CFDL

Expressions

An amount is an expression, evaluated once per period:

stream tower.rent on entity asset.tower inflow currency USD {
  schedule every month from 2026-01 to 2035-12
  amount = 25000 * pow(1.03, time.t / 12.0)
}

Expressions are pure and total. There are no statements, no assignment, and no loops, so the same inputs always produce the same number.

What is in scope

BindingHolds
time.*where you are — time.t is the period index, time.date its date
inputs.*values declared with assume, including sampled ones
model.*model-level facts such as the currency
entity.*attributes of the entity the stream belongs to
cfg.*run configuration, such as the discount rate
obs.*observed series a curve provides
state.*declared states, at the current period
prevthis state's previous value — inside a state's next only

Three more are bound inside a waterfall step:

BindingHolds
remainingwhat is left in the pot at this step
paid.<step>what an earlier step actually paid
owed.<step>what an earlier step would have paid, unbounded

Inside a pack's lowering rule, {{contract.*}} placeholders are substituted before the expression is parsed — so by the time it evaluates, a contract term is a literal.

Operators

Arithmetic + - * / %, comparison == != < <= > >=, and boolean and or not. if(condition, then, else) chooses between two values and is an expression, not a branch — both arms are the same type.

Numbers

All arithmetic is floating point. Where a source rounds — a workbook that computes on already-rounded figures — reach for round_to and match the source's method rather than restating its answer, so the model reproduces the published number by doing what the publisher did.

Functions

Generated from the engine's own dispatch table, so this is exactly what the current build accepts.

Arithmetic — abs, min, max, clamp, exp, ln, pow, sum, avg

Rounding — round, round_up, round_down, round_to

Dates — date, parse_date, edate, eomonth, days_between, months_between, year_frac, roll, is_business_day, add_business_days

Time value of money — pv, fv, pmt, ipmt, ppmt, nper, rate

Domain — macrs_rate, cpr_to_smm, cpr_to_periodic

Choice — if

Curves — curve_value

Series folds — series_sum, series_avg

37 functions.

Related