Palette Inheritance

You already know that the main file’s palette overrides imported values. But sometimes you don’t want to replace an imported colour — you want to derive from it. The séance operator lets you do exactly that.

The Problem With Overriding

Say you have a shared palette:

shared/palette.yaml

palette:
  blue: oklch(0.5 0.2 210)
  teal: oklch(0.6 0.05 240)

And you’re building a muted variant. You could write:

muted.yaml

palette:
  blue: "#4a5568"
  teal: "#4a6065"

But now you’re managing two sets of hex codes and hoping they stay in sync. If the shared palette changes, your variant is wrong. You’re not describing a relationship — you’re describing a copy.

Summoning the Past Self

The séance operator (^) references the prior value of the same key — whatever was accumulated from imports before this definition ran.

muted.yaml

palette:
  blue: desaturate(^, 40)
  teal: desaturate(^, 40)

Now blue and teal are defined as relationships to the imported values. If the shared palette changes tomorrow, the muted variant recalculates automatically.

Syntax Variants

The séance operator comes in three forms, matching the variable reference styles:

Form	Syntax	Use when
Bare	^	Simple, unambiguous position
Parenthesised	^()	Adjacent to other parentheses
Braced	^{}	Adjacent to braces

All three mean the same thing. darken(^, 10), darken(^(), 10), and darken(^{}, 10) are identical.

A Real-World Variant

The grayscale-at-a-percentage use case is where this really shines:

shared/palette.yaml

  palette:
    blue:   oklch(0.5 0.2 210)
    teal:   oklch(0.6 0.05 240)
    green:  oklch(0.765 0.125 168)
    purple: oklch(0.641 0.21 328)
    red:    oklch(0.672 0.215 25)

grayscale-variant.yaml

config:
  name: "My Theme (Muted)"
  type: dark
  import:
    - ./shared/palette.yaml
    - ./shared/variables.yaml

palette:
  blue:   grayscale(^)
  teal:   grayscale(^)
  green:  grayscale(^)
  purple: grayscale(^)
  red:    grayscale(^)

Every semantic variable that references these palette entries (accent, scope.keyword, etc.) automatically resolves to the grayscale version. VS Code never sees the intermediate steps.

Chaining Across Multiple Imports

The séance operator chains through import layers. Each definition in the chain references the accumulated value to that point:

palette-base.yaml

palette:
  teal: oklch(0.6 0.05 240)   # → #65859b

palette-shift.yaml

palette:
  teal: darken(^, 5)          # → #5c7c92

palette-flip.yaml

palette:
  teal: complement(^())       # → #8e715a

my-theme.yaml

config:
  import:
    - ./palette-base.yaml
    - ./palette-shift.yaml
    - ./palette-flip.yaml

palette:
  teal: lighten(^, 10)        # → #a0826a

Each layer only needs to know “take whatever came before me and do this to it.” No knowledge of hex codes, no duplication, no manual synchronisation.

Debugging the Chain

The resolve command shows the full derivation trail:

npx @gesslar/sassy resolve -c palette.teal my-theme.yaml

palette.teal:

lighten(^(teal), 10)
^(teal)
   complement(^(teal))
   ^(teal)
      darken(^(teal), 5)
      ^(teal)
         oklch(0.6 0.05 240)
            ■ #65859b
      darken(#65859b, 5)
         ■ #5c7c92
   complement(#5c7c92)
      ■ #8e715a
lighten(#8e715a, 10)
   ■ #a0826a

Resolution: #a0826a

Each ^(teal) in the output represents one séance step, showing exactly what value was summoned and what was done with it.

Rules

• Palette only. The séance operator works in palette definitions. It does not apply in vars or theme.
• Leaf values only. It applies to string values. Object nodes have no prior value to reference.
• Requires a prior. If no imported file (or earlier import) has defined this key, ^ has nothing to summon and is left as a literal.