Objective

Build a tiny interpreter for an esoteric language whose entire instruction set fits in eight ASCII characters and whose only state is a 2048-byte tape of unsigned cells plus a single data pointer.

Steps

• The source code to execute is passed as the single command-line argument; if the program does not receive exactly one argument, write nothing and exit.
• Allocate a tape of 2048 unsigned-char cells, all initialised to zero, with a data pointer starting at cell 0.
• Recognise only these eight instructions: > moves the pointer one cell right, < moves it one cell left, + increments the current cell, - decrements it, . writes the current cell as a byte to stdout, , reads one byte from stdin into the current cell.
• Implement loops: [ jumps past the matching ] when the current cell is zero, and ] jumps back to the matching [ when the current cell is non-zero. Brackets nest and are guaranteed to be balanced.
• Every other character in the input is treated as a comment and skipped silently, programmers love hiding jokes between the operators.
• The only allowed library function is write.

Objective

Build a tiny interpreter for an esoteric language whose entire instruction set fits in eight ASCII characters and whose only state is a 2048-byte tape of unsigned cells plus a single data pointer.

Steps

• The source code to execute is passed as the single command-line argument; if the program does not receive exactly one argument, write nothing and exit.
• Allocate a tape of 2048 unsigned-char cells, all initialised to zero, with a data pointer starting at cell 0.
• Recognise only these eight instructions: > moves the pointer one cell right, < moves it one cell left, + increments the current cell, - decrements it, . writes the current cell as a byte to stdout, , reads one byte from stdin into the current cell.
• Implement loops: [ jumps past the matching ] when the current cell is zero, and ] jumps back to the matching [ when the current cell is non-zero. Brackets nest and are guaranteed to be balanced.
• Every other character in the input is treated as a comment and skipped silently, programmers love hiding jokes between the operators.
• The only allowed library function is write.