The pf

Forgot what that stands for. pifuck?

The representation of input

1. All of standard input is read before starting the program.
2. Bijective encoding
3. Translate to base-pi
4. Input is in register 0

The registers

A register contains a string, initially empty

• Register 0: input register, filled with digits 0..3 (base-pi representation of input).
• Register 1: output register, writing to this register will end the program and go to the output stage. Contains pseudo-digits 0..3 (only the low 2 bits will be considered when converting from base-e to a number to output).
• The program may use any number of auxiliary registers numbered 2 and up.

The flag

There is one flag bit, set to 1 whenever a replacement is made. It is cleared by conditional GOTO.

The program

Each command-line argument to the interpreter is one adjustment in the program, numbered accordingly (1-based indexing).

• Find/replace adjustment: I/pat/repl/O Replace pat with repl everywhere it appears in input register I, writing the output into register O. If a replacement is made, set the flag.

• Unconditional GOTO: I/ (I > 0) Jump to adjustment index I.

• Conditional GOTO: -I/ (I > 0) Jump to adjustment index I if the flag is set.

The representation of output

1. The adjusted output is stored in register 1
2. Translate from base-e
3. Bijective decoding
4. Output to stdout

The example program

./pf 0/0/20birthday21repatriate02draft20200flammulatedThraxerythrean020depth00/1 </dev/null

Or e.g.

echo | ./pf 0/100/20birthday21repatriate02draft20200flammulatedThraxerythrean020depth00/1

The constant string conversion program

The example program(s) were generated with the help of the conversion program:

echo "Hello world!" | ./conv

The build instructions

Run make to build pf (the interpreter) and conv (the string converter).

Requires libmpfr and libgmp and their development headers.

The license

This software is licensed under the MIT license. See the LICENSE file.