AbleScript/ablescript
3
4
Fork 1
Code Issues Pull requests Projects Releases 7 Wiki Activity

Fix panic on arithmetic error

Browse source 
Divide by zero and add, subtract, or multiply with overflow are all
caught now and reported as an ArithmeticError, rather than causing the
interpreter to panic.
This commit is contained in:
Alex Bethel 2021-05-30 13:26:10 -05:00
parent acfd81ead2
commit 07195d4cf6
1 changed files with 35 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

49
src/interpret.rs
View file

@ -110,21 +110,42 @@ impl ExecEnv {
use Expr::*; use Expr::*;
use Value::*; use Value::*;
// NOTE(Alex): This is quite nasty, and should probably be // NOTE(Alex): This is really quite horrible. I think the only
// re-done using macros or something. // real way to clean it up would be to re-engineer the AST's
// representation to be more hierarchical: rather than having
// e.g. "Expr::Add" and "Expr::Subtract" each with a "left"
// and "right" struct member, have something like
// "Expr::Binary { oper: BinOp, left: Box<Expr>, right:
// Box<Expr> }". That way we could factor out a whole bunch of
// common code here.
//
// That work should probably wait for Ondra's new parser to
// come in, however.
Ok(match expr { Ok(match expr {
Add { left, right } => { Add { left, right } => Int(i32::try_from(self.eval_expr(left)?)?
Int(i32::try_from(self.eval_expr(left)?)? + i32::try_from(self.eval_expr(right)?)?) .checked_add(i32::try_from(self.eval_expr(right)?)?)
} .ok_or(Error {
Subtract { left, right } => { kind: ErrorKind::ArithmeticError,
Int(i32::try_from(self.eval_expr(left)?)? - i32::try_from(self.eval_expr(right)?)?) position: 0..0,
} })?),
Multiply { left, right } => { Subtract { left, right } => Int(i32::try_from(self.eval_expr(left)?)?
Int(i32::try_from(self.eval_expr(left)?)? * i32::try_from(self.eval_expr(right)?)?) .checked_sub(i32::try_from(self.eval_expr(right)?)?)
} .ok_or(Error {
Divide { left, right } => { kind: ErrorKind::ArithmeticError,
Int(i32::try_from(self.eval_expr(left)?)? / i32::try_from(self.eval_expr(right)?)?) position: 0..0,
} })?),
Multiply { left, right } => Int(i32::try_from(self.eval_expr(left)?)?
.checked_mul(i32::try_from(self.eval_expr(right)?)?)
.ok_or(Error {
kind: ErrorKind::ArithmeticError,
position: 0..0,
})?),
Divide { left, right } => Int(i32::try_from(self.eval_expr(left)?)?
.checked_div(i32::try_from(self.eval_expr(right)?)?)
.ok_or(Error {
kind: ErrorKind::ArithmeticError,
position: 0..0,
})?),
Lt { left, right } => { Lt { left, right } => {
Bool(i32::try_from(self.eval_expr(left)?)? < i32::try_from(self.eval_expr(right)?)?) Bool(i32::try_from(self.eval_expr(left)?)? < i32::try_from(self.eval_expr(right)?)?)
} }