🟰Default Evaluation
Example, weight force of a cucumber:
m_cuc = 400 g;
force = m_cuc * _g0 → force = 3.9226 N
By default, Calcumber evaluates expressions in three steps:
1. Variable substitution → 400 g * 9.80665 m/s^2
2. Arithmetic evaluation → 3922.66 g*m/s^2
3. Unit simplification → 3.92266 N
This behavior can be influenced by the functions eval and lazy.
⚡Eval
The eval function forces another evaluation.
A modified cucumber weight force example:
force = m_cuc * _g0→ force ➔ m_cuc * 9.80665 m/s^2
m_cuc = 400 g;
force ➔ m_cuc * 9.80665 m/s^2
force is replaced by its definition only
eval(force) → 3.92266 N eval forces another evaluation
Want to calculate for a smaller cucumber? Just define a local variable as argument for eval.
eval(force, m_cuc = 350 g) → 3.4323275 N
💤Lazy
The lazy function prevents evaluation.
m_cuc = 400 g; definine the mass
force = m_cuc * _g0 ➔ force = 3.9226 N
➔ The expression is evaluated and then assinged to force.
force = lazy(m_cuc * _g0 ➔ force = m_cuc * _g0
➔ The unevaluated expression is assinged to force.