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use crate::core::*;
use crate::kw;
use crate::parser::{Parse, Parser, Result};
use crate::token::{Id, NameAnnotation, Span};
/// A WebAssembly function to be inserted into a module.
///
/// This is a member of both the function and code sections.
#[derive(Debug)]
pub struct Func<'a> {
/// Where this `func` was defined.
pub span: Span,
/// An identifier that this function is resolved with (optionally) for name
/// resolution.
pub id: Option<Id<'a>>,
/// An optional name for this function stored in the custom `name` section.
pub name: Option<NameAnnotation<'a>>,
/// If present, inline export annotations which indicate names this
/// definition should be exported under.
pub exports: InlineExport<'a>,
/// What kind of function this is, be it an inline-defined or imported
/// function.
pub kind: FuncKind<'a>,
/// The type that this function will have.
pub ty: TypeUse<'a, FunctionType<'a>>,
}
/// Possible ways to define a function in the text format.
#[derive(Debug)]
pub enum FuncKind<'a> {
/// A function which is actually defined as an import, such as:
///
/// ```text
/// (func (type 3) (import "foo" "bar"))
/// ```
Import(InlineImport<'a>),
/// Almost all functions, those defined inline in a wasm module.
Inline {
/// The list of locals, if any, for this function.
locals: Box<[Local<'a>]>,
/// The instructions of the function.
expression: Expression<'a>,
},
}
impl<'a> Parse<'a> for Func<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
let span = parser.parse::<kw::func>()?.0;
let id = parser.parse()?;
let name = parser.parse()?;
let exports = parser.parse()?;
let (ty, kind) = if let Some(import) = parser.parse()? {
(parser.parse()?, FuncKind::Import(import))
} else {
let ty = parser.parse()?;
let locals = Local::parse_remainder(parser)?.into();
(
ty,
FuncKind::Inline {
locals,
expression: parser.parse()?,
},
)
};
Ok(Func {
span,
id,
name,
exports,
ty,
kind,
})
}
}
/// A local for a `func` or `let` instruction.
///
/// Each local has an optional identifier for name resolution, an optional name
/// for the custom `name` section, and a value type.
#[derive(Debug)]
pub struct Local<'a> {
/// An identifier that this local is resolved with (optionally) for name
/// resolution.
pub id: Option<Id<'a>>,
/// An optional name for this local stored in the custom `name` section.
pub name: Option<NameAnnotation<'a>>,
/// The value type of this local.
pub ty: ValType<'a>,
}
/// Parser for `local` instruction.
///
/// A single `local` instruction can generate multiple locals, hence this parser
pub struct LocalParser<'a> {
/// All the locals associated with this `local` instruction.
pub locals: Vec<Local<'a>>,
}
impl<'a> Parse<'a> for LocalParser<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
let mut locals = Vec::new();
parser.parse::<kw::local>()?;
if !parser.is_empty() {
let id: Option<_> = parser.parse()?;
let name: Option<_> = parser.parse()?;
let ty = parser.parse()?;
let parse_more = id.is_none() && name.is_none();
locals.push(Local { id, name, ty });
while parse_more && !parser.is_empty() {
locals.push(Local {
id: None,
name: None,
ty: parser.parse()?,
});
}
}
Ok(LocalParser { locals })
}
}
impl<'a> Local<'a> {
pub(crate) fn parse_remainder(parser: Parser<'a>) -> Result<Vec<Local<'a>>> {
let mut locals = Vec::new();
while parser.peek2::<kw::local>()? {
parser.parens(|p| {
locals.extend(p.parse::<LocalParser>()?.locals);
Ok(())
})?;
}
Ok(locals)
}
}