Added side effect framework
This commit is contained in:
parent
47f4c25020
commit
8528c912bd
60
src/eval.rs
60
src/eval.rs
@ -1,6 +1,12 @@
|
||||
use std::collections::HashMap;
|
||||
use parser::{AST, ASTNode, Expression, Function};
|
||||
|
||||
#[derive(Debug)]
|
||||
enum SideEffect {
|
||||
Print(String),
|
||||
Bundle(Vec<SideEffect>),
|
||||
}
|
||||
|
||||
struct Varmap {
|
||||
map: HashMap<String, Expression>
|
||||
}
|
||||
@ -109,43 +115,52 @@ impl Evaluator {
|
||||
}
|
||||
|
||||
fn step(&mut self, node: ASTNode) -> ASTNode {
|
||||
self.reduce_astnode(node)
|
||||
let (new_node, side_effect) = self.reduce_astnode(node);
|
||||
if let Some(s) = side_effect {
|
||||
self.perform_side_effect(s);
|
||||
}
|
||||
new_node
|
||||
}
|
||||
|
||||
fn reduce_astnode(&mut self, node: ASTNode) -> ASTNode {
|
||||
fn perform_side_effect(&mut self, side_effect: SideEffect) {
|
||||
println!("lol doin' a side effect {:?}", side_effect);
|
||||
}
|
||||
|
||||
fn reduce_astnode(&mut self, node: ASTNode) -> (ASTNode, Option<SideEffect>) {
|
||||
use parser::ASTNode::*;
|
||||
match node {
|
||||
ExprNode(expr) => {
|
||||
if expr.is_reducible() {
|
||||
ExprNode(self.reduce_expr(expr))
|
||||
let (new_expr, side_effect) = self.reduce_expr(expr);
|
||||
(ExprNode(new_expr), side_effect)
|
||||
} else {
|
||||
ExprNode(expr)
|
||||
(ExprNode(expr), None)
|
||||
}
|
||||
},
|
||||
FuncNode(func) => {
|
||||
let fn_name = func.prototype.name.clone();
|
||||
self.add_function(fn_name, func);
|
||||
ExprNode(Expression::Null)
|
||||
(ExprNode(Expression::Null), None)
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
fn reduce_expr(&mut self, expression: Expression) -> Expression {
|
||||
fn reduce_expr(&mut self, expression: Expression) -> (Expression, Option<SideEffect>) {
|
||||
use parser::Expression::*;
|
||||
match expression {
|
||||
Null => Null,
|
||||
e@StringLiteral(_) => e,
|
||||
e@Number(_) => e,
|
||||
Null => (Null, None),
|
||||
e@StringLiteral(_) => (e, None),
|
||||
e@Number(_) => (e, None),
|
||||
Variable(var) => {
|
||||
match self.lookup_binding(var) {
|
||||
None => Null,
|
||||
Some(expr) => expr,
|
||||
None => (Null, None),
|
||||
Some(expr) => (expr, None),
|
||||
}
|
||||
},
|
||||
BinExp(op, box left, box right) => {
|
||||
if right.is_reducible() {
|
||||
let new = self.reduce_expr(right);
|
||||
return BinExp(op, Box::new(left), Box::new(new));
|
||||
return (BinExp(op, Box::new(left), Box::new(new.0)), new.1);
|
||||
}
|
||||
|
||||
//special case for variable assignment
|
||||
@ -153,7 +168,7 @@ impl Evaluator {
|
||||
match left {
|
||||
Variable(var) => {
|
||||
self.add_binding(var, right);
|
||||
return Null;
|
||||
return (Null, None);
|
||||
},
|
||||
_ => ()
|
||||
}
|
||||
@ -161,9 +176,9 @@ impl Evaluator {
|
||||
|
||||
if left.is_reducible() {
|
||||
let new = self.reduce_expr(left);
|
||||
BinExp(op, Box::new(new), Box::new(right))
|
||||
(BinExp(op, Box::new(new.0), Box::new(right)), new.1)
|
||||
} else {
|
||||
self.reduce_binop(op, left, right) //can assume both arguments are maximally reduced
|
||||
(self.reduce_binop(op, left, right), None) //can assume both arguments are maximally reduced
|
||||
}
|
||||
},
|
||||
Call(name, args) => self.reduce_call(name, args),
|
||||
@ -206,15 +221,15 @@ impl Evaluator {
|
||||
}
|
||||
}
|
||||
|
||||
fn reduce_call(&mut self, name: String, arguments: Vec<Expression>) -> Expression {
|
||||
fn reduce_call(&mut self, name: String, arguments: Vec<Expression>) -> (Expression, Option<SideEffect>) {
|
||||
use parser::Expression::*;
|
||||
let function = match self.lookup_function(name) {
|
||||
Some(func) => func,
|
||||
None => return Null
|
||||
None => return (Null, None)
|
||||
};
|
||||
|
||||
if function.prototype.parameters.len() != arguments.len() {
|
||||
return Null
|
||||
return (Null, None)
|
||||
}
|
||||
|
||||
let mut frame: Varmap = Varmap::new();
|
||||
@ -224,14 +239,19 @@ impl Evaluator {
|
||||
|
||||
self.frames.push(frame);
|
||||
let mut retval = Null;
|
||||
let mut side_effects = Vec::new();
|
||||
for expr in function.body.iter() {
|
||||
retval = expr.clone();
|
||||
while retval.is_reducible() {
|
||||
retval = self.reduce_expr(retval);
|
||||
let r = self.reduce_expr(retval);
|
||||
retval = r.0;
|
||||
if let Some(s) = r.1 {
|
||||
side_effects.push(s);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
self.frames.pop();
|
||||
retval
|
||||
(retval, Some(SideEffect::Bundle(side_effects)))
|
||||
}
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user