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