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Copy pathfunctions.rs
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431 lines (400 loc) · 13.8 KB
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use super::expressions::{parse_call_args, parse_expr};
use super::types::parse_type_desc;
use crate::ast::{BinOperator, ContractStmt, Expr, FuncDefArg, FuncStmt, VarDeclTarget};
use crate::lexer::TokenKind;
use crate::node::{Node, Span};
use crate::{Label, ParseFailed, ParseResult, Parser};
/// Parse a function definition. The optional `pub` qualifier must be parsed by
/// the caller, and passed in.
///
/// # Panics
/// Panics if the next token isn't `def`.
pub fn parse_fn_def(par: &mut Parser, pub_qual: Option<Span>) -> ParseResult<Node<ContractStmt>> {
let def_tok = par.assert(TokenKind::Def);
let name = par.expect(TokenKind::Name, "failed to parse function definition")?;
let mut span = def_tok.span + pub_qual + name.span;
let args = match par.peek_or_err()? {
TokenKind::ParenOpen => {
let node = parse_fn_param_list(par)?;
span += node.span;
node.kind
}
TokenKind::Colon | TokenKind::Arrow => {
par.fancy_error(
"function definition requires a list of parameters",
vec![Label::primary(
name.span,
"function name must be followed by `(`",
)],
vec![
format!(
"Note: if the function `{}` takes no parameters, use an empty set of parentheses.",
name.text
),
format!("Example: def {}()", name.text),
"Note: each parameter must have a name and a type.".into(),
format!("Example: def {}(my_value: u256, x: bool)", name.text),
],
);
vec![]
}
_ => {
let tok = par.next()?;
par.unexpected_token_error(
tok.span,
"failed to parse function definition",
vec![
"function name must be followed by a list of parameters".into(),
"Example: `def foo(x: address, y: u256)` or `def f()`".into(),
],
);
return Err(ParseFailed);
}
};
let return_type = if par.peek() == Some(TokenKind::Arrow) {
par.next()?;
Some(parse_type_desc(par)?)
} else {
None
};
span += return_type.as_ref();
// TODO: allow multi-line return type? `def f()\n ->\n u8`
// TODO: allow single-line fn defs?
par.enter_block(span, "function definition")?;
let body = parse_block_stmts(par)?;
span += body.last();
Ok(Node::new(
ContractStmt::FuncDef {
is_pub: pub_qual.is_some(),
name: name.into(),
args,
return_type,
body,
},
span,
))
}
fn parse_fn_param_list(par: &mut Parser) -> ParseResult<Node<Vec<Node<FuncDefArg>>>> {
let mut span = par.assert(TokenKind::ParenOpen).span;
let mut params = vec![];
loop {
match par.peek_or_err()? {
TokenKind::ParenClose => {
span += par.next()?.span;
break;
}
TokenKind::Name => {
let name = par.next()?;
par.expect_with_notes(
TokenKind::Colon,
"failed to parse function parameter",
|| {
vec![
"Note: parameter name must be followed by a colon and a type description"
.into(),
format!("Example: `{}: u256`", name.text),
]
},
)?;
let typ = parse_type_desc(par)?;
let param_span = name.span + typ.span;
params.push(Node::new(
FuncDefArg {
name: Node::new(name.text.into(), name.span),
typ,
},
param_span,
));
if par.peek() == Some(TokenKind::Comma) {
par.next()?;
} else {
span += par
.expect(
TokenKind::ParenClose,
"unexpected token while parsing function parameter list",
)?
.span;
break;
}
}
_ => {
let tok = par.next()?;
par.unexpected_token_error(
tok.span,
"failed to parse function parameter list",
vec![],
);
return Err(ParseFailed);
}
}
}
Ok(Node::new(params, span))
}
/// Parse (function) statements until a block dedent or end-of-file is reached.
fn parse_block_stmts(par: &mut Parser) -> ParseResult<Vec<Node<FuncStmt>>> {
let mut body = vec![];
loop {
match par.peek() {
None => break,
Some(TokenKind::Dedent) => {
par.next()?;
break;
}
Some(_) => body.push(parse_stmt(par)?),
}
}
Ok(body)
}
fn aug_assign_op(tk: TokenKind) -> Option<BinOperator> {
use BinOperator::*;
use TokenKind::*;
let op = match tk {
PlusEq => Add,
MinusEq => Sub,
StarEq => Mult,
SlashEq => Div,
PercentEq => Mod,
StarStarEq => Pow,
LtLtEq => LShift,
GtGtEq => RShift,
PipeEq => BitOr,
HatEq => BitXor,
AmperEq => BitAnd,
_ => return None,
};
Some(op)
}
/// Parse a `continue`, `break`, `pass`, or `revert` statement.
///
/// # Panics
/// Panics if the next token isn't one of the above.
pub fn parse_single_word_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let tok = par.next()?;
par.expect_newline(tok.kind.symbol_str().unwrap())?;
let stmt = match tok.kind {
TokenKind::Continue => FuncStmt::Continue,
TokenKind::Break => FuncStmt::Break,
TokenKind::Pass => FuncStmt::Pass,
TokenKind::Revert => FuncStmt::Revert,
_ => panic!(),
};
Ok(Node::new(stmt, tok.span))
}
/// Parse a function-level statement.
pub fn parse_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
use TokenKind::*;
// rule: stmt parsing fns eat the trailing separator (newline, semi, eof)
match par.peek_or_err()? {
For => parse_for_stmt(par),
If => parse_if_stmt(par),
While => parse_while_stmt(par),
Return => parse_return_stmt(par),
Assert => parse_assert_stmt(par),
Continue | Break | Pass | Revert => parse_single_word_stmt(par),
Emit => parse_emit_statement(par),
_ => parse_expr_stmt(par),
}
}
/// Parse a (function) statement that begins with an expression. This might be
/// a `VarDecl`, `Assign`, or an expression.
fn parse_expr_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
use TokenKind::*;
let expr = parse_expr(par)?;
let node = match par.peek() {
None | Some(Newline) => {
let span = expr.span;
Node::new(FuncStmt::Expr { value: expr }, span)
}
Some(Colon) => {
par.next()?;
let target = expr_to_vardecl_target(par, expr)?;
let typ = parse_type_desc(par)?;
let value = if par.peek() == Some(Eq) {
par.next()?;
Some(parse_expr(par)?)
} else {
None
};
let span = target.span + typ.span + value.as_ref();
Node::new(FuncStmt::VarDecl { target, typ, value }, span)
}
Some(Eq) => {
par.next()?;
let value = parse_expr(par)?;
let span = expr.span + value.span;
// TODO: should `x = y = z` be allowed?
Node::new(
FuncStmt::Assign {
target: expr,
value,
},
span,
)
}
Some(tk) => {
if let Some(op) = aug_assign_op(tk) {
let op_tok = par.next()?;
let value = parse_expr(par)?;
let span = expr.span + value.span;
Node::new(
FuncStmt::AugAssign {
target: expr,
op: Node::new(op, op_tok.span),
value,
},
span,
)
} else {
let tok = par.next()?;
par.unexpected_token_error(tok.span, "invalid syntax in function body", vec![]);
return Err(ParseFailed);
}
}
};
par.expect_newline("statement")?;
Ok(node)
}
fn expr_to_vardecl_target(par: &mut Parser, expr: Node<Expr>) -> ParseResult<Node<VarDeclTarget>> {
match expr.kind {
Expr::Name(name) => Ok(Node::new(VarDeclTarget::Name(name), expr.span)),
Expr::Tuple { elts } if !elts.is_empty() => Ok(Node::new(
VarDeclTarget::Tuple(
elts.into_iter()
.map(|elt| expr_to_vardecl_target(par, elt))
.collect::<ParseResult<Vec<_>>>()?,
),
expr.span,
)),
_ => {
par.fancy_error(
"failed to parse variable declaration",
vec![Label::primary(
expr.span,
"invalid variable declaration target",
)],
vec![
"The left side of a variable declaration can be either a name\nor a non-empty tuple."
.into(),
],
);
Err(ParseFailed)
}
}
}
/// Parse an `if` statement, or an `elif` block.
///
/// # Panics
/// Panics if the next token isn't `if` or `elif`.
pub fn parse_if_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let if_tok = par.next()?;
assert!(matches!(if_tok.kind, TokenKind::If | TokenKind::Elif));
let test = parse_expr(par)?;
par.enter_block(if_tok.span + test.span, "`if` statement")?;
let body = parse_block_stmts(par)?;
let else_block = match par.peek() {
Some(TokenKind::Else) => {
let else_tok = par.next()?;
par.enter_block(else_tok.span, "`if` statement `else` branch")?;
parse_block_stmts(par)?
}
Some(TokenKind::Elif) => {
vec![parse_if_stmt(par)?]
}
_ => vec![],
};
let span = if_tok.span + test.span + body.last() + else_block.last();
Ok(Node::new(
FuncStmt::If {
test,
body,
or_else: else_block,
},
span,
))
}
/// Parse a `while` statement.
///
/// # Panics
/// Panics if the next token isn't `while`.
pub fn parse_while_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let while_tok = par.assert(TokenKind::While);
let test = parse_expr(par)?;
par.enter_block(while_tok.span + test.span, "`while` statement")?;
let body = parse_block_stmts(par)?;
let span = while_tok.span + test.span + body.last();
Ok(Node::new(FuncStmt::While { test, body }, span))
}
/// Parse a `for` statement.
///
/// # Panics
/// Panics if the next token isn't `for`.
pub fn parse_for_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let for_tok = par.assert(TokenKind::For);
let target = par
.expect(TokenKind::Name, "failed to parse `for` statement")?
.into();
par.expect(TokenKind::In, "failed to parse `for` statement")?;
let iter = parse_expr(par)?;
par.enter_block(for_tok.span + iter.span, "`for` statement")?;
let body = parse_block_stmts(par)?;
let span = for_tok.span + iter.span + body.last();
Ok(Node::new(FuncStmt::For { target, iter, body }, span))
}
/// Parse a `return` statement.
///
/// # Panics
/// Panics if the next token isn't `return`.
pub fn parse_return_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let ret = par.assert(TokenKind::Return);
let value = match par.peek() {
None | Some(TokenKind::Newline) => None,
Some(_) => Some(parse_expr(par)?),
};
par.expect_newline("return statement")?;
let span = ret.span + value.as_ref();
Ok(Node::new(FuncStmt::Return { value }, span))
}
/// Parse an `assert` statement.
///
/// # Panics
/// Panics if the next token isn't `assert`.
pub fn parse_assert_stmt(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let assert_tok = par.assert(TokenKind::Assert);
let test = parse_expr(par)?;
let msg = match par.peek() {
None | Some(TokenKind::Newline) => None,
Some(TokenKind::Comma) => {
par.next()?;
Some(parse_expr(par)?)
}
Some(_) => {
let tok = par.next()?;
par.unexpected_token_error(tok.span, "failed to parse `assert` statement", vec![]);
return Err(ParseFailed);
}
};
par.expect_newline("assert statement")?;
let span = assert_tok.span + test.span + msg.as_ref();
Ok(Node::new(FuncStmt::Assert { test, msg }, span))
}
/// Parse an `emit` statement
///
/// # Panics
/// Panics if the next token isn't `emit`
pub fn parse_emit_statement(par: &mut Parser) -> ParseResult<Node<FuncStmt>> {
let emit_tok = par.assert(TokenKind::Emit);
let event_name = par.expect(TokenKind::Name, "failed to parse emit statement")?;
if let Some(TokenKind::ParenOpen) = par.peek() {
let args = parse_call_args(par)?;
par.expect_newline("emit statement")?;
let span = emit_tok.span + args.span;
let name = Node::new(event_name.text.to_string(), event_name.span);
return Ok(Node::new(FuncStmt::Emit { name, args }, span));
} else {
par.expect(
TokenKind::ParenOpen,
"failed to parse event invocation parameter list",
)?;
}
Err(ParseFailed)
}