Chunk Investigation

This page will outline the progress of #3086 to document how we currently use chunks to see if we are doing it "correctly."

Investigating DefinedQuantityDict

So I decided to take first pass with DefinedQuantityDict, since that's where this issue started, and I noticed the following.

Summary of DefinedQuantityDict

A DefinedQuantityDict is created by taking a ConceptChunk and adding the parts necessary to also make it a Quantity, which includes a symbol (that might depend on the stage), a space, and maybe a unit.

"Issues" with DQD currently:

ConceptChunks made only to be used in a DQD

Sometimes, as in Projectile (see below), we create a ConceptChunk that is only used in a DQD. What is the rationale for this? Couldn't we just define the ConceptChunk locally in the constructor for the DQD, or is there some reason (e.g., to support future changes that might need just the ConceptChunk for something else) that we define the ConceptChunk separately? I was able to migrate this specific example to just using a local ConceptChunk and it worked without a problem, although the code got a bit harder to read (which might be a valid enough reason for this method of building DQDs). (The concept is defined here and the DefinedQuantityDict is defined here).

-- Concepts.hs
launAngle :: ConceptChunk
launAngle = cc' launchAngleNC
  (foldlSent_ [phraseNP (the angle), S "between the", phrase launcher `S.and_` S "a straight line"
             `S.fromThe` phraseNP (launcher `toThe` target)])

-- Unitals.hs
import qualified Drasil.Projectile.Concepts as C (launAngle)

launAngle :: ConstrConcept
launAngle = constrained' (dqd' C.launAngle (autoStage lTheta) Real (Just radian)) [physc $ Bounded (Exc, exactDbl 0) (Exc, half $ sy pi_)] (sy pi_ $/ exactDbl 4)

"Projections" to DQDs

There is a constructor dqdWr, that takes a chunk with all the required information for a DQD and creates a corresponding DQD. It is called on the following chunks:

• In GamePhysics: unitSymbs, inputConstraints, and outputConstraints
• In NoPCM: concepts, constrained, tempW, watE, and surface
• In SSP: coords, inputs, xMaxExtSlip, xMaxEtrSlip, xMinExtSlip, xMinEtrSlip, yMaxSlip, yMinSlip, outputs, units, unitless, inputsWUncrtn, inputsNoUncrtn, constrained, and surface

In every one of these cases, its use is to combine quantities of different types into one list of DefinedQuantityDicts.

It is also used in drasil-lang in the following functions:

• In Chunk.Constrained: constrained', constrainedNRV', and cnstrw'
• In Chunk.UncertainQuantity: uq