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Copy pathmodule.rs
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170 lines (154 loc) · 5.38 KB
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use super::contracts::parse_contract_def;
use super::types::{parse_struct_def, parse_type_def};
use crate::ast::{Module, ModuleStmt, SimpleImportName};
use crate::node::{Node, Span};
use crate::{Label, ParseFailed, ParseResult, Parser, TokenKind};
use semver::VersionReq;
/// Parse a [`Module`].
pub fn parse_module(par: &mut Parser) -> ParseResult<Node<Module>> {
let mut body = vec![];
loop {
match par.peek() {
Some(TokenKind::Newline) => par.expect_newline("module")?,
Some(TokenKind::Dedent) => {
par.next()?;
break;
}
None => break,
Some(_) => {
let stmt = parse_module_stmt(par)?;
body.push(stmt);
}
}
}
let span = if body.is_empty() {
Span::zero()
} else {
body.first().unwrap().span + body.last()
};
Ok(Node::new(Module { body }, span))
}
/// Parse a [`ModuleStmt`].
pub fn parse_module_stmt(par: &mut Parser) -> ParseResult<Node<ModuleStmt>> {
match par.peek_or_err()? {
TokenKind::Pragma => parse_pragma(par),
TokenKind::Import => parse_simple_import(par),
TokenKind::Name if par.peeked_text() == "from" => parse_from_import(par),
TokenKind::Contract => parse_contract_def(par),
TokenKind::Struct => parse_struct_def(par),
TokenKind::Type => parse_type_def(par),
TokenKind::Event => todo!("module-level event def"),
_ => {
let tok = par.next()?;
par.unexpected_token_error(
tok.span,
"failed to parse module",
vec!["Note: expected import, contract, struct, type, or event".into()],
);
Err(ParseFailed)
}
}
}
/// Parse an `import` statement. This does not yet support paths, just module
/// names. Note that `from x import y` style imports are handled in
/// [`parse_from_import`].
/// # Panics
/// Panics if the next token isn't `import`.
pub fn parse_simple_import(par: &mut Parser) -> ParseResult<Node<ModuleStmt>> {
let import_tok = par.assert(TokenKind::Import);
// TODO: only handles `import foo, bar as baz`
let mut names = vec![];
loop {
let name =
par.expect_with_notes(TokenKind::Name, "failed to parse import statement", || {
vec![
"Note: `import` must be followed by a module name or path".into(),
"Example: `import mymodule".into(),
]
})?;
let alias = if par.peek() == Some(TokenKind::As) {
par.next()?;
let tok = par.expect(TokenKind::Name, "failed to parse import statement")?;
Some(tok.into())
} else {
None
};
let span = name.span + alias.as_ref();
names.push(Node::new(
SimpleImportName {
path: vec![Node::new(name.text.to_string(), name.span)],
alias,
},
span,
));
match par.peek() {
Some(TokenKind::Comma) => {
par.next()?;
continue;
}
Some(TokenKind::Newline) | None => break,
Some(_) => {
let tok = par.next()?;
par.unexpected_token_error(tok.span, "failed to parse `import` statement", vec![]);
return Err(ParseFailed);
}
}
}
let span = import_tok.span + names.last();
Ok(Node::new(ModuleStmt::SimpleImport { names }, span))
}
/// Parse a `from x import y` style import statement.
/// # Panics
/// Always panics. Unimplemented.
pub fn parse_from_import(par: &mut Parser) -> ParseResult<Node<ModuleStmt>> {
let tok = par.assert(TokenKind::Name);
assert_eq!(tok.text, "from");
todo!("parse from .. import (not supported in rest of compiler yet)")
}
/// Parse a `pragma <version-requirement>` statement.
pub fn parse_pragma(par: &mut Parser) -> ParseResult<Node<ModuleStmt>> {
let tok = par.assert(TokenKind::Pragma);
assert_eq!(tok.text, "pragma");
let mut version_string = String::new();
let mut tokens = vec![];
loop {
match par.peek() {
Some(TokenKind::Newline) => break,
None => break,
_ => {
let tok = par.next()?;
version_string.push_str(tok.text);
tokens.push(tok);
}
}
}
let version_requirement_span = match (tokens.first(), tokens.last()) {
(Some(first), Some(last)) => first.span + last.span,
_ => {
par.error(
tok.span,
"failed to parse pragma statement: missing version requirement",
);
return Err(ParseFailed);
}
};
match VersionReq::parse(&version_string) {
Ok(_) => Ok(Node::new(
ModuleStmt::Pragma {
version_requirement: Node::new(version_string, version_requirement_span),
},
tok.span + version_requirement_span,
)),
Err(err) => {
par.fancy_error(
format!("failed to parse pragma statement: {}", err),
vec![Label::primary(
version_requirement_span,
"Invalid version requirement",
)],
vec!["Example: `^0.5.0`".into()],
);
Err(ParseFailed)
}
}
}