deleted arena allocator for the tree

This commit is contained in:
Lilith Schier 2026-08-11 17:43:53 +02:00
parent b437cefe5c
commit 25d72e9633
5 changed files with 115 additions and 158 deletions

View file

@ -1,68 +1,68 @@
use anyhow::bail;
use id_arena::Arena;
use rand::{Rng, RngExt};
use std::fmt::Write;
#[derive(Debug)]
pub struct Expression {
pub(crate) arena: Arena<AstNode>,
pub(crate) root: AstNodeId,
}
pub type AstNodeId = id_arena::Id<AstNode>;
pub type ExpBox = Box<Expression>;
#[derive(Debug, PartialEq, Clone)]
pub enum AstNode {
pub enum Expression {
Const(f64),
Dice(DiceFormula),
Neg(AstNodeId),
Add(AstNodeId, AstNodeId),
Sub(AstNodeId, AstNodeId),
Mul(AstNodeId, AstNodeId),
Div(AstNodeId, AstNodeId),
Neg(ExpBox),
Add(ExpBox, ExpBox),
Sub(ExpBox, ExpBox),
Mul(ExpBox, ExpBox),
Div(ExpBox, ExpBox),
}
#[derive(Debug, PartialEq, Clone)]
pub struct DiceFormula {
pub(crate) count: Option<AstNodeId>,
pub(crate) size: AstNodeId,
pub(crate) kh: Option<AstNodeId>,
pub(crate) kl: Option<AstNodeId>,
pub(crate) dh: Option<AstNodeId>,
pub(crate) dl: Option<AstNodeId>,
pub(crate) count: Option<ExpBox>,
pub(crate) size: ExpBox,
pub(crate) kh: Option<ExpBox>,
pub(crate) kl: Option<ExpBox>,
pub(crate) dh: Option<ExpBox>,
pub(crate) dl: Option<ExpBox>,
pub(crate) x: bool,
}
pub enum CompareFragment {
Eq(ExpBox),
Gt(ExpBox),
Gte(ExpBox),
Lt(ExpBox),
Lte(ExpBox),
}
const DICE_POOL_LIMIT: usize = 100_000;
impl Expression {
pub fn evaluate(&self, mut rng: impl Rng) -> anyhow::Result<String> {
pub fn collect_evaluation(&self, mut rng: impl Rng) -> anyhow::Result<String> {
let mut result = String::new();
let total = self.node_evaluate(&mut rng, self.root, &mut result, 100)?;
let total = self.evaluate(&mut rng, &mut result, 100)?;
Ok(format!("**{total}** = {result}"))
}
pub fn average(&self, rng: &mut impl Rng) -> anyhow::Result<f64> {
if let Ok(avg) = self.node_average(self.root) {
if let Ok(avg) = self.avg() {
return Ok(avg);
}
let mut average = self.node_sample(rng, self.root)?;
let mut average = self.sample(rng)?;
for idx in 1..3000 {
average =
(average * idx as f64 + self.node_sample(rng, self.root)?) / (idx as f64 + 1f64);
(average * idx as f64 + self.sample(rng)?) / (idx as f64 + 1f64);
}
Ok(average)
}
fn node_evaluate(
fn evaluate(
&self,
rng: &mut impl Rng,
node_id: AstNodeId,
output: &mut String,
outer_precedence: i64,
) -> anyhow::Result<f64> {
use AstNode::*;
let node = &self.arena[node_id];
use Expression::*;
let node = self;
let precedence = node.precedence();
let needs_parens = precedence > outer_precedence;
if needs_parens {
@ -83,7 +83,7 @@ impl Expression {
x,
}) => {
let count = if let Some(count_node) = count_node {
self.node_evaluate(rng, *count_node, output, precedence)? as usize
count_node.evaluate(rng, output, precedence)? as usize
} else {
1
};
@ -91,7 +91,7 @@ impl Expression {
bail!("Too many dice.")
};
output.push_str("d");
let size = self.node_evaluate(rng, *size_node, output, precedence)? as i64;
let size = size_node.evaluate(rng, output, precedence)? as i64;
if size < 1 {
bail!("Invalid die size.")
}
@ -114,27 +114,27 @@ impl Expression {
}
}
let kh = if let Some(id) = kh {
let kh = if let Some(child) = kh {
output.push_str("kh");
Some(self.node_evaluate(rng, *id, output, precedence)? as usize)
Some(child.evaluate(rng, output, precedence)? as usize)
} else {
None
};
let kl = if let Some(id) = kl {
let kl = if let Some(child) = kl {
output.push_str("kl");
Some(self.node_evaluate(rng, *id, output, precedence)? as usize)
Some(child.evaluate(rng, output, precedence)? as usize)
} else {
None
};
let dh = if let Some(id) = dh {
let dh = if let Some(child) = dh {
output.push_str("dh");
Some(self.node_evaluate(rng, *id, output, precedence)? as usize)
Some(child.evaluate(rng, output, precedence)? as usize)
} else {
None
};
let dl = if let Some(id) = dl {
let dl = if let Some(child) = dl {
output.push_str("dl");
Some(self.node_evaluate(rng, *id, output, precedence)? as usize)
Some(child.evaluate(rng, output, precedence)? as usize)
} else {
None
};
@ -201,31 +201,31 @@ impl Expression {
}
Neg(inner_node) => {
output.push_str("-");
let inner = self.node_evaluate(rng, *inner_node, output, precedence)?;
let inner = inner_node.evaluate(rng, output, precedence)?;
-inner
}
Add(lhs_node, rhs_node) => {
let lhs = self.node_evaluate(rng, *lhs_node, output, precedence)?;
let lhs = lhs_node.evaluate(rng, output, precedence)?;
output.push_str(" + ");
let rhs = self.node_evaluate(rng, *rhs_node, output, precedence)?;
let rhs = rhs_node.evaluate(rng, output, precedence)?;
lhs + rhs
}
Sub(lhs_node, rhs_node) => {
let lhs = self.node_evaluate(rng, *lhs_node, output, precedence)?;
let lhs = lhs_node.evaluate(rng, output, precedence)?;
output.push_str(" - ");
let rhs = self.node_evaluate(rng, *rhs_node, output, precedence)?;
let rhs = rhs_node.evaluate(rng, output, precedence)?;
lhs - rhs
}
Mul(lhs_node, rhs_node) => {
let lhs = self.node_evaluate(rng, *lhs_node, output, precedence)?;
let lhs = lhs_node.evaluate(rng, output, precedence)?;
output.push_str(" × ");
let rhs = self.node_evaluate(rng, *rhs_node, output, precedence)?;
let rhs = rhs_node.evaluate(rng, output, precedence)?;
lhs * rhs
}
Div(lhs_node, rhs_node) => {
let lhs = self.node_evaluate(rng, *lhs_node, output, precedence)?;
let lhs = lhs_node.evaluate(rng, output, precedence)?;
output.push_str(" ÷ ");
let rhs = self.node_evaluate(rng, *rhs_node, output, precedence)?;
let rhs = rhs_node.evaluate(rng, output, precedence)?;
lhs / rhs
}
};
@ -235,11 +235,11 @@ impl Expression {
Ok(result)
}
fn node_sample(&self, rng: &mut impl Rng, node_id: AstNodeId) -> anyhow::Result<f64> {
let node = &self.arena[node_id];
fn sample(&self, rng: &mut impl Rng) -> anyhow::Result<f64> {
let node = self;
let result = match node {
AstNode::Const(x) => *x,
AstNode::Dice(DiceFormula {
Expression::Const(x) => *x,
Expression::Dice(DiceFormula {
count,
size,
kh,
@ -249,14 +249,14 @@ impl Expression {
x,
}) => {
let count = if let Some(count) = count {
self.node_sample(rng, *count)? as usize
count.sample(rng)? as usize
} else {
1
};
if count > DICE_POOL_LIMIT {
bail!("Too many dice.")
};
let size = self.node_sample(rng, *size)? as i64;
let size = size.sample(rng)? as i64;
if size < 1 {
bail!("Invalid die size.")
}
@ -279,23 +279,23 @@ impl Expression {
}
rolls.sort();
let kh = if let Some(id) = kh {
self.node_sample(rng, *id)? as usize
let kh = if let Some(child) = kh {
child.sample(rng)? as usize
} else {
rolls.len()
};
let kl = if let Some(id) = kl {
self.node_sample(rng, *id)? as usize
let kl = if let Some(child) = kl {
child.sample(rng)? as usize
} else {
rolls.len()
};
let dh = if let Some(id) = dh {
self.node_sample(rng, *id)? as usize
let dh = if let Some(child) = dh {
child.sample(rng)? as usize
} else {
0
};
let dl = if let Some(id) = dl {
self.node_sample(rng, *id)? as usize
let dl = if let Some(child) = dl {
child.sample(rng)? as usize
} else {
0
};
@ -308,20 +308,20 @@ impl Expression {
.map(|x| x as f64)
.sum::<f64>()
}
AstNode::Neg(id) => -self.node_sample(rng, *id)?,
AstNode::Add(lhs, rhs) => self.node_sample(rng, *lhs)? + self.node_sample(rng, *rhs)?,
AstNode::Sub(lhs, rhs) => self.node_sample(rng, *lhs)? - self.node_sample(rng, *rhs)?,
AstNode::Mul(lhs, rhs) => self.node_sample(rng, *lhs)? * self.node_sample(rng, *rhs)?,
AstNode::Div(lhs, rhs) => self.node_sample(rng, *lhs)? / self.node_sample(rng, *rhs)?,
Expression::Neg(id) => -id.sample(rng)?,
Expression::Add(lhs, rhs) => lhs.sample(rng)? + rhs.sample(rng)?,
Expression::Sub(lhs, rhs) => lhs.sample(rng)? - rhs.sample(rng)?,
Expression::Mul(lhs, rhs) => lhs.sample(rng)? * rhs.sample(rng)?,
Expression::Div(lhs, rhs) => lhs.sample(rng)? / rhs.sample(rng)?,
};
Ok(result)
}
fn node_average(&self, node_id: AstNodeId) -> anyhow::Result<f64> {
let node = &self.arena[node_id];
fn avg(&self) -> anyhow::Result<f64> {
let node = self;
let result = match node {
AstNode::Const(x) => *x,
AstNode::Dice(DiceFormula {
Expression::Const(x) => *x,
Expression::Dice(DiceFormula {
count,
size,
kh,
@ -331,14 +331,14 @@ impl Expression {
x,
}) => {
let count = if let Some(count) = count {
self.node_average(*count)? as usize
count.avg()? as usize
} else {
1
};
if count > 1_000_000 {
bail!("Too many dice.")
};
let size = self.node_average(*size)? as i64;
let size = size.avg()? as i64;
if size < 1 {
bail!("Invalid die size.")
}
@ -361,19 +361,19 @@ impl Expression {
count as f64 * (size as f64 + 1f64) * 0.5
}
AstNode::Neg(id) => -self.node_average(*id)?,
AstNode::Add(lhs, rhs) => self.node_average(*lhs)? + self.node_average(*rhs)?,
AstNode::Sub(lhs, rhs) => self.node_average(*lhs)? - self.node_average(*rhs)?,
AstNode::Mul(lhs, rhs) => self.node_average(*lhs)? * self.node_average(*rhs)?,
AstNode::Div(lhs, rhs) => self.node_average(*lhs)? / self.node_average(*rhs)?,
Expression::Neg(child) => -child.avg()?,
Expression::Add(lhs, rhs) => lhs.avg()? + rhs.avg()?,
Expression::Sub(lhs, rhs) => lhs.avg()? - rhs.avg()?,
Expression::Mul(lhs, rhs) => lhs.avg()? * rhs.avg()?,
Expression::Div(lhs, rhs) => lhs.avg()? / rhs.avg()?,
};
Ok(result)
}
}
impl AstNode {
impl Expression {
fn precedence(&self) -> i64 {
use AstNode::*;
use Expression::*;
match self {
Const(_) => 1,
Dice { .. } => 2,