzer that tracks variable types and values while executing the program. A simple web interface ties all three phases together, allowing users to run each phase independently and inspect intermediate results. The hands-on project gave the developer a practical understanding of how compilers transform source code into executable output.

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