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Starting on pattern-matching tuples

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Lots of duplicated code here
This commit is contained in:
greg 2018-11-05 03:17:03 -08:00
parent bada386979
commit 62043ac2d1
1 changed files with 43 additions and 11 deletions
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54
schala-lang/language/src/eval.rs
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@ -72,6 +72,12 @@ impl Node {
Node::PrimTuple { items } => format!("{}", paren_wrapped_vec(items.iter().map(|x| x.to_repl()))),
}
}
fn is_true(&self) -> bool {
match self {
Node::Expr(Expr::Lit(::reduced_ast::Lit::Bool(true))) => true,
_ => false,
}
}
}
#[derive(Debug)]
@ -372,16 +378,16 @@ impl<'a> State<'a> {
fn case_match_expression(&mut self, cond: Expr, alternatives: Vec<Alternative>) -> EvalResult<Node> {
let cond = self.expression(Node::Expr(cond))?;
for alt in alternatives {
println!("ALT: {:?}", alt);
println!("ALTERNATIVE: {:?}", alt);
// no matter what type of condition we have, ignore alternative if the guard evaluates false
if let Some(ref guard_expr) = alt.guard {
let guard_expr = match &cond {
Node::Expr(ref e) => guard_expr.clone().replace_conditional_target_sigil(e),
_ => guard_expr.clone()
};
match self.expression(guard_expr.to_node())? {
Node::Expr(Expr::Lit(::reduced_ast::Lit::Bool(true))) => (),
_ => continue,
if !self.expression(guard_expr.to_node())?.is_true() {
continue;
}
}
@ -398,17 +404,43 @@ impl<'a> State<'a> {
}
}
if let Some(guard_expr) = alt.guard {
let evaled_guard = inner_state.expression(guard_expr.to_node());
println!("EVALED GUARD: {:?}", evaled_guard);
//continue
}
return inner_state.block(alt.item)
}
},
Node::PrimTuple { ref items } => {
return Err(format!("Prim tuple not done"))
if items.len() != alt.subpatterns.len() {
return Err(format!("Subpattern length isn't correct"));
}
let mut inner_state = State {
values: self.values.new_scope(None),
symbol_table_handle: self.symbol_table_handle.clone(),
};
for (bound_var, val) in alt.bound_vars.iter().zip(items.iter()) {
if let Some(bv) = bound_var.as_ref() {
inner_state.values.insert(bv.clone(), ValueEntry::Binding { constant: true, val: val.clone() });
}
}
let mut passes = true;
for (maybe_subp, cond) in alt.subpatterns.iter().zip(items.iter()) {
if let Some(subp) = maybe_subp {
if let Some(ref guard) = subp.guard {
let guard_expr = match &cond {
Node::Expr(ref e) => guard.clone().replace_conditional_target_sigil(e),
_ => guard.clone()
};
if !inner_state.expression(guard_expr.to_node())?.is_true() {
passes = false;
break;
}
}
}
}
if !passes {
continue;
}
return inner_state.block(alt.item)
},
Node::Expr(ref _e) => {
if let None = alt.tag {