Logic in Bitbybit

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bitbybit.logic works with booleans, the values true and false, and with decisions made from them: "is this number greater than 10?", "should this item of the pattern get a hole?".

Single booleans

• boolean passes a true or false through unchanged, so a value can be set once in Rete or Blockly, named and reused.
• not flips a boolean, and notList flips every boolean in a list.

Comparing values

compare compares first with second and gives a boolean. operator picks the comparison:

• <, <=, > and >=;
• == and !=, which convert types first, so 5 == "5" is true;
• === and !==, which do not, so 5 === "5" is false.

Patterns from numbers

These turn a list of numbers into a list of booleans, one each, and are the usual way to decide which items of a pattern get a feature. Feed them distances, noise values or parameters along a curve, then pick items with bitbybit.lists.getByPattern.

• thresholdBooleanList gives true for a number below threshold and false at or above it.
• thresholdGapsBooleanList gives true for a number inside any of the ranges in gapThresholds, each [min, max] with both ends included.
• twoThresholdRandomGradient blends between two thresholds: below thresholdTotalTrue a number is always true, above thresholdTotalFalse always false, and in between the chance of true falls in nrLevels steps, so the pattern fades out instead of switching sharply.

thresholdBooleanList and thresholdGapsBooleanList take inverse, which flips every result.

randomBooleans draws length random booleans with no numbers as input, each true with probability trueThreshold. It and twoThresholdRandomGradient give a different result on every run.

Letting values through

• valueGate gives value when boolean is true and undefined when it is false. Use it to switch a branch of a script on or off.
• firstDefinedValueGate gives value1 when it is defined and value2 otherwise, so the second acts as a fallback. Only undefined counts as missing; null, 0 and false pass.

Every function

Function	What it does
boolean	Passes a boolean through unchanged, so a value can be given a name and reused.
compare	Compares two values with an operator: less, less or equal, greater, greater or equal, equal or not equal, in the loose (==) or strict (===) form.
firstDefinedValueGate	Picks the first of two values that is defined, so the second acts as a fallback.
not	Flips a boolean: true becomes false and false becomes true.
notList	Flips every boolean in a list.
randomBooleans	Draws a list of random booleans, each true with a given probability.
thresholdBooleanList	Turns numbers into booleans: true below the threshold, false at or above it.
thresholdGapsBooleanList	Turns numbers into booleans: true when the number falls inside any of the given ranges, false otherwise.
twoThresholdRandomGradient	Turns numbers into booleans with a random blend between two thresholds.
valueGate	Lets a value through when the boolean is true and gives undefined when it is false.