pochoir-template-engine 0.12.2

use pochoir_common::Spanned;
use std::result;
use thiserror::Error;

pub type Result<T> = result::Result<T, Spanned<Error>>;

#[derive(Error, Debug, PartialEq, Eq, Clone)]
pub enum Error {
    #[error("unknown statement {0:?}")]
    UnknownStatement(String),

    #[error("unbounded ranges are forbidden in `for` loops, if you want to index an array you can use its length as the end bound")]
    UnboundedRangeInForLoop,

    #[error("an `elif` statement cannot be used after an `else` statement, you probably forgot an `endif` statement")]
    ElifAfterElse,

    #[error(transparent)]
    LanguageError(#[from] pochoir_lang::Error),

    #[error(transparent)]
    StreamParserError(#[from] pochoir_common::Error),
}

pub(crate) trait AutoError<T>
where
    Self: Sized,
{
    fn auto_error(self) -> T;
}

pub(crate) trait AutoErrorOffset<T>
where
    Self: Sized,
{
    fn auto_error_offset(self, file_offset: usize) -> T;
}

impl<T> AutoErrorOffset<result::Result<T, Spanned<Error>>>
    for result::Result<T, Spanned<pochoir_common::Error>>
{
    fn auto_error_offset(self, file_offset: usize) -> result::Result<T, Spanned<Error>> {
        self.map_err(|e| {
            let span = e.span().clone();
            e.map_spanned(Error::StreamParserError)
                .with_span(span.start + file_offset..span.end + file_offset)
        })
    }
}

impl<T> AutoError<result::Result<T, Spanned<Error>>>
    for result::Result<T, Spanned<pochoir_lang::Error>>
{
    fn auto_error(self) -> result::Result<T, Spanned<Error>> {
        self.map_err(|e| e.map_spanned(Error::LanguageError))
    }
}