Paxy — code in calm

Beginner's All-purpose Symbolic Instruction Code taught millions their first programs in the 1970s and 1980s.

Paxy revives the spirit of BASIC — not just as nostalgia, but as a deliberate choice: a simpler way to code.
Every line is a single command with arguments.

Where modern programming piles on frameworks, boilerplate, and ceremony, Paxy takes the opposite path.

• Simplicity first. A few clear commands (LET, IF, PNT, RNG) are enough to get started.
• Immediate feedback. Programs run top-to-bottom, exactly as written.
• Calm and predictable. Deterministic and synchronous: the computer follows your steps.
• Accessible to everyone. If you can type, you can code.
• Batteries included. Commands cover the most common use cases.

Bring your vibes

Paxy is ideal for AI-assisted coding. Modern AI tools stumble on complex syntax, indentation, or hidden imports.
Paxy avoids all that. One command per line, plain arguments, no boilerplate — the perfect partner for AI.

• Copy-paste friendly. Each line is self-contained.
• Hard to break. No braces, decorators, or indentation traps.
• Composable snippets. Loops, prints, or conditionals can be dropped in like building blocks.
• Readable by humans and AI. Simple, declarative steps.
• No ceremony. Forget imports and types — just write commands.

Usage

paxy filename.paxy will compile and run the paxy file.

Install for development

1. You need Python 3.12, 3.13 or 3.14.

Older Python versions are untested and unlikely to ever be supported.

I use pyenv to use multiple Python versions on my computer: https://github.com/pyenv/pyenv

• Linux: curl -fsSL https://pyenv.run | bash
• Mac: brew install pyenv
• Win: https://github.com/pyenv-win/pyenv-win/blob/master/docs/installation.md

Then add your desired version of Python:

• pyenv install 3.13.7
• pyenv local 3.13.7

2. Create virtual environment:

• python -m venv deps
• source deps/bin/activate

3. Install dependancies:

• pip install -e .[dev]

4. Run tests

• pytest

5. To get Debug information, run with PAXY_DEBUG=1 and it will output information to /tmp/paxy_debug.txt

Rebuilding documentation

• cd docs
• make html

Make a package for PyPi

• python -m build

Commands

When writing paxy files, you can use low-level Python bytecode names (as in the dis module). But we provide high level BASIC Commands:

Commands

When writing paxy files, you can use low-level Python bytecode names (as in the dis module).
But we provide high-level BASIC-style commands as a friendlier layer.
These are compiled into Python 3.13 bytecode instructions at build time.

CMP

CMP dst lhs cmp rhs
Evaluate lhs <cmp> rhs (where <cmp> is ==, !=, <, <=, >, >=) and store the boolean result in dst.

DEC

DEC x
Decrement a variable: x = x - 1.

GOS

GOS dst fn [args...]
Call function fn with arguments and store the return value in dst.

IGL

IGL name [elem1 elem2 ...]
Create a frozenset from the given elements. Fast-path: all literals become one constant; otherwise build at runtime.

IF

IF lhs cmp rhs label
Compare lhs <cmp> rhs; if true, jump to label.

IMP

IMP "module"
Import a module by name. Equivalent to __import__("module").

INC

INC x
Increment a variable: x = x + 1.

IN

IN dst needle haystack
Store boolean result of needle in haystack into dst.

INP

INP x
Prompt for input: x = input().

IS

IS dst lhs rhs
Store boolean result of lhs is rhs into dst.

NIS

NIS dst lhs rhs
Store boolean result of lhs is not rhs into dst.

LBL

LBL name
Define a jump target.

LET

LET name value
Assign a value.
LET name lhs op rhs also supports operators: arithmetic, comparison, is, in, etc.

MAP

MAP name "k1" v1 "k2" v2 ...
Create a dict with string keys.

MAD

MAD m k v
Set m[k] = v.

MAL

MAL m k
Delete m[k].

NIN

NIN dst needle haystack
Store boolean result of needle not in haystack into dst.

PAR

PAR dst1 dst2 expr1 expr2
Parallel assignment: dst1, dst2 = expr1, expr2.

PNT

PNT [value]
Print a value (or a blank line).

RNG … RNE

RNG name start end ...body... RNE

Loop from start up to (but not including) end, assigning each value to var.

RET

RET
Return 0.
RET value
Return the given value.

ROW

ROW name [elem1 elem2 ...]
Create a row of data.

SUB ... SBE

SUB name [params...] ... body ... SBE

Define a function. Use RET within it.

VEC

VEC name [elem1 elem2 ...]
Create a list.

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These BASIC commands are lowered into the intermediate representation (paxy.ir) and then into Python bytecode. You can always mix them with raw CPython opcode names if you want finer control.

• VEC — Create list: VEC v 1 2 3 → v = [1,2,3].

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Command Reference (Cheat Sheet)

Command	Purpose	Example
CMP	Compare values and store boolean result	CMP r a == b
DEC	Decrement a variable	DEC x → x = x - 1
GOS	Call function, store result	GOS z add x y
IGL	Create frozenset	IGL s 1 2 3 → s = frozenset({1,2,3})
IF	Conditional jump	IF a < b loop_start
IMP	Import a module	IMP "math"
INC	Increment a variable	INC x → x = x + 1
IN	Membership test	IN r x arr → r = (x in arr)
INP	Read from stdin	INP name → name = input()
IS	Identity test	IS r a b → r = (a is b)
NIS	Negated identity test	NIS r a b → r = (a is not b)
LBL	Define a jump target	LBL loop_start
LET	Assign value or expression	LET x 10, LET y a + b
MAP	Create dictionary with string keys	MAP m "a" 1 "b" 2 → m = {"a":1,"b":2}
MAD	Insert into dict	MAD m "c" 3 → m["c"]=3
MAL	Delete from dict	MAL m "a" → del m["a"]
NIN	Negated membership test	NIN r x arr → r = (x not in arr)
PAR	Parallel assignment	PAR a b x y → a, b = x, y
PNT	Print a value (or newline)	PNT x
RNG	Loop over a range of integers	RNG i 1 5 … RNE → for i in 1..4
RET	Return from SUB (default 0 if no value)	RET y
ROW	Create tuple	ROW t 1 2 3 → t = (1,2,3)
SUB	Define a subroutine	SUB add a b ... RET a+b SBE
VEC	Create list	VEC v 1 2 3 → v = [1,2,3]