WorkflowState R6 class

Mutable shared state passed between graph nodes. Each named channel has a default value and a reducer function that controls how updates are merged.

Value

A new WorkflowState object.

The current channel value.

Invisibly, self.

Invisibly, self.

Named list.

Invisibly, self.

Character vector.

The value of the output channel.

Invisibly, self.

Active bindings

schema

The raw schema list (read-only). Used by GraphRunner to reconstruct a fresh state on each $invoke() call.

Methods

Public methods

• WorkflowState$new()

• WorkflowState$get()

• WorkflowState$set()

• WorkflowState$update()

• WorkflowState$snapshot()

• WorkflowState$restore()

• WorkflowState$keys()

• WorkflowState$output()

• WorkflowState$set_output_channel()

• WorkflowState$print()

• WorkflowState$clone()

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Method new()

Create a new WorkflowState.

Usage

WorkflowState$new(schema)

Arguments

schema

Named list where each element is list(default = <value>, reducer = <function>). If reducer is omitted, reducer_last_n() with a window of 20 is used for list channels and reducer_overwrite() for all other channels.

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Method get()

Get the current value of a channel.

Usage

WorkflowState$get(key)

Arguments

key

Character. Channel name.

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Method set()

Set (apply reducer to) a single channel.

Usage

WorkflowState$set(key, value)

Arguments

key

Character. Channel name.

value

New value passed to the reducer.

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Method update()

Apply a named list of updates to the state.

Usage

WorkflowState$update(updates)

Arguments

updates

Named list. Keys starting with "." are reserved and silently ignored. Unknown keys raise an error (typo protection).

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Method snapshot()

Return a deep copy of the current state as a plain list.

Usage

WorkflowState$snapshot()

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Method restore()

Restore state from a snapshot.

Usage

WorkflowState$restore(snap)

Arguments

snap

Named list previously produced by $snapshot().

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Method keys()

Return the names of all channels.

Usage

WorkflowState$keys()

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Method output()

Return the primary output of the workflow.

Convenience wrapper around $get() for the channel nominated as the output channel when the graph was compiled. For workflows that accumulate a list (e.g. messages), returns the full list; use [[length(...)]] to extract the final entry.

Usage

WorkflowState$output()

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Method set_output_channel()

Set the output channel. Called internally by GraphRunner.

Usage

WorkflowState$set_output_channel(channel)

Arguments

channel

Character. Channel name.

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Method print()

Print a summary of the state.

Usage

WorkflowState$print(...)

Arguments

...

Ignored.

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Method clone()

The objects of this class are cloneable with this method.

Usage

WorkflowState$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.