Particles.spec

How the particle system reads an emitter spec. Each reader checks one field against the shapes it takes and raises a refusal naming the field and those shapes; level is how far out the refusal is reported, counted from the reader, so it lands on the call that wrote the value.

• readRange(value, field, lo, hi, level) reads a number or {min, max}, and rangeArgs(min, max) packs the two arguments a range setter takes.
• readSize(value, fallbackSeq, level) reads a number, {min, max}, a NumberSequence or a keypoint list.
• asNumberSequence(value, fallback, field, level) and asColorSequence(value, fallback) read a curve.
• readBursts(bursts) normalizes a burst schedule; readDirection(dir) a direction.
• readNumber, readBoolean, readEnum, readVector and readTable read one value of their kind, and nameSet(names) builds the set readEnum checks against.

local Spec = require("@builtin::deprecated.deprecatedParticles.engine.spec")
local lo, hi = Spec.readRange({ 1, 3 }, "lifetime", 1, 1, 2)
print(lo, hi) -- 1 3