Documentation
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Overview ¶
Package windowparams is the one reading of a window slot's configuration, shared by the window engine (internal/processing and its window factories) and predict (internal/descriptor) so both refuse the same request with the same code and the same rule sentence. It decides what a slot MEANS and never computes a value.
The rules, in the order Check judges them:
- order_by needs at least one key — except WIN_SHARE / WIN_LIFT, whose own reading (internal/shareparams) needs it only when cumulative — and every key names a field;
- field is required on every value-bearing operator (FieldRequired) and refused on the order-only ones (FieldForbidden: row number, rank, dense rank read no value);
- frame is refused on the operators that read none (FrameRejected), required on the ones that do (FrameRequired); a given frame is mode "rows", its bounds are >= 0, and a moving average bounds both ends;
- the operator's params (offset, periods, the EWMA smoothing factor, the share / lift slot).
Every refusal is PULSE_WINDOW_INVALID on both sides: predict prefixes "window[i] (TYPE): ", the engine "TYPE: ". Predict reports every refusal Check returns; the engine raises the first.
Window types this package does not table (an embedder's extension window) are judged on the type-neutral rules only: order_by, its keys, and a given frame's mode and bounds.
Leaf: stdlib + the public errors / types packages + paramread and the two operator-specific leaves (ewmaparams, shareparams).
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FieldForbidden ¶
func FieldForbidden(t types.WindowType) bool
FieldForbidden reports whether a window of type t refuses a field.
func FieldRequired ¶
func FieldRequired(t types.WindowType) bool
FieldRequired reports whether a window of type t reads a value field (and so refuses a slot without one).
func FrameRejected ¶
func FrameRejected(t types.WindowType) bool
FrameRejected reports whether a window of type t with a frame is refused (WIN_SHARE / WIN_LIFT included: their reading refuses it).
func FrameRequired ¶
func FrameRequired(t types.WindowType) bool
FrameRequired reports whether a window of type t without a frame is refused.
Types ¶
type LagSpec ¶
type LagSpec struct {
// Offset is how many rows back (lag) or forward (lead); default 1.
Offset int
// HasDefault reports a non-null params.default; Default is its value,
// emitted where the offset falls outside the partition.
HasDefault bool
Default any
}
LagSpec is the resolved meaning of a WIN_LAG / WIN_LEAD slot's params.
type Refusal ¶
type Refusal struct {
Op types.WindowType
Message string
Details map[string]any
}
Refusal is one violated rule: Message is the operator-neutral sentence (callers prefix their own context) and Details the offending values.
func Check ¶
Check returns every rule w breaks, in judging order; nil for a valid slot. A nil w is valid (the engine skips it).
func (*Refusal) Coded ¶
func (r *Refusal) Coded() *errors.CodedError
Coded returns the refusal as the engine raises it: PULSE_WINDOW_INVALID, prefixed with the operator name.
Source Files