init
This commit is contained in:
commit
f8a8727fdd
GPG Key ID:
E81D8382DC2F971B
56
Cargo.lock
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56
Cargo.lock
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@ -0,0 +1,56 @@
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# This file is automatically @generated by Cargo.
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# It is not intended for manual editing.
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[[package]]
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name = "derive_more"
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version = "0.99.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
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"quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
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"syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "eq"
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version = "0.1.0"
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dependencies = [
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"derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "proc-macro2"
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version = "1.0.6"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "quote"
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version = "1.0.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "syn"
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version = "1.0.8"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
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"quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
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"unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "unicode-xid"
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version = "0.2.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[metadata]
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"checksum derive_more 0.99.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2159be042979966de68315bce7034bb000c775f22e3e834e1c52ff78f041cae8"
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"checksum proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "9c9e470a8dc4aeae2dee2f335e8f533e2d4b347e1434e5671afc49b054592f27"
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"checksum quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "053a8c8bcc71fcce321828dc897a98ab9760bef03a4fc36693c231e5b3216cfe"
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"checksum syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "661641ea2aa15845cddeb97dad000d22070bb5c1fb456b96c1cba883ec691e92"
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"checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
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10
Cargo.toml
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10
Cargo.toml
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[package]
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name = "eq"
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version = "0.1.0"
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authors = ["shimun <shimun@shimun.net>"]
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edition = "2018"
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# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
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[dependencies]
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derive_more = "0.99.2"
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211
src/main.rs
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211
src/main.rs
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extern crate derive_more;
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use derive_more::Display;
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use std::collections::HashMap;
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use std::fmt;
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use std::iter::successors;
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#[derive(Clone)]
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struct Context {
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vars: HashMap<String, f64>,
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}
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impl Context {
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fn get(&self, name: &str) -> Option<f64> {
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return self.vars.get(name).cloned();
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}
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fn with(&self, name: String, value: f64) -> Context {
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let mut n = self.clone();
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n.vars.insert(name, value);
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n
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}
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}
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trait Eval: Derive + fmt::Display {
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fn eval(&self, ctx: &Context) -> f64;
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fn boxed_clone(&self) -> Box<dyn Eval>;
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}
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trait Derive {
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fn derive(&self) -> Value;
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}
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#[derive(Display)]
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enum Value {
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#[display(fmt = "{}", _0)]
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Const(f64),
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#[display(fmt = "{}", _0)]
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Eval(Box<dyn Eval>),
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}
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impl Clone for Value {
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fn clone(&self) -> Self {
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match self {
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Self::Const(c) => Self::Const(*c),
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Self::Eval(e) => Self::Eval(e.boxed_clone()),
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}
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}
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}
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impl Derive for Value {
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fn derive(&self) -> Value {
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match self {
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Self::Const(_) => Value::Const(0.0),
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Self::Eval(e) => e.derive(),
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}
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}
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}
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impl Eval for Value {
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fn eval(&self, ctx: &Context) -> f64 {
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match self {
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Self::Const(c) => *c,
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Self::Eval(e) => e.eval(&ctx),
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}
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}
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fn boxed_clone(&self) -> Box<dyn Eval> {
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Box::new(self.clone())
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}
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}
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#[derive(Clone, Display)]
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#[display(fmt = "`{}`", _0)]
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struct Var(String);
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impl Eval for Var {
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fn eval(&self, ctx: &Context) -> f64 {
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ctx.get(&self.0).unwrap()
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}
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fn boxed_clone(&self) -> Box<dyn Eval> {
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Box::new(self.clone())
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}
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}
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impl Derive for Var {
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fn derive(&self) -> Value {
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Value::Const(1.0)
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}
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}
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impl Into<Value> for Var {
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fn into(self) -> Value {
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Value::Eval(Box::new(self))
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}
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}
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impl Var {
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fn new<T: Into<String>>(name: T) -> Self {
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Var(name.into())
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}
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fn val<T: Into<String>>(name: T) -> Value {
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Self::new(name).into()
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}
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}
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#[derive(Clone, Display)]
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enum Op {
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#[display(fmt = "{} * {}", _0, _1)]
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Mul(Value, Value),
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#[display(fmt = "{} /({})", _0, _1)]
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Div(Value, Value),
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#[display(fmt = "{} + {}", _0, _1)]
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Add(Value, Value),
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#[display(fmt = "{} - {}", _0, _1)]
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Sub(Value, Value),
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#[display(fmt = "{}**({})", _0, _1)]
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Pow(Value, Value),
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}
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impl Eval for Op {
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fn eval(&self, ctx: &Context) -> f64 {
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match self {
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Self::Mul(a, b) => a.eval(ctx) * b.eval(ctx),
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Self::Div(a, b) => a.eval(ctx) / b.eval(ctx),
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Self::Add(a, b) => a.eval(ctx) + b.eval(ctx),
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Self::Sub(a, b) => a.eval(ctx) - b.eval(ctx),
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Self::Pow(a, b) => a.eval(ctx).powf(b.eval(ctx)),
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}
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}
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fn boxed_clone(&self) -> Box<dyn Eval> {
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Box::new(self.clone())
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}
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}
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impl Derive for Op {
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fn derive(&self) -> Value {
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match self {
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Self::Mul(a, b) => Op::Add(
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Op::Mul(a.derive(), b.clone()).into(),
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Op::Mul(a.clone(), b.derive()).into(),
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),
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Self::Div(a, b) => Op::Div(
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Op::Sub(
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Op::Mul(a.derive(), b.clone()).into(),
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Op::Mul(a.clone(), b.derive()).into(),
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)
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.into(),
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Op::Pow(b.clone(), Value::Const(2.0)).into(),
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),
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Self::Add(a, b) => Op::Add(a.derive(), b.derive()),
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Self::Sub(a, b) => Op::Sub(a.derive(), b.derive()),
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Self::Pow(a, b) => Op::Pow(
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Op::Mul(a.clone(), b.clone()).into(),
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Op::Sub(b.clone(), Value::Const(1.0)).into(),
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),
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}
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.into()
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}
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}
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impl Into<Value> for Op {
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fn into(self) -> Value {
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Value::Eval(Box::new(self))
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}
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}
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fn newton_raphson<'a>(eq: &'a dyn Eval, x0: f64) -> impl Iterator<Item = f64> + 'a {
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//xp - f(x)/f'(x)
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let d = eq.derive();
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let eq = eq.clone();
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let mut i = 0;
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successors(Some(x0), move |xp: &f64| -> Option<f64> {
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let ctx = Context {
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vars: vec![("x".to_string(), *xp)].into_iter().collect(),
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};
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let calc = Op::Sub(
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Var::val("x"),
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Op::Div(Value::Eval(eq.boxed_clone()), d.clone()).into(),
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);
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println!("( {}.) {} -> {}\n", &i, &calc, &xp);
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i += 1;
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Some(calc.eval(&ctx)).filter(|x| (x - xp).abs() > (10.0f64).powf(-8.0))
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})
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}
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fn n_root(number: f64, n: f64) -> Option<f64> {
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let eq: Value = Op::Sub(
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Op::Pow(Var::val("x"), Value::Const(n).into()).into(),
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Value::Const(number),
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)
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.into();
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newton_raphson(&eq, 1.0).last()
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}
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fn main() {
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let ctx = Context {
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vars: vec![("x".to_string(), 5.0)].into_iter().collect(),
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};
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let eq = Op::Sub(
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Op::Add(
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Op::Pow(Value::Const(3.0), Var::val("x")).into(),
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Op::Pow(Value::Const(9.0), Var::val("x")).into(),
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)
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.into(),
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Op::Pow(Value::Const(4.0), Var::val("x")).into(),
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);
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let eq: Value = Op::Sub(
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Op::Pow(Var::val("x"), Value::Const(2.0).into()).into(),
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Value::Const(9.0),
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)
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.into();
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let res = n_root(9.0, 2.0);
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println!("1.0 - {}/{} ==> {}", &eq, eq.derive(), res.unwrap());
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}
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