L++ (LifeCode) – VS Code Extension

Semantic syntax highlighting and navigation for the L++ biological modeling language.

Features

Syntax Highlighting

Blue: Declaration keywords (pathway, organ, cell, bacterium, medium, etc.)
Green: Class instances (e.g., Nose from organ Nose, LB from medium LB)
Skyblue: Variables (e.g., K_Vrel, title, dimension, H+, 5'-deoxyadenosine)
Yellow: Function calls (e.g., Infection(...) in reaction Infection(...))
Purple: Kinetic parameters (k, kr, km, ki, v and their _function variants like k_function, kr_function)
Light green: Numbers and units (e.g., 55 M, 3.48 mM, 800 km)
Light purple: File/folder paths in dotted references (e.g., TreeOfLife.Bacteria.Ecoli.Medium in TreeOfLife.Bacteria.Ecoli.Medium.LB)

Declaration Tracking

The extension tracks variable and class instance declarations across entire files and colors all uses appropriately:

Explicit keyword declarations: organ Nose, float temperature, pathway myp
Bare-brace declarations: Core { ... }
Import aliases: TreeOfLife.Bacteria.Ecoli Ecoli
Dotted filepath references with cross-file resolution: TreeOfLife.Bacteria.Ecoli.Medium.LB

Hover information: Hover over any variable or class instance to see whether it's a class instance or variable, plus the declaration line number.

Go to definition: Cmd+Click (Mac) or Ctrl+Click (Windows/Linux) to jump to the line where a symbol is declared.

Dotted path navigation: Hover over or click any segment in a dotted path like TreeOfLife.Bacteria.Ecoli.Metabolism.MetaboliteConcentrations.Cytoplasm:

Intermediate segments reveal their folders in Explorer
Leaf symbols jump to declarations

Compound Names

Multi-part names connected by hyphens or commas are treated as single tokens:

L-alanine, D-glucose, 5,6,7,8-tetrahydrofolate render as atomic units
Ion notation: H+, HCO3-, NH4+
Apostrophe support: 5'-deoxyadenosine, alpha-D-ribose-5-phosphate
Scientific notation (e.g., 1e-5) is recognized as a number, not a compound

Extension Settings

File Icon Theme (Recommended)

The L++ extension includes a complete icon theme that combines:

Custom L++ icon for .lpp files (blue "L" mark)
Full Seti theme for all other file types (Python, JavaScript, JSON, TypeScript, Rust, etc.)

To enable:

Open the Command Palette (Cmd+Shift+P on Mac, Ctrl+Shift+P on Windows/Linux)
Select Preferences: File Icon Theme
Choose L++ File Icons

This gives you the complete Seti icon set plus L++'s distinctive file marker for .lpp files.

Example

person S
{
  disease_state = Susceptible
  count = 600000
}

// S is green (person S)
// disease_state is skyblue (variable)
// count is skyblue (variable)

reaction Infection(S -> I, k = 0.178)
// Infection is yellow (function call)
// k is purple (kinetic parameter)

Language Support

This extension adds syntax highlighting and semantic analysis for files with the .lpp extension, recognized as the L++ language.

For more information about L++ and LifeCode, visit the LifeCode repository.

L++

Omphalos Lifesciences