43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
package token
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import (
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"fmt"
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"git.maximhutz.com/max/lambda/pkg/iterator"
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)
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// ParseRawToken consumes the next token from the iterator if its type matches
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// the expected type.
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// Returns an error if the iterator is exhausted or the token type does not
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// match.
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func ParseRawToken[T Type](i *iterator.Iterator[Token[T]], expected T) (*Token[T], error) {
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tok, err := i.Get()
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if err != nil {
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return nil, err
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}
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if tok.Type != expected {
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return nil, fmt.Errorf("expected token '%v', got '%v'", expected.Name(), tok.Value)
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}
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i.Forward()
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return &tok, nil
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}
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// ParseList repeatedly applies a parse function, collecting results into a
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// slice.
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// Stops when the parse function returns an error.
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// Returns an error if fewer than minimum results are collected.
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func ParseList[T Type, U any](i *iterator.Iterator[Token[T]], fn func(*iterator.Iterator[Token[T]]) (U, error), minimum int) ([]U, error) {
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results := []U{}
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for {
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if u, err := fn(i); err != nil {
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if len(results) < minimum {
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return nil, fmt.Errorf("expected at least '%v' items, got only '%v': %w", minimum, len(results), err)
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}
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return results, nil
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} else {
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results = append(results, u)
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}
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}
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}
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