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Diffstat (limited to 'tests/examplefiles/eval.rs')
| -rw-r--r-- | tests/examplefiles/eval.rs | 606 |
1 files changed, 606 insertions, 0 deletions
diff --git a/tests/examplefiles/eval.rs b/tests/examplefiles/eval.rs new file mode 100644 index 00000000..17e585a0 --- /dev/null +++ b/tests/examplefiles/eval.rs @@ -0,0 +1,606 @@ +// ------------------------------------------------------------------------------------------------- +// Rick, a Rust intercal compiler. Save your souls! +// +// Copyright (c) 2015 Georg Brandl +// +// This program is free software; you can redistribute it and/or modify it under the terms of the +// GNU General Public License as published by the Free Software Foundation; either version 2 of the +// License, or (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without +// even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with this program; +// if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +// ------------------------------------------------------------------------------------------------- + +/// Interprets INTERCAL source. +/// +/// The evaluator is used when rick is called with `-i`, or when the compiler generates +/// the output while compiling (in the constant-output case). + +use std::fmt::{ Debug, Display }; +use std::io::Write; +use std::u16; + +use err::{ Res, IE123, IE129, IE252, IE275, IE555, IE633, IE774, IE994 }; +use ast::{ self, Program, Stmt, StmtBody, ComeFrom, Expr, Var, VType }; +use stdops::{ Bind, Array, write_number, read_number, check_chance, check_ovf, pop_jumps, + get_random_seed, mingle, select, and_16, and_32, or_16, or_32, xor_16, xor_32 }; + + +/// Represents a value (either 16-bit or 32-bit) at runtime. +#[derive(Clone, PartialEq, Eq, Debug)] +pub enum Val { + I16(u16), + I32(u32), +} + +impl Val { + /// Cast as a 16-bit value; returns an error if 32-bit and too big. + pub fn as_u16(&self) -> Res<u16> { + match *self { + Val::I16(v) => Ok(v), + Val::I32(v) => { + if v > (u16::MAX as u32) { + return IE275.err(); + } + Ok(v as u16) + } + } + } + + /// Cast as a 32-bit value; always succeeds. + pub fn as_u32(&self) -> u32 { + match *self { + Val::I16(v) => v as u32, + Val::I32(v) => v + } + } + + /// Cast as an usize value; always succeeds. + pub fn as_usize(&self) -> usize { + self.as_u32() as usize + } + + /// Create from a 32-bit value; will select the smallest possible type. + pub fn from_u32(v: u32) -> Val { + if v & 0xFFFF == v { + Val::I16(v as u16) + } else { + Val::I32(v) + } + } +} + +/// The state of the interpreter's evaluator. +pub struct Eval<'a> { + /// Program to execute. + program: &'a Program, + /// Stream to use for printing output. + stdout: &'a mut Write, + /// Whether to print debugging output during execution. + debug: bool, + /// Variable bindings for the four types of variables. + spot: Vec<Bind<u16>>, + twospot: Vec<Bind<u32>>, + tail: Vec<Bind<Array<u16>>>, + hybrid: Vec<Bind<Array<u32>>>, + /// The infamous NEXT stack, capable of holding 80 elements. + jumps: Vec<ast::LogLine>, + /// Abstain counter for each statement. + abstain: Vec<u32>, + /// Binary I/O "tape" state. + last_in: u8, + last_out: u8, + /// Random number generator state. + rand_st: u32, + /// Counts the number of executed statements. + stmt_ctr: usize, +} + +/// Represents the control flow effect of an executed statement. +enum StmtRes { + /// normal execution, next statement + Next, + /// jump around, from DO ... NEXT + Jump(usize), + /// jump back, from RESUME + Back(usize), + /// start from the first statement, from TRY AGAIN + FromTop, + /// end the program, from GIVE UP + End, +} + +impl<'a> Eval<'a> { + /// Construct a new evaluator. + pub fn new(program: &'a Program, stdout: &'a mut Write, debug: bool, + random: bool) -> Eval<'a> { + let abs = program.stmts.iter().map(|stmt| stmt.props.disabled as u32).collect(); + let nvars = (program.var_info.0.len(), + program.var_info.1.len(), + program.var_info.2.len(), + program.var_info.3.len()); + Eval { + program: program, + stdout: stdout, + debug: debug, + spot: vec![Bind::new(0); nvars.0], + twospot: vec![Bind::new(0); nvars.1], + tail: vec![Bind::new(Array::empty()); nvars.2], + hybrid: vec![Bind::new(Array::empty()); nvars.3], + jumps: Vec::with_capacity(80), + rand_st: if random { get_random_seed() } else { 0 }, + abstain: abs, + last_in: 0, + last_out: 0, + stmt_ctr: 0, + } + } + + /// Interpret the program. Returns either the number of executed statements, + /// or an error (RtError). + pub fn eval(&mut self) -> Res<usize> { + let mut pctr = 0; // index of current statement + let program = self.program.clone(); + let nstmts = program.stmts.len(); + loop { + // check for falling off the end + if pctr >= nstmts { + // if the last statement was a TRY AGAIN, falling off the end is fine + if let StmtBody::TryAgain = program.stmts[program.stmts.len() - 1].body { + break; + } + return IE633.err(); + } + self.stmt_ctr += 1; + let stmt = &program.stmts[pctr]; + // execute statement if not abstained + if self.abstain[pctr] == 0 { + // check execution chance + let (passed, rand_st) = check_chance(stmt.props.chance, self.rand_st); + self.rand_st = rand_st; + if passed { + // try to eval this statement + let res = match self.eval_stmt(stmt) { + // on error, set the correct line number and bubble up + Err(mut err) => { + err.set_line(stmt.props.onthewayto); + // special treatment for NEXT + if let StmtBody::DoNext(n) = stmt.body { + if let Some(i) = program.labels.get(&n) { + err.set_line(program.stmts[*i as usize].props.srcline); + } + } + return Err(err); + } + Ok(res) => res + }; + // handle control flow effects + match res { + StmtRes::Next => { } + StmtRes::Jump(n) => { + self.jumps.push(pctr as u16); // push the line with the NEXT + pctr = n; + continue; // do not increment or check for COME FROMs + } + StmtRes::Back(n) => { + pctr = n; // will be incremented below after COME FROM check + } + StmtRes::FromTop => { + pctr = 0; // start from the beginning, do not push any stack + continue; + } + StmtRes::End => break, + } + } + } + // if we are on the line with the compiler bug, error out + if pctr == self.program.bugline as usize { + return IE774.err_with(None, stmt.props.onthewayto); + } + // try to determine if we have to go to a COME FROM statement + // (note: in general, program.stmts[pctr] != stmt) + // + // the static COME FROM is always a possibility + let mut maybe_next = program.stmts[pctr].comefrom; + // the complicated case: evaluate all computed-come-from expressions + let my_label = program.stmts[pctr].props.label; + if program.uses_complex_comefrom && my_label > 0 { + for (i, stmt) in program.stmts.iter().enumerate() { + if let StmtBody::ComeFrom(ComeFrom::Expr(ref e)) = stmt.body { + let v = try!(try!(self.eval_expr(e)).as_u16()); + if v == my_label { + // as soon as we have multiple candidates, we can bail out + if maybe_next.is_some() { + return IE555.err(); + } + maybe_next = Some(i as u16); + } + } + } + } + // check for COME FROMs from this line + if let Some(next) = maybe_next { + let next = next as usize; + // check for abstained COME FROM + if self.abstain[next] == 0 { + // the COME FROM can also have a % chance + let (passed, rand_st) = check_chance(program.stmts[next].props.chance, + self.rand_st); + self.rand_st = rand_st; + if passed { + pctr = next; + continue; + } + } + } + // no COME FROM, normal execution + pctr += 1; + } + Ok(self.stmt_ctr) + } + + /// Interpret a single statement. + fn eval_stmt(&mut self, stmt: &Stmt) -> Res<StmtRes> { + if self.debug { + println!("\nExecuting Stmt #{} (state before following)", self.stmt_ctr); + self.dump_state(); + println!("{}", stmt); + } + match stmt.body { + StmtBody::Calc(ref var, ref expr) => { + let val = try!(self.eval_expr(expr)); + try!(self.assign(var, val)); + Ok(StmtRes::Next) + } + StmtBody::Dim(ref var, ref exprs) => { + try!(self.array_dim(var, exprs)); + Ok(StmtRes::Next) + } + StmtBody::DoNext(n) => { + match self.program.labels.get(&n) { + // too many jumps on stack already? + Some(_) if self.jumps.len() >= 80 => IE123.err(), + Some(i) => Ok(StmtRes::Jump(*i as usize)), + None => IE129.err(), + } + } + StmtBody::ComeFrom(_) => { + // nothing to do here at runtime + Ok(StmtRes::Next) + } + StmtBody::Resume(ref expr) => { + let n = try!(self.eval_expr(expr)).as_u32(); + // this expect() is safe: if the third arg is true, there will + // be no Ok(None) returns + let next = try!(pop_jumps(&mut self.jumps, n, true, 0)) + .expect("https://xkcd.com/378/ ?!"); + Ok(StmtRes::Back(next as usize)) + } + StmtBody::Forget(ref expr) => { + let n = try!(self.eval_expr(expr)).as_u32(); + try!(pop_jumps(&mut self.jumps, n, false, 0)); + Ok(StmtRes::Next) + } + StmtBody::Ignore(ref vars) => { + for var in vars { + self.set_rw(var, false); + } + Ok(StmtRes::Next) + } + StmtBody::Remember(ref vars) => { + for var in vars { + self.set_rw(var, true); + } + Ok(StmtRes::Next) + } + StmtBody::Stash(ref vars) => { + for var in vars { + self.stash(var); + } + Ok(StmtRes::Next) + } + StmtBody::Retrieve(ref vars) => { + for var in vars { + try!(self.retrieve(var)); + } + Ok(StmtRes::Next) + } + StmtBody::Abstain(ref expr, ref whats) => { + let f: Box<Fn(u32) -> u32> = if let Some(ref e) = *expr { + let n = try!(self.eval_expr(e)).as_u32(); + box move |v: u32| v.saturating_add(n) + } else { + box |_| 1 + }; + for what in whats { + self.abstain(what, &*f); + } + Ok(StmtRes::Next) + } + StmtBody::Reinstate(ref whats) => { + for what in whats { + self.abstain(what, &|v: u32| v.saturating_sub(1)); + } + Ok(StmtRes::Next) + } + StmtBody::ReadOut(ref vars) => { + for var in vars { + match *var { + // read out whole array + Expr::Var(ref var) if var.is_dim() => { + try!(self.array_readout(var)); + } + // read out single var or array element + Expr::Var(ref var) => { + let varval = try!(self.lookup(var)); + try!(write_number(self.stdout, varval.as_u32(), 0)); + } + // read out constant + Expr::Num(_, v) => try!(write_number(self.stdout, v, 0)), + // others will not be generated + _ => return IE994.err(), + }; + } + Ok(StmtRes::Next) + } + StmtBody::WriteIn(ref vars) => { + for var in vars { + if var.is_dim() { + // write in whole array + try!(self.array_writein(var)); + } else { + // write in single var or array element + let n = try!(read_number(0)); + try!(self.assign(var, Val::from_u32(n))); + } + } + Ok(StmtRes::Next) + } + // this one is only generated by the constant-program optimizer + StmtBody::Print(ref s) => { + if let Err(_) = self.stdout.write(&s) { + return IE252.err(); + } + Ok(StmtRes::Next) + } + StmtBody::TryAgain => Ok(StmtRes::FromTop), + StmtBody::GiveUp => Ok(StmtRes::End), + StmtBody::Error(ref e) => Err((*e).clone()), + } + } + + /// Evaluate an expression to a value. + fn eval_expr(&self, expr: &Expr) -> Res<Val> { + match *expr { + Expr::Num(vtype, v) => match vtype { + VType::I16 => Ok(Val::I16(v as u16)), + VType::I32 => Ok(Val::I32(v)), + }, + Expr::Var(ref var) => self.lookup(var), + Expr::Mingle(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)).as_u32(); + let w = try!(self.eval_expr(wx)).as_u32(); + let v = try!(check_ovf(v, 0)); + let w = try!(check_ovf(w, 0)); + Ok(Val::I32(mingle(v, w))) + } + Expr::Select(vtype, ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + if vtype == VType::I16 { + Ok(Val::I16(select(v.as_u32(), try!(w.as_u16()) as u32) as u16)) + } else { + Ok(Val::I32(select(v.as_u32(), w.as_u32()))) + } + } + Expr::And(vtype, ref vx) => { + let v = try!(self.eval_expr(vx)); + match vtype { + VType::I16 => Ok(Val::I16(and_16(try!(v.as_u16()) as u32) as u16)), + VType::I32 => Ok(Val::I32(and_32(v.as_u32()))), + } + } + Expr::Or(vtype, ref vx) => { + let v = try!(self.eval_expr(vx)); + match vtype { + VType::I16 => Ok(Val::I16(or_16(try!(v.as_u16()) as u32) as u16)), + VType::I32 => Ok(Val::I32(or_32(v.as_u32()))), + } + } + Expr::Xor(vtype, ref vx) => { + let v = try!(self.eval_expr(vx)); + match vtype { + VType::I16 => Ok(Val::I16(xor_16(try!(v.as_u16()) as u32) as u16)), + VType::I32 => Ok(Val::I32(xor_32(v.as_u32()))), + } + } + Expr::RsNot(ref vx) => { + let v = try!(self.eval_expr(vx)); + Ok(Val::I32(!v.as_u32())) + } + Expr::RsAnd(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() & w.as_u32())) + } + Expr::RsOr(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() | w.as_u32())) + } + Expr::RsXor(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() ^ w.as_u32())) + } + Expr::RsRshift(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() >> w.as_u32())) + } + Expr::RsLshift(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() << w.as_u32())) + } + // Expr::RsEqual(ref vx, ref wx) => { + // let v = try!(self.eval_expr(vx)); + // let w = try!(self.eval_expr(wx)); + // Ok(Val::I32((v.as_u32() == w.as_u32()) as u32)) + // } + Expr::RsNotEqual(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32((v.as_u32() != w.as_u32()) as u32)) + } + Expr::RsPlus(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() + w.as_u32())) + } + Expr::RsMinus(ref vx, ref wx) => { + let v = try!(self.eval_expr(vx)); + let w = try!(self.eval_expr(wx)); + Ok(Val::I32(v.as_u32() - w.as_u32())) + } + } + } + + #[inline] + fn eval_subs(&self, subs: &Vec<Expr>) -> Res<Vec<usize>> { + subs.iter().map(|v| self.eval_expr(v).map(|w| w.as_usize())).collect() + } + + /// Dimension an array. + fn array_dim(&mut self, var: &Var, dims: &Vec<Expr>) -> Res<()> { + let dims = try!(self.eval_subs(dims)); + match *var { + Var::A16(n, _) => self.tail[n].dimension(dims, 0), + Var::A32(n, _) => self.hybrid[n].dimension(dims, 0), + _ => return IE994.err(), + } + } + + /// Assign to a variable. + fn assign(&mut self, var: &Var, val: Val) -> Res<()> { + match *var { + Var::I16(n) => Ok(self.spot[n].assign(try!(val.as_u16()))), + Var::I32(n) => Ok(self.twospot[n].assign(val.as_u32())), + Var::A16(n, ref subs) => { + let subs = try!(self.eval_subs(subs)); + self.tail[n].set_md(subs, try!(val.as_u16()), 0) + } + Var::A32(n, ref subs) => { + let subs = try!(self.eval_subs(subs)); + self.hybrid[n].set_md(subs, val.as_u32(), 0) + } + } + } + + /// Look up the value of a variable. + fn lookup(&self, var: &Var) -> Res<Val> { + match *var { + Var::I16(n) => Ok(Val::I16(self.spot[n].val)), + Var::I32(n) => Ok(Val::I32(self.twospot[n].val)), + Var::A16(n, ref subs) => { + let subs = try!(self.eval_subs(subs)); + self.tail[n].get_md(subs, 0).map(Val::I16) + } + Var::A32(n, ref subs) => { + let subs = try!(self.eval_subs(subs)); + self.hybrid[n].get_md(subs, 0).map(Val::I32) + } + } + } + + /// Process a STASH statement. + fn stash(&mut self, var: &Var) { + match *var { + Var::I16(n) => self.spot[n].stash(), + Var::I32(n) => self.twospot[n].stash(), + Var::A16(n, _) => self.tail[n].stash(), + Var::A32(n, _) => self.hybrid[n].stash(), + } + } + + /// Process a RETRIEVE statement. + fn retrieve(&mut self, var: &Var) -> Res<()> { + match *var { + Var::I16(n) => self.spot[n].retrieve(0), + Var::I32(n) => self.twospot[n].retrieve(0), + Var::A16(n, _) => self.tail[n].retrieve(0), + Var::A32(n, _) => self.hybrid[n].retrieve(0), + } + } + + /// Process an IGNORE or REMEMBER statement. Cannot fail. + fn set_rw(&mut self, var: &Var, rw: bool) { + match *var { + Var::I16(n) => self.spot[n].rw = rw, + Var::I32(n) => self.twospot[n].rw = rw, + Var::A16(n, _) => self.tail[n].rw = rw, + Var::A32(n, _) => self.hybrid[n].rw = rw, + } + } + + /// P()rocess an ABSTAIN or REINSTATE statement. Cannot fail. + fn abstain(&mut self, what: &ast::Abstain, f: &Fn(u32) -> u32) { + if let &ast::Abstain::Label(lbl) = what { + let idx = self.program.labels[&lbl] as usize; + if self.program.stmts[idx].body != StmtBody::GiveUp { + self.abstain[idx] = f(self.abstain[idx]); + } + } else { + for (i, stype) in self.program.stmt_types.iter().enumerate() { + if stype == what { + self.abstain[i] = f(self.abstain[i]); + } + } + } + } + + /// Array readout helper. + fn array_readout(&mut self, var: &Var) -> Res<()> { + let state = &mut self.last_out; + match *var { + Var::A16(n, _) => self.tail[n].readout(self.stdout, state, 0), + Var::A32(n, _) => self.hybrid[n].readout(self.stdout, state, 0), + _ => return IE994.err(), + } + } + + /// Array writein helper. + fn array_writein(&mut self, var: &Var) -> Res<()> { + let state = &mut self.last_in; + match *var { + Var::A16(n, _) => self.tail[n].writein(state, 0), + Var::A32(n, _) => self.hybrid[n].writein(state, 0), + _ => return IE994.err(), + } + } + + /// Debug helpers. + fn dump_state(&self) { + self.dump_state_one(&self.spot, "."); + self.dump_state_one(&self.twospot, ":"); + self.dump_state_one(&self.tail, ","); + self.dump_state_one(&self.hybrid, ";"); + if self.jumps.len() > 0 { + println!("Next stack: {:?}", self.jumps); + } + //println!("Abstained: {:?}", self.abstain); + } + + fn dump_state_one<T: Debug + Display>(&self, vec: &Vec<Bind<T>>, sigil: &str) { + if vec.len() > 0 { + for (i, v) in vec.iter().enumerate() { + print!("{}{} = {}, ", sigil, i, v); + } + println!(""); + } + } +} |