59 lines
1.7 KiB
Go
59 lines
1.7 KiB
Go
package registry
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import (
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"fmt"
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"git.maximhutz.com/max/lambda/pkg/engine"
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)
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// An Engine is a type-erased evaluation engine that can load an expression
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// into a runnable Process.
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type Engine interface {
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// Load prepares an expression for evaluation, returning a Process. Returns
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// an error if the expression's data does not match the engine's expected
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// representation type.
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Load(Expr) (Process, error)
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// Name returns the name of this engine.
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Name() string
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// InType returns the name of the representation this engine operates on.
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InType() string
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}
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// A registeredEngine adapts a typed engine.Engine[T] into the type-erased
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// Engine interface. It extracts the underlying T from an Expr before passing it
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// to the engine.
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type registeredEngine[T any] struct {
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engine engine.Engine[T]
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name string
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inType string
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}
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func (e registeredEngine[T]) InType() string { return e.inType }
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func (e registeredEngine[T]) Name() string { return e.name }
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func (e registeredEngine[T]) Load(expr Expr) (Process, error) {
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t, ok := expr.Data().(T)
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if !ok {
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return nil, fmt.Errorf("incorrect format '%s' for engine '%s'", expr.Repr(), e.inType)
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}
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process, err := e.engine(t)
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if err != nil {
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return nil, err
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}
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return registeredProcess[T]{process, e.inType}, nil
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}
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// RegisterEngine registers a typed engine under the given name. Returns an
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// error if an engine with that name is already registered.
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func RegisterEngine[T any](registry *Registry, e engine.Engine[T], name, inType string) error {
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if _, ok := registry.engines[name]; ok {
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return fmt.Errorf("engine '%s' already registered", name)
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}
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registry.engines[name] = ®isteredEngine[T]{e, name, inType}
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return nil
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}
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