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|
use super::*;
/// The arguments passed to a function.
#[derive(Debug, Clone, PartialEq)]
pub struct FuncArgs {
pub pos: Vec<Spanned<PosArg>>,
pub key: Vec<Spanned<KeyArg>>,
}
impl FuncArgs {
/// Create an empty collection of arguments.
pub fn new() -> FuncArgs {
FuncArgs {
pos: vec![],
key: vec![],
}
}
/// Add a positional argument.
pub fn add_pos(&mut self, arg: Spanned<PosArg>) {
self.pos.push(arg);
}
/// Add a keyword argument.
pub fn add_key(&mut self, arg: Spanned<KeyArg>) {
self.key.push(arg);
}
/// Force-extract the first positional argument.
pub fn get_pos<E: ExpressionKind>(&mut self) -> ParseResult<E> {
expect(self.get_pos_opt())
}
/// Extract the first positional argument.
pub fn get_pos_opt<E: ExpressionKind>(&mut self) -> ParseResult<Option<E>> {
Ok(if !self.pos.is_empty() {
let spanned = self.pos.remove(0);
Some(E::from_expr(spanned)?)
} else {
None
})
}
/// Iterator over positional arguments.
pub fn pos(&mut self) -> std::vec::IntoIter<Spanned<PosArg>> {
let vec = std::mem::replace(&mut self.pos, vec![]);
vec.into_iter()
}
/// Force-extract a keyword argument.
pub fn get_key<E: ExpressionKind>(&mut self, name: &str) -> ParseResult<E> {
expect(self.get_key_opt(name))
}
/// Extract a keyword argument.
pub fn get_key_opt<E: ExpressionKind>(&mut self, name: &str) -> ParseResult<Option<E>> {
Ok(if let Some(index) = self.key.iter().position(|arg| arg.v.key.v.0 == name) {
let value = self.key.swap_remove(index).v.value;
Some(E::from_expr(value)?)
} else {
None
})
}
/// Extract any keyword argument.
pub fn get_key_next(&mut self) -> Option<Spanned<KeyArg>> {
self.key.pop()
}
/// Iterator over all keyword arguments.
pub fn keys(&mut self) -> std::vec::IntoIter<Spanned<KeyArg>> {
let vec = std::mem::replace(&mut self.key, vec![]);
vec.into_iter()
}
/// Clear the argument lists.
pub fn clear(&mut self) {
self.pos.clear();
self.key.clear();
}
/// Whether both the positional and keyword argument lists are empty.
pub fn is_empty(&self) -> bool {
self.pos.is_empty() && self.key.is_empty()
}
}
/// Extract the option expression kind from the option or return an error.
fn expect<E: ExpressionKind>(opt: ParseResult<Option<E>>) -> ParseResult<E> {
match opt {
Ok(Some(spanned)) => Ok(spanned),
Ok(None) => error!("expected {}", E::NAME),
Err(e) => Err(e),
}
}
/// A positional argument passed to a function.
pub type PosArg = Expression;
/// A keyword argument passed to a function.
#[derive(Debug, Clone, PartialEq)]
pub struct KeyArg {
pub key: Spanned<Ident>,
pub value: Spanned<Expression>,
}
/// Either a positional or keyword argument.
#[derive(Debug, Clone, PartialEq)]
pub enum DynArg {
Pos(Spanned<PosArg>),
Key(Spanned<KeyArg>),
}
/// An argument or return value.
#[derive(Clone, PartialEq)]
pub enum Expression {
Ident(Ident),
Str(String),
Num(f64),
Size(Size),
Bool(bool),
}
impl Display for Expression {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
use Expression::*;
match self {
Ident(i) => write!(f, "{}", i),
Str(s) => write!(f, "{:?}", s),
Num(n) => write!(f, "{}", n),
Size(s) => write!(f, "{}", s),
Bool(b) => write!(f, "{}", b),
}
}
}
debug_display!(Expression);
pub struct Tuple;
pub struct Object;
/// An identifier.
#[derive(Clone, PartialEq)]
pub struct Ident(pub String);
impl Ident {
pub fn new<S>(ident: S) -> Option<Ident> where S: AsRef<str> + Into<String> {
if is_identifier(ident.as_ref()) {
Some(Ident(ident.into()))
} else {
None
}
}
pub fn as_str(&self) -> &str {
self.0.as_str()
}
}
impl Display for Ident {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "{}", self.0)
}
}
debug_display!(Ident);
/// Kinds of expressions.
pub trait ExpressionKind: Sized {
const NAME: &'static str;
/// Create from expression.
fn from_expr(expr: Spanned<Expression>) -> ParseResult<Self>;
}
macro_rules! kind {
($type:ty, $name:expr, $($patterns:tt)*) => {
impl ExpressionKind for $type {
const NAME: &'static str = $name;
fn from_expr(expr: Spanned<Expression>) -> ParseResult<Self> {
#[allow(unreachable_patterns)]
Ok(match expr.v {
$($patterns)*,
_ => error!("expected {}", Self::NAME),
})
}
}
};
}
kind!(Expression, "expression", e => e);
kind!(Ident, "identifier", Expression::Ident(ident) => ident);
kind!(String, "string", Expression::Str(string) => string);
kind!(f64, "number", Expression::Num(num) => num);
kind!(bool, "boolean", Expression::Bool(boolean) => boolean);
kind!(Size, "size", Expression::Size(size) => size);
kind!(ScaleSize, "number or size",
Expression::Size(size) => ScaleSize::Absolute(size),
Expression::Num(scale) => ScaleSize::Scaled(scale as f32)
);
impl<T> ExpressionKind for Spanned<T> where T: ExpressionKind {
const NAME: &'static str = T::NAME;
fn from_expr(expr: Spanned<Expression>) -> ParseResult<Spanned<T>> {
let span = expr.span;
T::from_expr(expr)
.map(|v| Spanned::new(v, span))
}
}
impl<T> ExpressionKind for Option<T> where T: ExpressionKind {
const NAME: &'static str = T::NAME;
fn from_expr(expr: Spanned<Expression>) -> ParseResult<Option<T>> {
if let Expression::Ident(ident) = &expr.v {
match ident.as_str() {
"default" | "none" => return Ok(None),
_ => {},
}
}
T::from_expr(expr).map(|v| Some(v))
}
}
|
