Welcome to Graphcal¶

Graphcal is a type-safe, unit-aware, Git-friendly reactive programming language for engineering calculations. It replaces spreadsheets and ad-hoc scripts with a single typed, version-controlled computation graph.

Quick Example¶

The Tsiolkovsky rocket equation in Graphcal:

dim Velocity = Length / Time;
dim Acceleration = Length / Time^2;

param dry_mass: Mass = 1200.0 kg;
param fuel_mass: Mass = 2800.0 kg;
param isp: Time = 320.0 s;
const node g0: Acceleration = 9.80665 m/s^2;

node v_exhaust: Velocity = @isp * @g0;
node mass_ratio: Dimensionless = (@dry_mass + @fuel_mass) / @dry_mass;
node delta_v: Velocity = @v_exhaust * ln(@mass_ratio);

Run it:

$ graphcal eval rocket.gcl
dry_mass   = 1200 kg
fuel_mass  = 2800 kg
isp        = 320 s
g0         = 9.80665 m/s^2
v_exhaust  = 3138.128 m/s
mass_ratio = 3.333333
delta_v    = 3778.220768 m/s

Why Graphcal?¶

• Type safety -- Dimension mismatches are caught at compile time.
• Unit awareness -- Define physical dimensions, attach units, and convert between them. The compiler enforces dimensional consistency. No more Mars Climate Orbiter failures.
• Reactive computation -- Define a DAG of parameters and nodes. Change an input and all dependent values update automatically.
• Git-friendly -- Plain text .gcl files that diff and merge cleanly. No binary spreadsheets.
• Live editor experience -- The LSP server provides inlay hints that display computed values inline, turning your editor into a live calculation sheet.

Getting Started¶