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Implement methods to go backwards and look backwards inside Scanner

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#395 2 comentarios 0 reacciones 0 asignados Ver en GitHub

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Evaluación

Dificultad
3/5
Tiempo estimado
1-2 días
Aptitud para principiantes
38/100
Tipo de issue
Nueva funcionalidad
Claridad
Bastante claro
Estado de actividad
Estancado
Stack tecnológico
java
Área
compilers

Línea de trabajo

Comienza en el punto de entrada de Scanner y compara el comportamiento existente de next y find descrito en el issue. Define equivalentes hacia atrás que actualicen la posición del scanner según lo solicitado, incluido el comportamiento de búsqueda acotada, y verifica que el caso de uso de análisis de image-link pueda obtener el rango esperado.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

enhancement

Is your feature request related to a problem? Please describe.
I'm trying to implement an InlineContentParser for images from a custom markdown spec from a certain website. Given I already parsed the opener, the spec requires me to look for the first whitespace character or end of text, then going backwards from there, look for the first ). Everything between the opener and ) is considered the image link.

This is a bit annoying to implement with the current limited set of methods Scanner has, and I also imagine the performance would be worse when instead of going backwards from the closer, you go forward from the opener via scanner.find(')') and perform an additional find to see if you just found the last ).

Describe the solution you'd like
I would like for there to be similar methods to next and find that would instead look back from the current Scanner position, i.e prev, and findPrev. Then I could just do the following (sorry that the code is in Kotlin as I don't regularly write Java, I hope the intent is clear):

val start = scanner.position()  // position after the opener has been parsed
scanner.find { char -> char.isWhitespace() } // scanner gets moved to first whitespace or very end if there is none
scanner.findPrev(')') // scanner gets moved backwards until the position is at ')'. Ideally there would also be an overload that takes a position until which it should move, so i could pass the `start` to it and it would early exit if it doesn't find one by then
val end = scanner.position() 
val imageLink = scanner.getSource(start, end).getContent()

Describe alternatives you've considered
As stated above I have considered iterating forward from the current position to find the next ) and check if there's another one to see if I'd found the last one.

Lenguaje dominante
Java
Estrellas
2.7k
Forks
337
Merge medio
15 d 9 h
PR fusionados (30 d)
1

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  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

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