92 lines
1.7 KiB
Go
92 lines
1.7 KiB
Go
package rfc8259naturalnumber
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import (
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"io"
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"sourcecode.social/reiver/go-opt"
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"sourcecode.social/reiver/go-rfc8259/errors"
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"sourcecode.social/reiver/go-rfc8259/wholenumber"
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)
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// Parse tries to parse a JSON natural-number literal.
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// If it succeeds, then it return nil, and sets ‘dst’ to the parsed value.
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// If it failed, it returns an error.
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//
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// Example usage:
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//
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// var rs io.RuneScaner
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//
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// // ...
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//
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// var value rfc8259naturalnumber.NaturalNumber
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// err := rfc8259naturalnumber.Parse(rs, &value)
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//
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// if nil != err {
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// return err
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// }
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//
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// fmt.Printf("value = %#v\n", value)
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func Parse(runescanner io.RuneScanner, dst *NaturalNumber) error {
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if nil == runescanner {
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return rfc8259errors.ErrNilRuneScanner
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}
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if nil == dst {
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return rfc8259errors.ErrNilDestination
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}
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var r rune
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{
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var err error
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r, _, err = runescanner.ReadRune()
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if nil != err {
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if io.EOF == err {
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return rfc8259errors.ErrUnexpectedEndOfFile
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}
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return rfc8259errors.ErrProblemReadingRune(err)
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}
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}
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var minusPart opt.Optional[rune]
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var intPart rfc8259wholenumber.WholeNumber
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switch r {
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case '-':
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minusPart = opt.Something(r)
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default:
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if err := runescanner.UnreadRune(); nil != err {
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return rfc8259errors.ErrProblemUnreadingRune(err, r)
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}
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}
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err := rfc8259wholenumber.Parse(runescanner, &intPart)
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if nil != err {
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return err
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}
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var value string
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{
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var buffer [256]byte
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var p []byte = buffer[0:0]
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minusPart.WhenSomething(func(value rune){
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p = append(p, string(value)...)
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})
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intPart.WhenSomething(func(value string){
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p = append(p, value...)
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})
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if len(p) < 1 {
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}
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value = string(p)
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}
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*dst = Something(value)
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return nil
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}
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