Environment Application

Environment blocks bind execution conditions to enclosed steps.

with env(thermal = 37C, duration = 10min) {
    hold(sample = reactor);
}

Environment blocks describe operational conditions. They do not predict biological or chemical outcomes.

The public environment example is:

examples/minimal/public_env_readout.culs

Scalar Thermal Environment

Scalar thermal authoring uses a temperature and a duration.

with env(thermal = 37C, duration = 10min) {
    hold(sample = reactor);
}

For scalar thermal = ..., duration is required.

Pure Hold

Use hold(sample = ...) when the intended action is to keep a sample under the environment condition.

with env(thermal = 37C, duration = 10min) {
    hold(sample = reactor);
}

Rules:

• hold(sample = ...) is only valid inside with env.
• A pure hold block must write hold(...) explicitly.
• An empty with env(...) {} block is not valid.
• In a pure hold block, hold(...) is the only body statement.

Thermal Programs

For programmatic thermal control, use thermal_program(...).

let ramp = thermal_program(from = 60C, to = 95C, duration = 350s);

with env(thermal = ramp) {
    hold(sample = reactor);
}

Supported source shapes:

thermal_program(from = 37C, duration = 120min)
thermal_program(from = 60C, to = 95C, duration = 350s)

thermal_program(...) defines a single thermal segment. It does not carry cycles or staged PCR logic by itself. Multi-segment workflows compose thermal programs with explicit control flow.

When thermal is a thermal_program(...), the outer with env(...) must not also define duration.

Field Environment

Environment can also bind a field condition:

with env(field = mz_separation) {
    ...
}

Field environments do not use the scalar thermal duration rule.

Thermal Modifiers

co2 and rh are thermal-environment modifiers.

They require thermal and are not valid when thermal is a thermal_program(...).

Body Semantics

The body of with env(...) { ... } executes once in lexical order. If work must repeat, use an explicit repeat.

An environment block scopes execution conditions. It does not mean "simulate what happens biologically during this time."