liquidcarbon / cesium

The most reactive of them all.

Project Cesium

How to design the all-powerful, hyperfine computational notebook?

Consider a simple Jupyter notebook with three cells:

# cell 0 (markdown)
"Title"

# cell 1 (code)
import sys

# cell 2
print(sys.prefix)

What is the data model for that? Let's write some sentences:

• each cell contains metadata and code
• cell metadata describes certain properties of the cell and logically links them to other cells (parent/child, usually an implicit relationship)
• cell code is a string of instructions that enable some of the following relationships:
  • references 0 to many global namespace objects
  • defines 0 to many global namespace objects
  • outputs a string (more on that later)

Specifically:

• cell 0 is a logical parent to cells 1 and 2
• cell 0 references nothing
• cell 0 defines nothing
• cell 0 outputs nothing
• cell 1 is a logical child of cell 0
• cell 1 references a global namespace object called import (a simplification)
• cell 1 defines a global object called sys, adding it to global namespace
• cell 1 outputs nothing
• cell 2 is a logical child of cell 0
• cell 2 references global objects sys and print
• cell 2 defines nothing
• cell 2 outputs the string representation of the sys.prefix attribute

Code execution

Will the code work the same on different machines? Probably not.
Will the code work the same at different times on the same machine? Probably yes.

The most interesting property of a code cell is its executions (Ex).

Pseudocode

class Cell:
  id: ULID
  metadata: CellMetadata
    type: Enum(markdown|language1|language2|...)
    description: str
    parent: cell_ulid
    child: List[Cell]
  code: str
  references: List[object]
  definitions: List[object]
  executions: List[Ex]
    env: env_ulid  # should come out of package/environment managers (venvs, Conda, Poetry, Pixi)
    start: ULID
    end: ULID
    output: str

TODO: elaborate

Name

The Cesium Standard is how we define time:

"The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom." —Bureau international des poids et mesures

The Cesium Notebook Standard is how we may come to define computational notebooks.