BASIC Runtime Environment

This project implements a runtime environment for an extended version of Dartmouth BASIC V6.0. It includes:

• ✅ Full grammar definition (BNF/EBNF)
• ✅ Syntax checker (syntax.cpp) that validates structure, functions, and referenced line numbers
• ✅ Interpreter (interpreter.cpp) with:
  • Expression evaluation
  • Math functions including LOGX(X,Y)
  • Statement dispatch via switch structure
  • Executable LET and stub handlers for all other statements

Project Structure

• basic_runtime_env.cpp — Main command loop with LOAD, LIST, SAVE, RUN, SYNTAX, NEW, etc.
• syntax.cpp / syntax.h — Full syntax validator
• interpreter.cpp — Expression-aware interpreter
• BNF_with_LOGX.bnf — Grammar specification including extensions
• basic_test.bas — Example source code to test syntax and runtime features

Features

• ✔️ BNF-based design with extensions for:

  • Math and string functions
  • Control structures (WHILE/WEND, REPEAT/UNTIL)
  • Matrix operations (MAT)
  • File I/O (OPEN, PRINT#, INPUT#, CLOSE)
  • SEED, BEEP, PRINT USING, FORMAT lines

• ✔️ Syntax checker verifies:

  • Line references (GOTO, THEN, GOSUB, PRINT USING)
  • Matching loop pairs and nesting limits
  • Valid math and string function usage
  • Array dimensionality limits

• ✔️ Interpreter includes:

  • Recursive descent expression evaluation
  • Function call evaluation (SIN, POW, SQR, LOGX, etc.)
  • Variable storage and stub routing for full execution

Attribution

Most of the code in this project was generated with the assistance of ChatGPT, using structured prompts and iterative refinement to build a complete and testable BASIC interpreter.

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Built for educational use, retrocomputing interest, and showcasing parser/runtime design patterns.