Merge pull request #28 from AlexBethel/bf-functio
This commit is contained in:
Able
GitHub
commit
723719b9df
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@ -1,5 +1,7 @@
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use std::ops::Range;
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use crate::brian::InterpretError;
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#[derive(Debug, Clone)]
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pub struct Error {
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pub kind: ErrorKind,
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@ -15,4 +17,6 @@ pub enum ErrorKind {
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MeloVariable(String),
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TypeError(String),
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TopLevelBreak,
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ArithmeticError,
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BfInterpretError(InterpretError),
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}
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301
src/interpret.rs
301
src/interpret.rs
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@ -8,13 +8,16 @@
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#[deny(missing_docs)]
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use std::collections::HashMap;
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use std::convert::TryFrom;
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use std::{
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convert::TryFrom,
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io::{stdout, Write},
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};
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use crate::{
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base_55,
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error::{Error, ErrorKind},
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parser::item::{Expr, Iden, Item, Stmt},
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variables::{Value, Variable},
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variables::{Functio, Value, Variable},
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};
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/// An environment for executing AbleScript code.
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@ -110,34 +113,86 @@ impl ExecEnv {
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use Expr::*;
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use Value::*;
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// NOTE(Alex): This is quite nasty, and should probably be
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// re-done using macros or something.
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// NOTE(Alex): This block will get a whole lot cleaner once
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// Ondra's parser stuff gets merged (specifically 97fb19e).
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// For now, though, we've got a bunch of manually-checked
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// unreachable!()s in here which makes me sad...
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Ok(match expr {
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Add { left, right } => {
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Int(i32::try_from(self.eval_expr(left)?)? + i32::try_from(self.eval_expr(right)?)?)
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}
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Subtract { left, right } => {
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Int(i32::try_from(self.eval_expr(left)?)? - i32::try_from(self.eval_expr(right)?)?)
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}
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Multiply { left, right } => {
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Int(i32::try_from(self.eval_expr(left)?)? * i32::try_from(self.eval_expr(right)?)?)
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}
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Divide { left, right } => {
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Int(i32::try_from(self.eval_expr(left)?)? / i32::try_from(self.eval_expr(right)?)?)
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}
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Lt { left, right } => {
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Bool(i32::try_from(self.eval_expr(left)?)? < i32::try_from(self.eval_expr(right)?)?)
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}
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Gt { left, right } => {
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Bool(i32::try_from(self.eval_expr(left)?)? > i32::try_from(self.eval_expr(right)?)?)
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}
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Eq { left, right } => Bool(self.eval_expr(left)? == self.eval_expr(right)?),
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Neq { left, right } => Bool(self.eval_expr(left)? != self.eval_expr(right)?),
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And { left, right } => {
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Bool(bool::from(self.eval_expr(left)?) && bool::from(self.eval_expr(right)?))
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}
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Or { left, right } => {
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Bool(bool::from(self.eval_expr(left)?) || bool::from(self.eval_expr(right)?))
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// Binary expressions.
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Add { left, right }
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| Subtract { left, right }
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| Multiply { left, right }
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| Divide { left, right }
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| Lt { left, right }
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| Gt { left, right }
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| Eq { left, right }
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| Neq { left, right }
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| And { left, right }
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| Or { left, right } => {
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let left = self.eval_expr(left)?;
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let right = self.eval_expr(right)?;
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match expr {
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// Arithmetic operators.
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Add { .. }
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| Subtract { .. }
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| Multiply { .. }
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| Divide { .. } => {
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let left = i32::try_from(left)?;
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let right = i32::try_from(right)?;
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let res = match expr {
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Add { .. } => left.checked_add(right),
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Subtract { .. } => left.checked_sub(right),
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Multiply { .. } => left.checked_mul(right),
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Divide { .. } => left.checked_div(right),
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_ => unreachable!(),
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}
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.ok_or(Error {
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kind: ErrorKind::ArithmeticError,
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position: 0..0,
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})?;
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Int(res)
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}
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// Numeric comparisons.
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Lt { .. } | Gt { .. } => {
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let left = i32::try_from(left)?;
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let right = i32::try_from(right)?;
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let res = match expr {
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Lt { .. } => left < right,
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Gt { .. } => left > right,
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_ => unreachable!(),
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};
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Bool(res)
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}
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// General comparisons.
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Eq { .. } | Neq { .. } => {
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let res = match expr {
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Eq { .. } => left == right,
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Neq { .. } => left != right,
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_ => unreachable!(),
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};
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Bool(res)
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}
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// Logical connectives.
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And { .. } | Or { .. } => {
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let left = bool::from(left);
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let right = bool::from(right);
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let res = match expr {
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And { .. } => left && right,
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Or { .. } => left || right,
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_ => unreachable!(),
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};
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Bool(res)
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}
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// That's all the binary operations.
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_ => unreachable!(),
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}
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}
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Not(expr) => Bool(!bool::from(self.eval_expr(expr)?)),
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Literal(value) => value.clone(),
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@ -157,29 +212,63 @@ impl ExecEnv {
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None => Value::Nul,
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};
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// There's always at least one stack frame on the
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// stack if we're evaluating something, so we can
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// `unwrap` here.
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self.stack.iter_mut().last().unwrap().variables.insert(
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iden.0.clone(),
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Variable {
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melo: false,
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value: init,
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},
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);
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self.decl_var(&iden.0, init);
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}
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Stmt::FunctionDeclaration {
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iden: _,
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args: _,
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body: _,
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} => todo!(),
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Stmt::BfFDeclaration { iden: _, body: _ } => todo!(),
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Stmt::BfFDeclaration { iden, body } => {
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self.decl_var(
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&iden.0,
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Value::Functio(Functio::BfFunctio(body.as_bytes().into())),
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);
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}
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Stmt::If { cond, body } => {
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if self.eval_expr(cond)?.into() {
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return self.eval_items_hs(body);
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}
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}
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Stmt::FunctionCall { iden: _, args: _ } => todo!(),
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Stmt::FunctionCall { iden, args } => {
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let func = self.get_var(&iden.0)?;
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match func {
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Value::Functio(func) => {
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match func {
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Functio::BfFunctio(body) => {
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let mut input: Vec<u8> = vec![];
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for arg in args {
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self.eval_expr(arg)?.bf_write(&mut input);
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}
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println!("input = {:?}", input);
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let mut output = vec![];
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crate::brian::interpret_with_io(&body, &input as &[_], &mut output)
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.map_err(|e| Error {
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kind: ErrorKind::BfInterpretError(e),
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position: 0..0,
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})?;
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// I guess Brainfuck functions write
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// output to stdout? It's not quite
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// clear to me what else to do. ~~Alex
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stdout()
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.write_all(&output)
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.expect("Failed to write to stdout");
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}
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Functio::AbleFunctio(_) => {
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todo!()
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}
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}
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}
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_ => {
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return Err(Error {
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kind: ErrorKind::TypeError(iden.0.to_owned()),
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position: 0..0,
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})
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}
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}
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}
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Stmt::Loop { body } => loop {
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let res = self.eval_items_hs(body)?;
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match res {
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@ -268,4 +357,134 @@ impl ExecEnv {
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}),
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}
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}
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/// Declares a new variable, with the given initial value.
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fn decl_var(&mut self, name: &str, value: Value) {
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self.stack
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.iter_mut()
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.last()
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.expect("Declaring variable on empty stack")
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.variables
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.insert(name.to_owned(), Variable { melo: false, value });
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn basic_expression_test() {
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// Check that 2 + 2 = 4.
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let mut env = ExecEnv::new();
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assert_eq!(
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env.eval_items(&[Item::Expr(Expr::Add {
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left: Box::new(Expr::Literal(Value::Int(2))),
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right: Box::new(Expr::Literal(Value::Int(2))),
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})])
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.unwrap(),
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Value::Int(4)
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)
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}
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#[test]
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fn type_errors() {
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// The sum of an integer and a boolean results in a type
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// error.
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let mut env = ExecEnv::new();
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assert!(matches!(
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env.eval_items(&[Item::Expr(Expr::Add {
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left: Box::new(Expr::Literal(Value::Int(i32::MAX))),
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right: Box::new(Expr::Literal(Value::Bool(false))),
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})]),
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Err(Error {
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kind: ErrorKind::TypeError(_),
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position: _,
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})
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));
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}
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#[test]
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fn overflow_should_not_panic() {
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// Integer overflow should throw a recoverable error instead
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// of panicking.
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let mut env = ExecEnv::new();
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assert!(matches!(
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env.eval_items(&[Item::Expr(Expr::Add {
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left: Box::new(Expr::Literal(Value::Int(i32::MAX))),
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right: Box::new(Expr::Literal(Value::Int(1))),
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})]),
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Err(Error {
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kind: ErrorKind::ArithmeticError,
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position: _,
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})
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));
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// And the same for divide by zero.
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assert!(matches!(
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env.eval_items(&[Item::Expr(Expr::Divide {
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left: Box::new(Expr::Literal(Value::Int(1))),
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right: Box::new(Expr::Literal(Value::Int(0))),
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})]),
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Err(Error {
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kind: ErrorKind::ArithmeticError,
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position: _,
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})
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));
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}
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// From here on out, I'll use this function to parse and run
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// expressions, because writing out abstract syntax trees by hand
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// takes forever and is error-prone.
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fn eval(env: &mut ExecEnv, src: &str) -> Result<Value, Error> {
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let mut parser = crate::parser::Parser::new(src);
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// We can assume there won't be any syntax errors in the
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// interpreter tests.
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let ast = parser.init().unwrap();
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env.eval_items(&ast)
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}
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#[test]
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fn variable_decl_and_assignment() {
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// Declaring and reading from a variable.
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assert_eq!(
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eval(&mut ExecEnv::new(), "var foo = 32; foo + 1").unwrap(),
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Value::Int(33)
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);
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// It should be possible to overwrite variables as well.
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assert_eq!(
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eval(&mut ExecEnv::new(), "var bar = 10; bar = 20; bar").unwrap(),
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Value::Int(20)
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);
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// But variable assignment should be illegal when the variable
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// hasn't been declared in advance.
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eval(&mut ExecEnv::new(), "baz = 10;").unwrap_err();
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}
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#[test]
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fn variable_persistence() {
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// Global variables should persist between invocations of
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// ExecEnv::eval_items().
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let mut env = ExecEnv::new();
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eval(&mut env, "var foo = 32;").unwrap();
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assert_eq!(eval(&mut env, "foo").unwrap(), Value::Int(32));
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}
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#[test]
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fn scope_visibility_rules() {
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// Declaration and assignment of variables declared in an `if`
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// statement should have no effect on those declared outside
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// of it.
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assert_eq!(
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eval(
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&mut ExecEnv::new(),
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"var foo = 1; if (true) { var foo = 2; foo = 3; } foo"
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)
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.unwrap(),
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Value::Int(1)
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);
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}
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}
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|
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@ -1,8 +1,11 @@
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use std::{convert::TryFrom, fmt::Display};
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use std::{convert::TryFrom, fmt::Display, io::Write};
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|
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use rand::Rng;
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|
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use crate::error::{Error, ErrorKind};
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use crate::{
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error::{Error, ErrorKind},
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parser::item::Item,
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};
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#[derive(Debug, Clone, PartialEq)]
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pub enum Abool {
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@ -31,23 +34,102 @@ impl From<Abool> for bool {
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}
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}
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#[derive(Debug, Clone, PartialEq)]
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pub enum Functio {
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BfFunctio(Vec<u8>),
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AbleFunctio(Vec<Item>),
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}
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#[derive(Debug, Clone, PartialEq)]
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pub enum Value {
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Nul,
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Str(String),
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Int(i32),
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Bool(bool),
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Abool(Abool),
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Nul,
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Functio(Functio),
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}
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impl Value {
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/// Writes an AbleScript value to a Brainfuck input stream. This
|
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/// should generally only be called on `Write`rs that cannot fail,
|
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/// e.g., `Vec<u8>`, because any IO errors will cause a panic.
|
||||
///
|
||||
/// The mapping from values to encodings is as follows, where all
|
||||
/// multi-byte integers are little-endian:
|
||||
///
|
||||
/// | AbleScript representation | Brainfuck representation |
|
||||
/// |---------------------------|-------------------------------------------------------------|
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/// | Nul | `00` |
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/// | Str | `01` [length, 4 bytes] [string, \[LENGTH\] bytes, as UTF-8] |
|
||||
/// | Int | `02` [value, 4 bytes] |
|
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/// | Bool | `03` `00` false, `03` `01` true. |
|
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/// | Abool | `04` `00` never, `04` `01` always, `04` `02` sometimes. |
|
||||
/// | Brainfuck Functio | `05` `00` [length, 4 bytes] [source code, \[LENGTH\] bytes] |
|
||||
/// | AbleScript Functio | `05` `01` (todo, not yet finalized or implemented) |
|
||||
///
|
||||
/// The existing mappings should never change, as they are
|
||||
/// directly visible from Brainfuck code and modifying them would
|
||||
/// break a significant amount of AbleScript code. If more types
|
||||
/// are added in the future, they should be assigned the remaining
|
||||
/// discriminant bytes from 06..FF.
|
||||
pub fn bf_write(&mut self, stream: &mut impl Write) {
|
||||
match self {
|
||||
Value::Nul => stream.write_all(&[0]),
|
||||
Value::Str(s) => stream
|
||||
.write_all(&[1])
|
||||
.and_then(|_| stream.write_all(&(s.len() as u32).to_le_bytes()))
|
||||
.and_then(|_| stream.write_all(&s.as_bytes())),
|
||||
Value::Int(v) => stream
|
||||
.write_all(&[2])
|
||||
.and_then(|_| stream.write_all(&v.to_le_bytes())),
|
||||
Value::Bool(b) => stream
|
||||
.write_all(&[3])
|
||||
.and_then(|_| stream.write_all(&[*b as _])),
|
||||
Value::Abool(a) => stream.write_all(&[4]).and_then(|_| {
|
||||
stream.write_all(&[match *a {
|
||||
Abool::Never => 0,
|
||||
Abool::Sometimes => 2,
|
||||
Abool::Always => 1,
|
||||
}])
|
||||
}),
|
||||
Value::Functio(f) => stream.write_all(&[5]).and_then(|_| match f {
|
||||
Functio::BfFunctio(f) => stream
|
||||
.write_all(&[0])
|
||||
.and_then(|_| stream.write_all(&(f.len() as u32).to_le_bytes()))
|
||||
.and_then(|_| stream.write_all(&f)),
|
||||
Functio::AbleFunctio(_) => {
|
||||
todo!()
|
||||
}
|
||||
}),
|
||||
}
|
||||
.expect("Failed to write to Brainfuck input");
|
||||
}
|
||||
}
|
||||
|
||||
impl Display for Value {
|
||||
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
||||
match self {
|
||||
Value::Nul => write!(f, "nul"),
|
||||
Value::Str(v) => write!(f, "{}", v),
|
||||
Value::Int(v) => write!(f, "{}", v),
|
||||
Value::Bool(v) => write!(f, "{}", v),
|
||||
Value::Abool(v) => write!(f, "{}", v),
|
||||
Value::Nul => write!(f, "nul"),
|
||||
Value::Functio(v) => match v {
|
||||
Functio::BfFunctio(source) => {
|
||||
write!(
|
||||
f,
|
||||
"{}",
|
||||
String::from_utf8(source.to_owned())
|
||||
.expect("Brainfuck functio source should be UTF-8")
|
||||
)
|
||||
}
|
||||
Functio::AbleFunctio(source) => {
|
||||
// TODO: what's the proper way to display an
|
||||
// AbleScript functio?
|
||||
write!(f, "{:?}", source)
|
||||
}
|
||||
},
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -84,6 +166,8 @@ impl From<Value> for bool {
|
|||
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.
|
||||
|
|
|
|||
Loading…
Reference in a new issue