cobord / hyperast

HyperAST

A (currently experimental) frontend to open-hypergraphs which lets you define open hypergraphs in a pointful (i.e., not point-free ) style. Here's a 1-bit adder circuit:

@hypergraph
def adder(x0, x1):
    y0 = x0 + x1 # sum
    y1 = x0 * x1 # carry
    return [y0, y1]

This builds an open hypergraph representing a string diagram like this:

Unlike python code, hypergraphs are fully combinatorial: there is no implicit assumption of 'causal' control flow. For example, we can define a hypergraphs with feedback, such as a ring oscillator:

@hypergraph
def ring_oscillator():
    x0 = node()
    x1 = ~x0 # we use x0 before declaring it - this is OK!
    unify(x0, ~x1) # connect x0 and x1
    return [x0]

This defines a string diagram like the one below:

Alternative interface

There is also a WIP alternative interface which inspects python syntax to define a hypergraph. Variables serve as hypernodes while functions and python operators are (labeled) hyperedges. The first example looks the same:

@hypergraph
def adder(x0, x1):
    y0 = x0 + x1 # sum
    y1 = x0 * x1 # carry
    return [y0, y1]

... but there is less overhead when writing hypergraphs with more unusual structure:

@hypergraph
def ring_oscillator():
    x1 = ~x0 # we use x0 before declaring it - this is OK
    x0 = ~x1
    return [x0]

Unlike the normal interface, this style does not execute the python code; it only inspects it.