kosame_dsl 0.3.0

Macro-based Rust ORM focused on developer ergonomics
Documentation 
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use proc_macro2::{Span, TokenStream};
use quote::{ToTokens, quote};
use syn::{
    Ident, Token, parenthesized,
    parse::{Parse, ParseStream},
    spanned::Spanned,
    token::Paren,
};

use crate::{
    data_type::DataType,
    inferred_type::InferredType,
    keyword,
    pretty::{BreakMode, Delim, PrettyPrint, Printer},
    scopes::ScopeId,
};

use super::{Expr, Visit};

pub struct Cast {
    pub cast_kw: keyword::cast,
    pub paren: Paren,
    pub value: Box<Expr>,
    pub as_token: Token![as],
    pub data_type: DataType,
}

impl Cast {
    pub fn peek(input: ParseStream) -> bool {
        input.peek(keyword::cast)
    }

    #[must_use]
    pub fn infer_name(&self) -> Option<&Ident> {
        self.value.infer_name()
    }

    #[must_use]
    pub fn infer_type(&self, _scope_id: ScopeId) -> Option<InferredType<'_>> {
        // Difficulty detecting nullability
        // Some(InferredType::DataType(self.data_type.clone()))

        None
    }

    #[must_use]
    pub fn span(&self) -> Span {
        self.cast_kw
            .span
            .join(self.paren.span.span())
            .unwrap_or(self.cast_kw.span)
    }
}

pub fn visit_cast<'a>(visit: &mut (impl Visit<'a> + ?Sized), cast: &'a Cast) {
    visit.visit_expr(&cast.value);
}

impl Parse for Cast {
    fn parse(input: ParseStream) -> syn::Result<Self> {
        let content;
        Ok(Self {
            cast_kw: input.parse()?,
            paren: parenthesized!(content in input),
            value: content.parse()?,
            as_token: content.parse()?,
            data_type: content.parse()?,
        })
    }
}

impl ToTokens for Cast {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let value = &self.value;
        let data_type = &self.data_type.name.to_string();
        quote! {
            ::kosame::repr::expr::Cast::new(&#value, #data_type)
        }
        .to_tokens(tokens);
    }
}

impl PrettyPrint for Cast {
    fn pretty_print(&self, printer: &mut Printer) {
        self.cast_kw.pretty_print(printer);
        self.paren
            .pretty_print(printer, Some(BreakMode::Inconsistent), |printer| {
                self.value.pretty_print(printer);
                printer.scan_break();
                " ".pretty_print(printer);
                self.as_token.pretty_print(printer);
                " ".pretty_print(printer);
                self.data_type.pretty_print(printer);
            });
    }
}