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Fix all 0..0 span placeholders in interpret.rs

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This commit is contained in:
Alex Bethel 2021-06-07 19:57:44 -05:00
parent d8f462e0b5
commit ce20611c07
2 changed files with 101 additions and 106 deletions
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129
src/interpret.rs
View file

@ -7,17 +7,18 @@
//! evaluate or execute any number of expressions or statements.
#[deny(missing_docs)]
use std::collections::HashMap;
use std::{
convert::TryFrom,
collections::HashMap,
io::{stdout, Write},
ops::Range,
process::exit,
usize,
};
use rand::random;
use crate::{
ast::{Expr, Stmt, StmtKind},
ast::{Expr, Iden, Stmt, StmtKind},
base_55,
error::{Error, ErrorKind},
variables::{Functio, Value, Variable},
@ -43,16 +44,16 @@ struct Scope {
/// The reason a successful series of statements halted.
enum HaltStatus {
/// The last statement in the list evaluated to this value.
Value(Value),
/// We ran out of statements to execute.
Finished,
/// A `break` statement occurred and was not caught by a `loop`
/// statement.
Break,
/// A `break` statement occurred at the given span, and was not
/// caught by a `loop` statement up to this point.
Break(Range<usize>),
/// A `hopback` statement occurred and was not caught by a `loop`
/// statement.
Hopback,
/// A `hopback` statement occurred at the given span, and was not
/// caught by a `loop` statement up to this point.
Hopback(Range<usize>),
}
impl ExecEnv {
@ -67,14 +68,14 @@ impl ExecEnv {
/// Execute a set of Statements in their own stack frame. Return
/// an error if one or more of the Stmts failed to evaluate, or if
/// a `break` or `hopback` statement occurred at the top level.
pub fn eval_stmts(&mut self, stmts: &[Stmt]) -> Result<Value, Error> {
pub fn eval_stmts(&mut self, stmts: &[Stmt]) -> Result<(), Error> {
match self.eval_stmts_hs(stmts)? {
HaltStatus::Value(v) => Ok(v),
HaltStatus::Break | HaltStatus::Hopback => Err(Error {
HaltStatus::Finished => Ok(()),
HaltStatus::Break(span) | HaltStatus::Hopback(span) => Err(Error {
// It's an error to issue a `break` outside of a
// `loop` statement.
kind: ErrorKind::TopLevelBreak,
span: 0..0,
span: span,
}),
}
}
@ -88,10 +89,10 @@ impl ExecEnv {
let init_depth = self.stack.len();
self.stack.push(Default::default());
let mut final_result = Ok(HaltStatus::Value(Value::Nul));
let mut final_result = Ok(HaltStatus::Finished);
for stmt in stmts {
final_result = self.eval_stmt(stmt);
if !matches!(final_result, Ok(HaltStatus::Value(_))) {
if !matches!(final_result, Ok(HaltStatus::Finished)) {
break;
}
}
@ -115,8 +116,8 @@ impl ExecEnv {
match kind {
// Arithmetic operators.
Add | Subtract | Multiply | Divide => {
let lhs = i32::try_from(lhs)?;
let rhs = i32::try_from(rhs)?;
let lhs = lhs.to_i32(&expr.span)?;
let rhs = rhs.to_i32(&expr.span)?;
let res = match kind {
Add => lhs.checked_add(rhs),
@ -134,8 +135,8 @@ impl ExecEnv {
// Numeric comparisons.
Less | Greater => {
let lhs = i32::try_from(lhs)?;
let rhs = i32::try_from(rhs)?;
let lhs = lhs.to_i32(&expr.span)?;
let rhs = rhs.to_i32(&expr.span)?;
let res = match kind {
Less => lhs < rhs,
@ -157,8 +158,8 @@ impl ExecEnv {
// Logical connectives.
And | Or => {
let lhs = bool::from(lhs);
let rhs = bool::from(rhs);
let lhs = lhs.to_bool();
let rhs = rhs.to_bool();
let res = match kind {
And => lhs && rhs,
Or => lhs || rhs,
@ -168,9 +169,15 @@ impl ExecEnv {
}
}
}
Not(expr) => Bool(!bool::from(self.eval_expr(&expr)?)),
Not(expr) => Bool(!self.eval_expr(&expr)?.to_bool()),
Literal(value) => value.clone(),
Variable(name) => self.get_var(&name)?,
// TODO: not too happy with constructing an artificial
// Iden here.
Variable(name) => self.get_var(&Iden {
iden: name.to_owned(),
span: expr.span.clone(),
})?,
})
}
@ -203,12 +210,12 @@ impl ExecEnv {
// );
// }
StmtKind::If { cond, body } => {
if self.eval_expr(cond)?.into() {
if self.eval_expr(cond)?.to_bool() {
return self.eval_stmts_hs(&body.block);
}
}
StmtKind::Call { iden, args } => {
let func = self.get_var(&iden.iden)?;
let func = self.get_var(&iden)?;
match func {
Value::Functio(func) => {
match func {
@ -249,9 +256,9 @@ impl ExecEnv {
StmtKind::Loop { body } => loop {
let res = self.eval_stmts_hs(&body.block)?;
match res {
HaltStatus::Value(_) => {}
HaltStatus::Break => break,
HaltStatus::Hopback => continue,
HaltStatus::Finished => {}
HaltStatus::Break(_) => break,
HaltStatus::Hopback(_) => continue,
}
},
// This is missing as well. ~~Alex
@ -259,13 +266,13 @@ impl ExecEnv {
// self.get_var_mut(&iden.0)?.value = self.eval_expr(value)?;
// }
StmtKind::Break => {
return Ok(HaltStatus::Break);
return Ok(HaltStatus::Break(stmt.span.clone()));
}
StmtKind::HopBack => {
return Ok(HaltStatus::Hopback);
return Ok(HaltStatus::Hopback(stmt.span.clone()));
}
StmtKind::Melo(iden) => {
self.get_var_mut(&iden.iden)?.melo = true;
self.get_var_mut(&iden)?.melo = true;
}
StmtKind::Rlyeh => {
// Maybe print a creepy error message or something
@ -274,14 +281,14 @@ impl ExecEnv {
}
}
Ok(HaltStatus::Value(Value::Nul))
Ok(HaltStatus::Finished)
}
/// Get the value of a variable. Throw an error if the variable is
/// inaccessible or banned.
fn get_var(&self, name: &str) -> Result<Value, Error> {
fn get_var(&self, name: &Iden) -> Result<Value, Error> {
// One-letter names are reserved as base55 numbers.
let mut chars = name.chars();
let mut chars = name.iden.chars();
if let (Some(first), None) = (chars.next(), chars.next()) {
return Ok(Value::Int(base_55::char2num(first)));
}
@ -292,51 +299,49 @@ impl ExecEnv {
.stack
.iter()
.rev()
.find_map(|scope| scope.variables.get(name))
.find_map(|scope| scope.variables.get(&name.iden))
{
Some(var) => {
if !var.melo {
Ok(var.value.clone())
} else {
Err(Error {
kind: ErrorKind::MeloVariable(name.to_owned()),
// TODO: figure out some way to avoid this
// 0..0 dumbness
span: 0..0,
kind: ErrorKind::MeloVariable(name.iden.to_owned()),
span: name.span.clone(),
})
}
}
None => Err(Error {
kind: ErrorKind::UnknownVariable(name.to_owned()),
span: 0..0,
kind: ErrorKind::UnknownVariable(name.iden.to_owned()),
span: name.span.clone(),
}),
}
}
/// Get a mutable reference to a variable. Throw an error if the
/// variable is inaccessible or banned.
fn get_var_mut(&mut self, name: &str) -> Result<&mut Variable, Error> {
fn get_var_mut(&mut self, name: &Iden) -> Result<&mut Variable, Error> {
// This function has a lot of duplicated code with `get_var`,
// which I feel like is a bad sign...
match self
.stack
.iter_mut()
.rev()
.find_map(|scope| scope.variables.get_mut(name))
.find_map(|scope| scope.variables.get_mut(&name.iden))
{
Some(var) => {
if !var.melo {
Ok(var)
} else {
Err(Error {
kind: ErrorKind::MeloVariable(name.to_owned()),
span: 0..0,
kind: ErrorKind::MeloVariable(name.iden.to_owned()),
span: name.span.clone(),
})
}
}
None => Err(Error {
kind: ErrorKind::UnknownVariable(name.to_owned()),
span: 0..0,
kind: ErrorKind::UnknownVariable(name.iden.to_owned()),
span: name.span.clone(),
}),
}
}
@ -367,15 +372,15 @@ mod tests {
kind: ExprKind::BinOp {
lhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(2)),
span: 0..0,
span: 1..1,
}),
rhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(2)),
span: 0..0,
span: 1..1,
}),
kind: crate::ast::BinOpKind::Add,
},
span: 0..0
span: 1..1
})
.unwrap(),
Value::Int(4)
@ -392,15 +397,15 @@ mod tests {
kind: ExprKind::BinOp {
lhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(2)),
span: 0..0,
span: 1..1,
}),
rhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Bool(true)),
span: 0..0,
span: 1..1,
}),
kind: crate::ast::BinOpKind::Add,
},
span: 0..0
span: 1..1
}),
Err(Error {
kind: ErrorKind::TypeError(_),
@ -419,15 +424,15 @@ mod tests {
kind: ExprKind::BinOp {
lhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(i32::MAX)),
span: 0..0,
span: 1..1,
}),
rhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(1)),
span: 0..0,
span: 1..1,
}),
kind: crate::ast::BinOpKind::Add,
},
span: 0..0
span: 1..1
}),
Err(Error {
kind: ErrorKind::ArithmeticError,
@ -441,15 +446,15 @@ mod tests {
kind: ExprKind::BinOp {
lhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(1)),
span: 0..0,
span: 1..1,
}),
rhs: Box::new(Expr {
kind: ExprKind::Literal(Value::Int(0)),
span: 0..0,
span: 1..1,
}),
kind: crate::ast::BinOpKind::Divide,
},
span: 0..0
span: 1..1
}),
Err(Error {
kind: ErrorKind::ArithmeticError,
@ -467,7 +472,7 @@ mod tests {
// We can assume there won't be any syntax errors in the
// interpreter tests.
let ast = parser.init().unwrap();
env.eval_stmts(&ast)
env.eval_stmts(&ast).map(|()| Value::Nul)
}
#[test]

78
src/variables.rs
View file

@ -1,4 +1,4 @@
use std::{convert::TryFrom, fmt::Display, io::Write};
use std::{fmt::Display, io::Write, ops::Range};
use rand::Rng;
@ -51,7 +51,7 @@ pub enum Value {
}
impl Value {
/// Writes an AbleScript value to a Brainfuck input stream. This
/// Write an AbleScript value to a Brainfuck input stream. This
/// should generally only be called on `Write`rs that cannot fail,
/// e.g., `Vec<u8>`, because any IO errors will cause a panic.
///
@ -105,6 +105,38 @@ impl Value {
}
.expect("Failed to write to Brainfuck input");
}
/// Attempt to coerce a Value to an integer. If the conversion
/// fails, the generated error message is associated with the
/// given span.
pub fn to_i32(self, span: &Range<usize>) -> Result<i32, Error> {
match self {
Value::Int(i) => Ok(i),
_ => Err(Error {
kind: ErrorKind::TypeError(format!("Expected int, got {}", self)),
span: span.clone(),
}),
}
}
/// Coerce a Value to a boolean. The conversion cannot fail.
pub fn to_bool(self) -> bool {
match self {
// Booleans and abooleans have a trivial conversion.
Value::Bool(b) => b,
Value::Abool(b) => b.into(),
// The empty string is falsey, other strings are truthy.
Value::Str(s) => s.len() != 0,
// 0 is falsey, nonzero is truthy.
Value::Int(x) => x != 0,
// Functios are always truthy.
Value::Functio(_) => true,
// And nul is truthy as a symbol of the fact that the
// deep, fundamental truth of this world is nothing but
// the eternal void.
Value::Nul => true,
}
}
}
impl Display for Value {
@ -134,48 +166,6 @@ impl Display for Value {
}
}
impl TryFrom<Value> for i32 {
type Error = Error;
fn try_from(value: Value) -> Result<Self, Self::Error> {
match value {
Value::Int(i) => Ok(i),
_ => Err(Error {
kind: ErrorKind::TypeError(format!("Expected int, got {}", value)),
// TODO: either add some kind of metadata to `Value`
// so we can tell where the value came from and assign
// this `position` correctly, or re-write the
// `error::Error` struct so we can omit the `position`
// when using some error kinds.
span: 0..0,
}),
}
}
}
// Coercions from a value to a boolean always succeed, so every value
// can be used in an `if` statement. C does things that way, so how
// could it possibly be a bad idea?
impl From<Value> for bool {
fn from(value: Value) -> Self {
match value {
// Booleans and abooleans have a trivial conversion.
Value::Bool(b) => b,
Value::Abool(b) => b.into(),
// The empty string is falsey, other strings are truthy.
Value::Str(s) => s.len() != 0,
// 0 is falsey, nonzero is truthy.
Value::Int(x) => x != 0,
// Functios are always truthy.
Value::Functio(_) => true,
// And nul is truthy as a symbol of the fact that the
// deep, fundamental truth of this world is nothing but
// the eternal void.
Value::Nul => true,
}
}
}
#[derive(Debug)]
pub struct Variable {
pub melo: bool,