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case_match_expression split out into its own method

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greg 2018-10-18 01:49:42 -07:00
parent 40ccea8c05
commit f2282f0101
1 changed files with 49 additions and 44 deletions
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93
schala-lang/language/src/eval.rs
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@ -7,7 +7,7 @@ use std::io;
use itertools::Itertools;
use util::ScopeStack;
use reduced_ast::{ReducedAST, Stmt, Expr, Lit, Func};
use reduced_ast::{ReducedAST, Stmt, Expr, Lit, Func, Alternative};
use symbol_table::{SymbolSpec, Symbol, SymbolTable};
pub struct State<'a> {
@ -193,49 +193,7 @@ impl<'a> State<'a> {
Conditional { box cond, then_clause, else_clause } => self.conditional(cond, then_clause, else_clause),
Assign { box val, box expr } => self.assign_expression(val, expr),
Unit => Ok(Node::Expr(Unit)),
CaseMatch { box cond, alternatives } => match self.expression(Node::Expr(cond))? {
Node::PrimObject { name, tag, items } => {
for alt in alternatives {
if alt.tag.map(|t| t == tag).unwrap_or(true) {
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() });
}
}
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)
}
}
return Err(format!("PrimObject failed pattern match"));
},
Node::PrimTuple { .. } => Err(format!("Tuples not implemented")), //TODO make a distinction between not yet implemented and an actual runtime error
Node::Expr(e) => {
for alt in alternatives {
match (alt.guard, alt.tag) {
(Some(ref guard_expr), None) => {
match self.expression(guard_expr.clone().to_node())? {
Node::Expr(Expr::Lit(::reduced_ast::Lit::Bool(true))) =>
return self.block(alt.item),
_ => continue,
}
},
(None, None) => return self.block(alt.item),
_ => return Err(format!("Shouldn't match an expr against a pattern"))
}
}
return Err(format!("Expr Failed pattern match"));
}
},
CaseMatch { box cond, alternatives } => self.case_match_expression(cond, alternatives),
UnimplementedSigilValue => Err(format!("Sigil value eval not implemented"))
}
}
@ -393,6 +351,53 @@ impl<'a> State<'a> {
Ok(Node::Expr(Expr::Unit))
}
fn case_match_expression(&mut self, cond: Expr, alternatives: Vec<Alternative>) -> EvalResult<Node> {
match self.expression(Node::Expr(cond))? {
Node::PrimObject { name, tag, items } => {
for alt in alternatives {
if alt.tag.map(|t| t == tag).unwrap_or(true) {
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() });
}
}
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)
}
}
return Err(format!("PrimObject failed pattern match"));
},
Node::PrimTuple { .. } => Err(format!("Tuples not implemented")), //TODO make a distinction between not yet implemented and an actual runtime error
Node::Expr(e) => {
for alt in alternatives {
match (alt.guard, alt.tag) {
(Some(ref guard_expr), None) => {
match self.expression(guard_expr.clone().to_node())? {
Node::Expr(Expr::Lit(::reduced_ast::Lit::Bool(true))) =>
return self.block(alt.item),
_ => continue,
}
},
(None, None) => return self.block(alt.item),
_ => return Err(format!("Shouldn't match an expr against a pattern"))
}
}
return Err(format!("Expr Failed pattern match"));
}
}
}
fn value(&mut self, name: Rc<String>) -> EvalResult<Node> {
use self::ValueEntry::*;
use self::Func::*;