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use crate::error::pretty_error_desc;
use super::syntax::{SyntaxElement, SyntaxKind, SyntaxNode, SyntaxToken};
use text_size::TextRange;
#[derive(Debug, PartialEq)]
pub struct AstError {
pub msg: String,
pub span: TextRange,
}
impl AstError {
pub fn new(msg: String, span: TextRange) -> Self {
AstError { msg, span }
}
pub fn pretty_desc(&self, source: &str) -> String {
pretty_error_desc(source, self.span, &self.msg)
}
}
#[derive(Debug)]
pub struct Root(SyntaxNode);
impl Root {
pub fn cast(node: SyntaxNode) -> Option<Self> {
if node.kind() == SyntaxKind::Root {
Some(Self(node))
} else {
None
}
}
pub fn children(&self) -> impl Iterator<Item = Expr> {
self.0.children().filter_map(Expr::cast)
}
pub fn span(&self) -> TextRange {
self.0.text_range()
}
}
#[derive(Debug)]
pub struct Ident(SyntaxNode);
impl Ident {
pub fn name(&self) -> Result<SyntaxToken, AstError> {
self.0
.children_with_tokens()
.filter_map(SyntaxElement::into_token)
.find(|token| token.kind() == SyntaxKind::Ident)
.ok_or_else(|| AstError::new(format!("Empty Ident.name in: {:?}", self.0), self.span()))
}
pub fn span(&self) -> TextRange {
self.0.text_range()
}
}
#[allow(clippy::enum_variant_names)]
#[derive(Debug)]
pub enum Expr {
Ident(Ident),
BinaryExpr(BinaryExpr),
Literal(Literal),
}
impl Expr {
pub fn cast(node: SyntaxNode) -> Option<Self> {
let result = match node.kind() {
SyntaxKind::Ident => Self::Ident(Ident(node)),
SyntaxKind::InfixExpr => Self::BinaryExpr(BinaryExpr(node)),
SyntaxKind::IntNumber => Self::Literal(Literal(node)),
SyntaxKind::LongNumber => Self::Literal(Literal(node)),
_ => return None,
};
Some(result)
}
}
#[derive(Debug)]
pub struct BinaryExpr(SyntaxNode);
impl BinaryExpr {
pub fn lhs(&self) -> Result<Expr, AstError> {
self.0.children().find_map(Expr::cast).ok_or_else(|| {
AstError::new(
format!("Cannot find lhs in {:?}", self.0.children()),
self.0.text_range(),
)
})
}
pub fn rhs(&self) -> Result<Expr, AstError> {
self.0
.children()
.filter_map(Expr::cast)
.nth(1)
.ok_or_else(|| {
AstError::new(
format!("Cannot find rhs in {:?}", self.0.children()),
self.0.text_range(),
)
})
}
pub fn op(&self) -> Result<SyntaxToken, AstError> {
self.0
.children_with_tokens()
.filter_map(SyntaxElement::into_token)
.find(|token| {
matches!(
token.kind(),
SyntaxKind::Plus
| SyntaxKind::Minus
| SyntaxKind::Star
| SyntaxKind::Slash
| SyntaxKind::And,
)
})
.ok_or_else(|| {
AstError::new(
format!("Cannot find bin op in {:?}", self.0),
self.0.text_range(),
)
})
}
pub fn span(&self) -> TextRange {
self.0.text_range()
}
}
#[derive(Debug)]
pub enum LiteralValue {
Int(i32),
Long(i64),
}
#[derive(Debug)]
pub struct Literal(SyntaxNode);
impl Literal {
pub fn parse(&self) -> Result<LiteralValue, AstError> {
let text = self.0.first_token().unwrap().text().to_string();
if text.ends_with('L') {
text.strip_suffix('L')
.unwrap()
.parse()
.ok()
.map(LiteralValue::Long)
} else {
text.parse().ok().map(LiteralValue::Int)
}
.ok_or_else(|| {
AstError::new(
format!("Failed to parse Literal from: {:?}", self.0),
self.span(),
)
})
}
pub fn span(&self) -> TextRange {
self.0.text_range()
}
}
