forked from AbleScript/ablescript
Implement read
semantics in interpreter
Also added a test file `iotest.able` to just read data and print it (the `cat` of AbleScript I guess).
This commit is contained in:
parent
2ec416db97
commit
f7ac2a1a43
5
able-script-test/iotest.able
Normal file
5
able-script-test/iotest.able
Normal file
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@ -0,0 +1,5 @@
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var data;
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loop {
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data read;
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data print;
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}
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16
src/error.rs
16
src/error.rs
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@ -1,14 +1,14 @@
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use std::ops::Range;
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use std::{io, ops::Range};
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use crate::{brian::InterpretError, lexer::Token};
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#[derive(Debug, Clone)]
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#[derive(Debug)]
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pub struct Error {
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pub kind: ErrorKind,
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pub span: Range<usize>,
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}
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#[derive(Debug, Clone)]
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#[derive(Debug)]
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pub enum ErrorKind {
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SyntaxError(String),
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UnexpectedEof,
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@ -22,6 +22,7 @@ pub enum ErrorKind {
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BfInterpretError(InterpretError),
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MismatchedArgumentError,
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MissingLhs,
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IOError(io::Error),
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}
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impl Error {
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@ -35,3 +36,12 @@ impl Error {
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Self::new(ErrorKind::UnexpectedEof, index..index)
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}
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}
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impl From<io::Error> for Error {
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fn from(e: io::Error) -> Self {
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Self {
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kind: ErrorKind::IOError(e),
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span: 0..0,
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}
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}
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}
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@ -9,12 +9,11 @@
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#![deny(missing_docs)]
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use std::{
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cell::RefCell,
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collections::HashMap,
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io::{stdout, Write},
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collections::{HashMap, VecDeque},
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io::{stdin, stdout, Read, Write},
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ops::Range,
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process::exit,
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rc::Rc,
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usize,
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};
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use rand::random;
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@ -32,6 +31,13 @@ pub struct ExecEnv {
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/// top-most (newest) stack frame, and `stack[0]` is the
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/// bottom-most (oldest) stack frame.
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stack: Vec<Scope>,
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/// The `read` statement maintains a buffer of up to 7 bits,
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/// because input comes from the operating system 8 bits at a time
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/// (via stdin) but gets delivered to AbleScript 3 bits at a time
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/// (via the `read` statement). We store each of those bits as
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/// booleans to facilitate easy manipulation.
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read_buf: VecDeque<bool>,
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}
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/// A set of visible variable and function definitions in a single
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@ -58,6 +64,10 @@ enum HaltStatus {
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Hopback(Range<usize>),
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}
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/// The number of bits the `read` statement reads at once from
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/// standard input.
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pub const READ_BITS: u8 = 3;
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impl ExecEnv {
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/// Create a new Scope with no predefined variable definitions or
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/// other information.
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@ -65,6 +75,7 @@ impl ExecEnv {
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Self {
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// We always need at least one stackframe.
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stack: vec![Default::default()],
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read_buf: Default::default(),
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}
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}
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@ -205,13 +216,15 @@ impl ExecEnv {
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self.decl_var(&iden.iden, init);
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}
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StmtKind::Functio { iden, params, body } => self.decl_var(
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&iden.iden,
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Value::Functio(Functio::AbleFunctio {
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params: params.iter().map(|iden| iden.iden.to_string()).collect(),
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body: body.block.to_owned(),
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}),
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),
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StmtKind::Functio { iden, params, body } => {
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self.decl_var(
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&iden.iden,
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Value::Functio(Functio::AbleFunctio {
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params: params.iter().map(|iden| iden.iden.to_string()).collect(),
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body: body.block.to_owned(),
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}),
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);
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}
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StmtKind::BfFunctio {
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iden,
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tape_len,
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@ -280,7 +293,15 @@ impl ExecEnv {
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.write_all(include_str!("rickroll").as_bytes())
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.expect("Failed to write to stdout");
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}
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StmtKind::Read(_) => todo!(),
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StmtKind::Read(iden) => {
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let mut value = 0;
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for _ in 0..READ_BITS {
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value <<= 1;
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value += self.get_bit()? as i32;
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}
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self.get_var_mut(&iden)?.value.replace(Value::Int(value));
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}
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}
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Ok(HaltStatus::Finished)
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@ -356,6 +377,26 @@ impl ExecEnv {
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Ok(())
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}
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/// Get a single bit from the bit buffer, or refill it from
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/// standard input if it is empty.
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fn get_bit(&mut self) -> Result<bool, Error> {
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const BITS_PER_BYTE: u8 = 8;
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if self.read_buf.is_empty() {
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let mut data = [0];
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stdin().read_exact(&mut data)?;
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for n in (0..BITS_PER_BYTE).rev() {
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self.read_buf.push_back(((data[0] >> n) & 1) != 0);
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}
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}
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Ok(self
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.read_buf
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.pop_front()
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.expect("We just pushed to the buffer if it was empty"))
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}
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/// Get the value of a variable. Throw an error if the variable is
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/// inaccessible or banned.
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fn get_var(&self, name: &Iden) -> Result<Value, Error> {
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