3.725254969642999e-321

3.725254969642999e-321 is an esoteric programming language centered around the IEEE 754 standard for floating-point numbers.

At a glance

• Stack-based
• Code and data both live on the same
  • This isn't really used in any interesting way, though
• The stack must always consist only of valid IEEE 754 64-bit NaN values, or the program will crash
• Generally hard to use and not very useful

Usage

Usage: nim c -r main <path-to-source-file>

For example: echo "abc" | nim c -r main examples/cat

Terminology

• the zero nan: 0111111111111000000000000000000000000000000000000000000000000000, perhaps the simplest valid 64-bit NaN value.

• nannification and denannifiction: Nannification is the process of taking a value and wrapping it into a NaN value. This is typically done by mapping x to x | zero_nan. Denanification is the reverse process, mapping x to x & ~zero_nan.

• a signed or unsigned float: A float is signed if the sign bit (leftmost bit) is 1; otherwise, it is unsigned.

Syntax

The first thing to understand about 3.725254969642999e-321 is that a program is entirely defined by a sequence of floating-point values, called its stack. Both the program code and its data are stored on the stack.

A 3.725254969642999e-321 program is written as a sequence of words, but each word maps directly to a floating-point value:

• A symbol, which is a sequence of characters from abcdefghijklmnopqrstuvwxyz0123456789<>()[]{}~!@#$%^&*-+_=?:;,.'"/|``, is converted to an integer by interpretering the symbol as a number where the above characters are digits. This value is then nannified and then casted to a float. Uppercase letters are also allowed but are normalized to lowercase. Symbols may not be more than 8 characters long; above this, the data would overlap with the 1s required for nannification.
• A numeral, which is either b'DIGITS, x'DIGITS, or a'CHARS, optionally prefixed with nan/, designates a float more directly: the digits are converted either from binary, hexadecimal, or ascii (padded to 8 bits), nannified if the numeral begins with nan/, and casted to a float.

Execution

Once the code has been parsed into a stack, it may be executed. Before and after each instruction during execution, the stack must consist only of valid IEEE 754 NaN values, or the program will crash.

The interpreter keeps track of the current instruction with an 'instruction pointer', which starts at 0. It repeatedly gets the instruction at the location in the stack given by the instruction pointer and performs the associated action. Except for in certain cases, such as those of loops, the instruction pointer is then incremented.

Examples

See examples/

Instructions

Syntax	Semantics
stop	Terminate the program
{	Push the current value of the instruction pointer onto the top of the stack, nannified
}	Pop the top value, denannify it, and set the instruction pointer to it
[	If the top value is signed, noop. If it is unsigned, advance the instruction pointer to the matching ].
]	Noop
push	Push the value after this instruction onto the top of the stack, and then advance to after the value
dup	Duplicate the top item on the stack
swap	Swap the top two values of the stack
drop	Remove the top value from the stack
++	Increment the top value of the stack, treating it as an unsigned integer
--	Decrement the top value of the stack, treating it as an unsigned integer
+	Pop the top two values, add them as floats, and push the result.
-	Pop the top two values, subtract them as floats, and push the result.
*	Pop the top two values, multiply them as floats, and push the result.
/	Pop the top two values, divide them as floats, and push the result.
**	Pop the top two values, exponentiate them as floats, and push the result.
neg	Toggle the sign bit on the top value of the stack
rotr	Rotate the bits of the top value of the stack to the right, wrapping
rotl	Rotate the bits of the top value of the stack to the left, wrapping
get/char	Read a character from stdin, nannify it, and push it onto the stack. If stdin is empty, it is read as \0.
put	Display the top value of the stack
put/all	Display the entire stack
put/char	Display the top value of the stack, denannified and as a character
put/bits	Display the top value of the stack as a length-64 bitstring

Errors

If your program crashes, it will spit out an error code.

Error	Type	Stands for	Meaning
NvS	Parsing	"not valid symbol"	A symbol is invalid
NvN	Parsing	"not valid numeral"	A numeral is invalid
NeN	Runtime	"not entirely NaNs"	You have introduced a non-NaN value onto the stack
NiB	Runtime	"not in bounds"	The instruction pointer has moved off the stack
NaI	Runtime	"not an instruction"	Unknown instruction encountered
NpI	Runtime	"not paired instruction"	An { or [ is unpaired