Variables

SET MUTATIONPOINT · clone · mutationcount · mutationpointx · mutationpointy

SET MUTATIONPOINT

Move one point of a shape, or add one past its end. This authors the shape, so a behavior driving it ends.

SET MUTATIONPOINT shape, index, at
set_mutationpoint(shape, index, at)

Parameters

• shape AS ARRAY - The shape: a MUTATION.
• index AS NUMBER - Which point, from 0.
• at AS COORDINATE - Where it goes: (x, y).

Example

SCREEN 320, 240
triangle = MUTATION((0, 0), (50, 0), (25, 43))
SET MUTATIONPOINT triangle, 2, (25, 30)
PRINT mutationpointx(triangle, 2), mutationpointy(triangle, 2)

Notes

It’s also the function set_mutationpoint, for when you want what it gives back.

clone

Returns a deep, independent copy of a value. Crash BASIC arrays and objects are reference types: ‘b = a’ makes b an ALIAS of a (they share storage), so mutating one is seen through the other. CLONE(a) breaks that link, recursively duplicating nested arrays and objects so later mutations never bleed across. For scalars (Integer/Float/String) there is no shared storage, so CLONE just returns an equal value.

clone(value)

Parameters

• value - Any value. Arrays and Objects are deep-copied (recursively); scalars pass through unchanged.

Example

SCREEN 320, 240
original = {hp: 10, items: ["key"]}
copy = clone(original)
PUSH copy.items, "map"
PRINT LEN(original.items), LEN(copy.items)

mutationcount

Returns the number of points in a MUTATION variable. Returns 0 if the variable is not a mutation or is empty. Reading is non-destructive: a mutation driven by a behavior can be read as often as you like and keeps running. It is WRITING it (SET MUTATIONPOINT, re-assignment) that ends the behavior.

mutationcount(mutation)

Parameters

• mutation - MUTATION variable or variable name

Example

SCREEN 320, 240
shape = MUTATION((0, 0), (10, 0), (5, 8))
PRINT mutationcount(shape)

mutationpointx

Returns the X coordinate of a point in a MUTATION variable at the specified index. Returns 0 if the index is out of bounds or the variable is not a mutation. Reading is non-destructive: a mutation driven by a behavior can be read as often as you like and keeps running. It is WRITING it (SET MUTATIONPOINT, re-assignment) that ends the behavior.

mutationpointx(mutation, index)

Parameters

• mutation - MUTATION variable or variable name
• index - Zero-based index of the point

Example

SCREEN 320, 240
shape = MUTATION((0, 0), (10, 0), (5, 8))
FOR i = 0 ... mutationcount(shape) - 1
    PRINT mutationpointx(shape, i)
END FOR
PRINT mutationpointx(shape, 99)

mutationpointy

Returns the Y coordinate of a point in a MUTATION variable at the specified index. Returns 0 if the index is out of bounds or the variable is not a mutation. Reading is non-destructive: a mutation driven by a behavior can be read as often as you like and keeps running. It is WRITING it (SET MUTATIONPOINT, re-assignment) that ends the behavior.

mutationpointy(mutation, index)

Parameters

• mutation - MUTATION variable or variable name
• index - Zero-based index of the point

Example

SCREEN 320, 240
shape = MUTATION((0, 0), (10, 0), (5, 8))
FOR i = 0 ... mutationcount(shape) - 1
    PRINT mutationpointy(shape, i)
END FOR