60 lines
1.6 KiB
Go
60 lines
1.6 KiB
Go
package registry
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import (
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"fmt"
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"git.maximhutz.com/max/lambda/pkg/codec"
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)
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// A Conversion is a type-erased transformation from one representation to
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// another. It operates on Expr values, hiding the underlying representation
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// types.
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type Conversion interface {
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// InType returns the name of the source representation.
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InType() string
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// OutType returns the name of the target representation.
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OutType() string
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// Run applies the conversion to the given expression. Returns an error if
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// the expression's data does not match the expected source type.
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Run(Expr) (Expr, error)
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}
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// A registeredConversion adapts a typed codec.Conversion[T, U] into the
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// type-erased Conversion interface. It extracts the underlying T from an Expr,
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// applies the conversion, and wraps the result as a new Expr.
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type registeredConversion[T, U any] struct {
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conversion codec.Conversion[T, U]
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inType, outType string
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}
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func (c registeredConversion[T, U]) Run(expr Expr) (Expr, error) {
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t, ok := expr.Data().(T)
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if !ok {
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return nil, fmt.Errorf("could not parse '%v' as '%s'", t, c.inType)
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}
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u, err := c.conversion(t)
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if err != nil {
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return nil, err
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}
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return NewExpr(c.outType, u), nil
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}
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func (c registeredConversion[T, U]) InType() string { return c.inType }
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func (c registeredConversion[T, U]) OutType() string { return c.outType }
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// RegisterConversion registers a typed conversion function between two
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// representations.
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func RegisterConversion[T, U any](
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registry *Registry,
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conversion codec.Conversion[T, U],
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inType, outType string,
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) error {
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registry.converter.Add(registeredConversion[T, U]{conversion, inType, outType})
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return nil
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}
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