1
0
mirror of https://github.com/osmarks/osmarkscalculator.git synced 2024-10-30 03:26:16 +00:00

web build

This commit is contained in:
osmarks 2023-11-28 16:47:17 +00:00
parent b8eddc0837
commit 6e10a5f84b
7 changed files with 930 additions and 709 deletions

4
.gitignore vendored
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@ -1,4 +1,6 @@
/target /target
osmarkscalculator.zip osmarkscalculator.zip
osmarkscalculator.tar osmarkscalculator.tar
src.zip src.zip
dist
vgcore*

230
Cargo.lock generated
View File

@ -9,10 +9,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "61604a8f862e1d5c3229fdd78f8b02c68dcf73a4c4b05fd636d12240aaa242c1" checksum = "61604a8f862e1d5c3229fdd78f8b02c68dcf73a4c4b05fd636d12240aaa242c1"
[[package]] [[package]]
name = "autocfg" name = "bumpalo"
version = "1.0.1" version = "3.11.1"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a" checksum = "572f695136211188308f16ad2ca5c851a712c464060ae6974944458eb83880ba"
[[package]]
name = "cfg-if"
version = "0.1.10"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
[[package]] [[package]]
name = "cfg-if" name = "cfg-if"
@ -20,65 +26,12 @@ version = "1.0.0"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd" checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
[[package]]
name = "crossbeam-channel"
version = "0.5.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e54ea8bc3fb1ee042f5aace6e3c6e025d3874866da222930f70ce62aceba0bfa"
dependencies = [
"cfg-if",
"crossbeam-utils",
]
[[package]]
name = "crossbeam-deque"
version = "0.8.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "6455c0ca19f0d2fbf751b908d5c55c1f5cbc65e03c4225427254b46890bdde1e"
dependencies = [
"cfg-if",
"crossbeam-epoch",
"crossbeam-utils",
]
[[package]]
name = "crossbeam-epoch"
version = "0.9.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "97242a70df9b89a65d0b6df3c4bf5b9ce03c5b7309019777fbde37e7537f8762"
dependencies = [
"cfg-if",
"crossbeam-utils",
"lazy_static",
"memoffset",
"scopeguard",
]
[[package]]
name = "crossbeam-utils"
version = "0.8.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "cfcae03edb34f947e64acdb1c33ec169824e20657e9ecb61cef6c8c74dcb8120"
dependencies = [
"cfg-if",
"lazy_static",
]
[[package]] [[package]]
name = "either" name = "either"
version = "1.6.1" version = "1.6.1"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457" checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
[[package]]
name = "hermit-abi"
version = "0.1.19"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
dependencies = [
"libc",
]
[[package]] [[package]]
name = "inlinable_string" name = "inlinable_string"
version = "0.1.14" version = "0.1.14"
@ -94,36 +47,32 @@ dependencies = [
"either", "either",
] ]
[[package]]
name = "lazy_static"
version = "1.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
[[package]] [[package]]
name = "libc" name = "libc"
version = "0.2.114" version = "0.2.137"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b0005d08a8f7b65fb8073cb697aa0b12b631ed251ce73d862ce50eeb52ce3b50" checksum = "fc7fcc620a3bff7cdd7a365be3376c97191aeaccc2a603e600951e452615bf89"
[[package]] [[package]]
name = "memoffset" name = "log"
version = "0.6.5" version = "0.4.17"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce" checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
dependencies = [ dependencies = [
"autocfg", "cfg-if 1.0.0",
] ]
[[package]] [[package]]
name = "num_cpus" name = "memory_units"
version = "1.13.1" version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "19e64526ebdee182341572e50e9ad03965aa510cd94427a4549448f285e957a1" checksum = "8452105ba047068f40ff7093dd1d9da90898e63dd61736462e9cdda6a90ad3c3"
dependencies = [
"hermit-abi", [[package]]
"libc", name = "once_cell"
] version = "1.16.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "86f0b0d4bf799edbc74508c1e8bf170ff5f41238e5f8225603ca7caaae2b7860"
[[package]] [[package]]
name = "osmarkscalculator" name = "osmarkscalculator"
@ -132,36 +81,129 @@ dependencies = [
"anyhow", "anyhow",
"inlinable_string", "inlinable_string",
"itertools", "itertools",
"rayon", "wasm-bindgen",
"wee_alloc",
] ]
[[package]] [[package]]
name = "rayon" name = "proc-macro2"
version = "1.5.1" version = "1.0.47"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "c06aca804d41dbc8ba42dfd964f0d01334eceb64314b9ecf7c5fad5188a06d90" checksum = "5ea3d908b0e36316caf9e9e2c4625cdde190a7e6f440d794667ed17a1855e725"
dependencies = [ dependencies = [
"autocfg", "unicode-ident",
"crossbeam-deque",
"either",
"rayon-core",
] ]
[[package]] [[package]]
name = "rayon-core" name = "quote"
version = "1.9.1" version = "1.0.21"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "d78120e2c850279833f1dd3582f730c4ab53ed95aeaaaa862a2a5c71b1656d8e" checksum = "bbe448f377a7d6961e30f5955f9b8d106c3f5e449d493ee1b125c1d43c2b5179"
dependencies = [ dependencies = [
"crossbeam-channel", "proc-macro2",
"crossbeam-deque",
"crossbeam-utils",
"lazy_static",
"num_cpus",
] ]
[[package]] [[package]]
name = "scopeguard" name = "syn"
version = "1.1.0" version = "1.0.103"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd" checksum = "a864042229133ada95abf3b54fdc62ef5ccabe9515b64717bcb9a1919e59445d"
dependencies = [
"proc-macro2",
"quote",
"unicode-ident",
]
[[package]]
name = "unicode-ident"
version = "1.0.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
name = "wasm-bindgen"
version = "0.2.83"
source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
"cfg-if 1.0.0",
"wasm-bindgen-macro",
]
[[package]]
name = "wasm-bindgen-backend"
version = "0.2.83"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "4c8ffb332579b0557b52d268b91feab8df3615f265d5270fec2a8c95b17c1142"
dependencies = [
"bumpalo",
"log",
"once_cell",
"proc-macro2",
"quote",
"syn",
"wasm-bindgen-shared",
]
[[package]]
name = "wasm-bindgen-macro"
version = "0.2.83"
source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
"quote",
"wasm-bindgen-macro-support",
]
[[package]]
name = "wasm-bindgen-macro-support"
version = "0.2.83"
source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
"proc-macro2",
"quote",
"syn",
"wasm-bindgen-backend",
"wasm-bindgen-shared",
]
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name = "wasm-bindgen-shared"
version = "0.2.83"
source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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"libc",
"memory_units",
"winapi",
]
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name = "winapi"
version = "0.3.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
"winapi-i686-pc-windows-gnu",
"winapi-x86_64-pc-windows-gnu",
]
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name = "winapi-i686-pc-windows-gnu"
version = "0.4.0"
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[[package]]
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View File

@ -3,10 +3,23 @@ name = "osmarkscalculator"
version = "0.1.0" version = "0.1.0"
edition = "2018" edition = "2018"
[lib]
crate-type = ["cdylib", "rlib"]
name = "osmarkscalculator"
[[bin]]
name = "osmarkscalculator"
path = "src/main.rs"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies] [dependencies]
anyhow = "1" anyhow = "1"
inlinable_string = "0.1" inlinable_string = "0.1"
rayon = "1.5" itertools = "0.10"
itertools = "0.10" wasm-bindgen = "0.2.63"
wee_alloc = "0.4.5"
[profile.release]
opt-level = "s"
lto = true

44
buildcalc.py Normal file
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@ -0,0 +1,44 @@
BINDING = """
let loaded = false
onmessage = async ev => {
if (!loaded) {
await wasm_bindgen("./osmarkscalculator.wasm")
loaded = true
}
var [fn, ...args] = ev.data
let init = false
if (fn === "deinit") {
wasm_bindgen.deinit_context()
init = false
} else if (fn === "run") {
const start = performance.now()
try {
if (!init) {
wasm_bindgen.init_context()
wasm_bindgen.load_defaults()
init = true;
}
postMessage(["ok", wasm_bindgen.run_program(args[0]), performance.now() - start])
} catch(e) {
postMessage(["error", e.toString(), performance.now() - start])
}
}
}
"""
HEADER = """
---
title: osmarkscalculator
description: Unholy horrors moved from the depths of my projects directory to your browser. Theoretically, this is a calculator. Good luck using it.
---
""".strip()
import subprocess, rjsmin, os, shutil
subprocess.run(["wasm-pack", "build", "--target=no-modules"])
minified = rjsmin.jsmin(open("pkg/osmarkscalculator.js", "r").read() + BINDING)
os.makedirs("dist", exist_ok=True)
subprocess.run(["wasm-opt", "-Oz", "pkg/osmarkscalculator_bg.wasm", "-o", "dist/osmarkscalculator.wasm"])
open("dist/osmarkscalculator.js", "w").write(minified)
with open("index.html") as f:
g = HEADER + f.read().replace("""<meta charset="UTF-8">""", "")
with open("dist/index.html", "w") as h:
h.write(g)
shutil.copytree("dist/.", "../website/experiments/osmarkscalculator", dirs_exist_ok=True)

72
index.html Normal file
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@ -0,0 +1,72 @@
<meta charset="UTF-8">
<textarea id="program" style="width: 100%; resize: vertical" rows="5"></textarea>
<pre id="output"></pre>
<button id="go">Go</button>
<button id="clear">Clear Context</button>
<select id="examples">
</select>
<script>
const examples = {
"blank": "",
"factorial": `Fac[n] = Fac[n-1]*n
Fac[0] = 1
Fac[17]
`,
"expand": "(a+b)*(c+d)*(e+f)*(g+h)",
"expand2": "(a+b)^3*(b+c)-d",
"fibonacci": `Fib[n] = Fib[n-1] + Fib[n-2]
Fib[0] = 0
Fib[1] = 1
Fib[6]
`,
"predicate": `IsEven[x] = 0
IsEven[x#Eq[Mod[x, 2], 0]] = 1
IsEven[3] - IsEven[4]`,
"derivative": `D[3*x^3 + 6*x, x]`,
"simplify": `x^a/x^(a+1)`,
"simplify2": "Negate[a+b] + b",
"arith": `(12+55)^3-75+16/(2*2)+5+3*4`,
"subst": "Subst[x=4, x+4+4+4+4]"
}
const examplesSelector = document.querySelector("#examples")
const program = document.querySelector("#program")
for (const name of Object.keys(examples)) {
const opt = document.createElement("option")
opt.value = name
opt.appendChild(document.createTextNode(name))
examplesSelector.appendChild(opt)
}
examplesSelector.addEventListener("change", () => {
program.value = examples[examplesSelector.value]
})
var worker = new Worker("osmarkscalculator.js")
const forceKill = () => {
console.warn("Force-terminating worker.")
worker.terminate()
worker = new Worker("osmarkscalculator.js")
}
const write = data => {
const out = document.querySelector("#output")
while (out.firstChild) { out.removeChild(out.firstChild) }
out.appendChild(document.createTextNode(data))
}
document.querySelector("#go").addEventListener("click", () => {
console.log(program.value)
write("Running...")
worker.postMessage(["run", program.value])
var timeout = setTimeout(() => {
forceKill()
write("Execution timeout")
}, 5000)
worker.onmessage = ev => {
const [status, result, time] = ev.data
if (status === "ok") {
write(result + `\nin ${time}ms`)
} else {
write("Internal error: " + result + `\nin ${time}ms`)
}
clearInterval(timeout)
}
})
document.querySelector("#clear").addEventListener("click", () => worker.postMessage(["deinit"]))
</script>

658
src/lib.rs Normal file
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@ -0,0 +1,658 @@
use anyhow::{Result, Context, bail};
use inlinable_string::InlinableString;
use std::collections::HashMap;
use std::borrow::Cow;
use std::convert::TryInto;
use std::sync::Arc;
use wasm_bindgen::prelude::*;
#[global_allocator]
static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
mod parse;
mod value;
mod util;
mod env;
use value::Value;
use env::{Rule, Ruleset, Env, Bindings, RuleResult, Operation};
// Main pattern matcher function;
fn match_and_bind(expr: &Value, rule: &Rule, env: &Env) -> Result<Option<Value>> {
fn go(expr: &Value, cond: &Value, env: &Env, already_bound: &Bindings) -> Result<Option<Bindings>> {
match (expr, cond) {
// numbers match themselves
(Value::Num(a), Value::Num(b)) => if a == b { Ok(Some(HashMap::new())) } else { Ok(None) },
// handle predicated value - check all predicates, succeed with binding if they match
(val, Value::Call(x, args)) if x == "#" => {
let preds = &args[1..];
let (mut success, mut bindings) = match go(val, &args[0], env, already_bound)? {
Some(bindings) => (true, bindings),
None => (false, already_bound.clone())
};
for pred in preds {
match pred {
// "Num" predicate matches successfully if something is a number
Value::Identifier(i) if i.as_ref() == "Num" => {
match val {
Value::Num(_) => (),
_ => success = false
}
},
// "Ident" does the same for idents
Value::Identifier(i) if i.as_ref() == "Ident" => {
match val {
Value::Identifier(_) => (),
_ => success = false
}
},
// Invert match success
Value::Identifier(i) if i.as_ref() == "Not" => {
success = !success
},
Value::Call(head, args) if head.as_ref() == "And" => {
// Try all patterns it's given, and if any fails then fail the match
for arg in args.iter() {
match go(val, arg, env, &bindings)? {
Some(new_bindings) => bindings.extend(new_bindings),
None => success = false
}
}
},
Value::Call(head, args) if head.as_ref() == "Eq" => {
// Evaluate all arguments and check if they are equal
let mut compare_against = None;
for arg in args.iter() {
let mut evaluated_value = arg.subst(&bindings);
run_rewrite(&mut evaluated_value, env).context("evaluating Eq predicate")?;
match compare_against {
Some(ref x) => if x != &evaluated_value {
success = false
},
None => compare_against = Some(evaluated_value)
}
}
},
Value::Call(head, args) if head.as_ref() == "Gte" => {
// Evaluate all arguments and do comparison.
let mut x = args[0].subst(&bindings);
let mut y = args[1].subst(&bindings);
run_rewrite(&mut x, env).context("evaluating Gte predicate")?;
run_rewrite(&mut y, env).context("evaluating Gte predicate")?;
success &= x >= y;
},
Value::Call(head, args) if head.as_ref() == "Or" => {
// Tries all patterns it's given and will set the match to successful if *any* of them works
for arg in args.iter() {
match go(val, arg, env, &bindings)? {
Some(new_bindings) => {
bindings.extend(new_bindings);
success = true
},
None => ()
}
}
},
_ => bail!("invalid predicate {:?}", pred)
}
}
Ok(match success {
true => Some(bindings),
false => None
})
},
(Value::Call(exp_head, exp_args), Value::Call(rule_head, rule_args)) => {
let mut exp_args = Cow::Borrowed(exp_args);
// Regardless of any special casing for associativity etc., different heads mean rules can never match
if exp_head != rule_head { return Ok(None) }
let op = env.get_op(exp_head);
// Copy bindings from the upper-level matching, so that things like "a+(b+a)" work.
let mut out_bindings = already_bound.clone();
// Special case for associative expressions: split off extra arguments into a new tree
if op.associative && rule_args.len() < exp_args.len() {
let exp_args = exp_args.to_mut();
let rest = exp_args.split_off(rule_args.len() - 1);
let rem = Value::Call(exp_head.clone(), rest);
exp_args.push(rem);
}
if rule_args.len() != exp_args.len() { return Ok(None) }
// Try and match all "adjacent" arguments to each other
for (rule_arg, exp_arg) in rule_args.iter().zip(&*exp_args) {
match go(exp_arg, rule_arg, env, &out_bindings)? {
Some(x) => out_bindings.extend(x),
None => return Ok(None)
}
}
Ok(Some(out_bindings))
},
// identifier pattern matches anything, unless the identifier has already been bound to something else
(x, Value::Identifier(a)) => {
if let Some(b) = already_bound.get(a) {
if b != x {
return Ok(None);
}
};
Ok(Some(vec![(a.clone(), x.clone())].into_iter().collect()))
},
// anything else doesn't match
_ => Ok(None)
}
}
// special case at top level of expression - try to match pattern to different subranges of input
match (expr, &rule.condition) {
// this only applies to matching one "call" against a "call" pattern (with same head)
(Value::Call(ehead, eargs), Value::Call(rhead, rargs)) => {
// and also only to associative operations
if env.get_op(ehead).associative && eargs.len() > rargs.len() && ehead == rhead {
// consider all possible subranges of the arguments of the appropriate length
for range_start in 0..=(eargs.len() - rargs.len()) {
// extract the arguments & convert into new Value
let c_args = eargs[range_start..range_start + rargs.len()].iter().cloned().collect();
let c_call = Value::Call(ehead.clone(), c_args);
// attempt to match the new subrange against the current rule
if let Some(r) = match_and_bind(&c_call, rule, env)? {
// generate new output with result
let mut new_args = Vec::with_capacity(3);
// add back extra start items
if range_start != 0 {
new_args.push(Value::Call(ehead.clone(), eargs[0..range_start].iter().cloned().collect()))
}
new_args.push(r);
// add back extra end items
if range_start + rargs.len() != eargs.len() {
new_args.push(Value::Call(ehead.clone(), eargs[range_start + rargs.len()..eargs.len()].iter().cloned().collect()))
}
let new_exp = Value::Call(ehead.clone(), new_args);
return Ok(Some(new_exp))
}
}
}
}
_ => ()
}
// substitute bindings from matching into either an intrinsic or the output of the rule
if let Some(bindings) = go(expr, &rule.condition, env, &HashMap::new())? {
Ok(Some(match &rule.result {
RuleResult::Intrinsic(id) => env.intrinsics.get(id).unwrap()(&bindings).with_context(|| format!("applying intrinsic {}", id))?,
RuleResult::Exp(e) => e.subst(&bindings)
}))
} else {
Ok(None)
}
}
// Sort any commutative expressions
fn canonical_sort(v: &mut Value, env: &Env) -> Result<()> {
match v {
Value::Call(head, args) => if env.get_op(head).commutative {
args.sort();
},
_ => ()
}
Ok(())
}
// Associative expression flattening.
fn flatten_tree(v: &mut Value, env: &Env) -> Result<()> {
match v {
Value::Call(head, args) => {
if env.get_op(head).associative {
// Not the most efficient algorithm, but does work.
// Repeatedly find the position of a flatten-able child node, and splice it into the argument list.
loop {
let mut move_pos = None;
for (i, child) in args.iter().enumerate() {
if let Some(child_head) = child.head() {
if *head == child_head {
move_pos = Some(i)
}
}
}
match move_pos {
Some(pos) => {
let removed = std::mem::replace(&mut args[pos], Value::Num(0));
// We know that removed will be a Call (because its head wasn't None earlier). Unfortunately, rustc does not know this.
match removed {
Value::Call(_, removed_child_args) => args.splice(pos..=pos, removed_child_args.into_iter()),
_ => unreachable!()
};
},
None => break
}
}
}
// Also do sorting after flattening, to avoid any weirdness with ordering.
canonical_sort(v, env)?;
return Ok(())
},
_ => return Ok(())
}
}
// Applies rewrite rulesets to an expression.
fn run_rewrite(v: &mut Value, env: &Env) -> Result<()> {
loop {
// Compare original and final hash instead of storing a copy of the original value and checking equality
// Collision probability is negligible and this is substantially faster than storing/comparing copies.
let original_hash = v.get_hash();
flatten_tree(v, env).context("flattening tree")?;
// Call expressions can be rewritten using pattern matching rules; identifiers can be substituted for bindings if available
match v {
Value::Call(head, args) => {
let head = head.clone();
// Rewrite sub-expressions using existing environment
args.iter_mut().try_for_each(|arg| run_rewrite(arg, env).with_context(|| format!("rewriting {}", arg.render_to_string(env))))?;
// Try to apply all applicable rules from all rulesets, in sequence
for ruleset in env.ruleset.iter() {
if let Some(rules) = ruleset.get(&head) {
// Within a ruleset, rules are applied backward. This is nicer for users using the program interactively.
for rule in rules.iter().rev() {
if let Some(result) = match_and_bind(v, rule, env).with_context(|| format!("applying rule {} -> {:?}", rule.condition.render_to_string(env), rule.result))? {
*v = result;
flatten_tree(v, env).context("flattening tree after rule application")?;
}
}
}
}
},
// Substitute in bindings which have been provided
Value::Identifier(ident) => {
match env.bindings.get(ident) {
Some(val) => {
*v = val.clone();
},
None => return Ok(())
}
},
_ => {
return Ok(())
}
}
if original_hash == v.get_hash() {
break
}
}
Ok(())
}
// Utility function for defining intrinsic functions for binary operators.
// Converts a function which does the actual operation to a function from bindings to a value.
fn wrap_binop<F: 'static + Fn(i128, i128) -> Result<i128> + Sync + Send>(op: F) -> Box<dyn Fn(&Bindings) -> Result<Value> + Sync + Send> {
Box::new(move |bindings: &Bindings| {
let a = bindings.get(&InlinableString::from("a")).context("binop missing first argument")?.assert_num("binop first argument")?;
let b = bindings.get(&InlinableString::from("b")).context("binop missing second argument")?.assert_num("binop second argument")?;
op(a, b).map(Value::Num)
})
}
// Provides a basic environment with operator commutativity/associativity operations and intrinsics.
fn make_initial_env() -> Env {
let mut ops = HashMap::new();
ops.insert(InlinableString::from("+"), Operation { commutative: true, associative: true });
ops.insert(InlinableString::from("*"), Operation { commutative: true, associative: true });
ops.insert(InlinableString::from("-"), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("/"), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("^"), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("="), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("#"), Operation { commutative: false, associative: true });
let ops = Arc::new(ops);
let mut intrinsics = HashMap::new();
intrinsics.insert(0, wrap_binop(|a, b| a.checked_add(b).context("integer overflow")));
intrinsics.insert(1, wrap_binop(|a, b| a.checked_sub(b).context("integer overflow")));
intrinsics.insert(2, wrap_binop(|a, b| a.checked_mul(b).context("integer overflow")));
intrinsics.insert(3, wrap_binop(|a, b| a.checked_div(b).context("division by zero")));
intrinsics.insert(4, wrap_binop(|a, b| {
// The "pow" function takes a usize (machine-sized unsigned integer) and an i128 may not fit into this, so an extra conversion is needed
Ok(a.pow(b.try_into()?))
}));
intrinsics.insert(5, Box::new(|bindings| {
// Substitute a single, given binding var=value into a target expression
let var = bindings.get(&InlinableString::from("var")).unwrap();
let value = bindings.get(&InlinableString::from("value")).unwrap();
let target = bindings.get(&InlinableString::from("target")).unwrap();
let name = var.assert_ident("Subst")?;
let mut new_bindings = HashMap::new();
new_bindings.insert(name, value.clone());
Ok(target.subst(&new_bindings))
}));
intrinsics.insert(6, wrap_binop(|a, b| a.checked_rem(b).context("division by zero")));
let intrinsics = Arc::new(intrinsics);
Env {
ruleset: vec![],
ops: ops.clone(),
intrinsics: intrinsics.clone(),
bindings: HashMap::new()
}
}
pub const BUILTINS: &str = "
SetStage[all]
a#Num + b#Num = Intrinsic[0]
a#Num - b#Num = Intrinsic[1]
a#Num * b#Num = Intrinsic[2]
a#Num / b#Num = Intrinsic[3]
a#Num ^ b#Num = Intrinsic[4]
Subst[var=value, target] = Intrinsic[5]
Mod[a#Num, b#Num] = Intrinsic[6]
PushRuleset[builtins]
";
pub const GENERAL_RULES: &str = "
SetStage[all]
(a*b#Num)+(a*c#Num) = (b+c)*a
Negate[a] = 0 - a
a^b*a^c = a^(b+c)
a^0 = 1
a^1 = a
(a^b)^c = a^(b*c)
0*a = 0
0+a = a
1*a = a
x/x = 1
(n*x)/x = n
PushRuleset[general_rules]
";
pub const NORMALIZATION_RULES: &str = "
SetStage[norm]
a/b = a*b^Negate[1]
a+b#Num*a = (b+1)*a
a^b#Num#Gte[b, 2] = a*a^(b-1)
a-c#Num*b = a+Negate[c]*b
a+a = 2*a
a*(b+c) = a*b+a*c
a-b = a+Negate[1]*b
PushRuleset[normalization]
";
pub const DENORMALIZATION_RULES: &str = "
SetStage[denorm]
a*a = a^2
a^b#Num*a = a^(b+1)
c+a*b#Num#Gte[0, b] = c-a*Negate[b]
PushRuleset[denormalization]
";
pub const DIFFERENTIATION_DEFINITION: &str = "
SetStage[all]
D[x, x] = 1
D[a#Num, x] = 0
D[f+g, x] = D[f, x] + D[g, x]
D[f*g, x] = D[f, x] * g + D[g, x] * f
D[a#Num*f, x] = a * D[f, x]
PushRuleset[differentiation]
";
pub const FACTOR_DEFINITION: &str = "
SetStage[post_norm]
Factor[x, a*x+b] = x * (a + Factor[x, b] / x)
PushRuleset[factor]
SetStage[pre_denorm]
Factor[x, a] = a
PushRuleset[factor_postprocess]
SetStage[denorm]
x^n/x = x^(n-1)
(a*x^n)/x = a*x^(n-1)
PushRuleset[factor_postpostprocess]
";
pub struct ImperativeCtx {
bindings: Bindings,
current_ruleset_stage: InlinableString,
current_ruleset: Ruleset,
rulesets: HashMap<InlinableString, Arc<Ruleset>>,
stages: Vec<(InlinableString, Vec<InlinableString>)>,
pub base_env: Env
}
impl ImperativeCtx {
// Make a new imperative context
// Stages are currently hardcoded, as adding a way to manage them would add lots of complexity
// for limited benefit
pub fn init() -> Self {
let stages = [
"pre_norm",
"norm",
"post_norm",
"pre_denorm",
"denorm",
"post_denorm"
].iter().map(|name| (InlinableString::from(*name), vec![])).collect();
ImperativeCtx {
bindings: HashMap::new(),
current_ruleset_stage: InlinableString::from("post_norm"),
current_ruleset: HashMap::new(),
rulesets: HashMap::new(),
stages,
base_env: make_initial_env()
}
}
// Insert a rule into the current ruleset; handles switching out the result for a relevant intrinsic use, generating possible reorderings, and inserting into the lookup map.
fn insert_rule(&mut self, condition: &Value, result_val: Value) -> Result<()> {
let result = match result_val {
Value::Call(head, args) if head == "Intrinsic" => RuleResult::Intrinsic(args[0].assert_num("Intrinsic ID")? as usize),
_ => RuleResult::Exp(result_val)
};
for rearrangement in condition.pattern_reorderings(&self.base_env).into_iter() {
let rule = Rule {
condition: rearrangement,
result: result.clone()
};
self.current_ruleset.entry(condition.head().unwrap()).or_insert_with(Vec::new).push(rule);
}
Ok(())
}
// Run a single statement (roughly, a line of user input) on the current context
fn eval_statement(&mut self, mut stmt: Value) -> Result<Option<Value>> {
match stmt {
// = sets a binding or generates a new rule.
Value::Call(head, args) if head.as_ref() == "=" => {
match &args[0] {
// Create a binding if the LHS (left hand side) is just an identifier
Value::Identifier(id) => {
let rhs = self.eval_statement(args[1].clone())?;
if let Some(val) = rhs.clone() {
self.bindings.insert(id.clone(), val);
}
Ok(rhs)
},
// If the LHS is a call, then a rule should be created instead.
Value::Call(_head, _args) => {
let rhs = self.eval_statement(args[1].clone())?;
if let Some(val) = rhs.clone() {
self.insert_rule(&args[0], val)?;
}
Ok(rhs)
},
// Rebinding numbers can only bring confusion, so it is not allowed.
// They also do not have a head, and so cannot be inserted into the ruleset anyway.
Value::Num(_) => bail!("You cannot rebind numbers")
}
},
// SetStage[] calls set the stage the current ruleset will be applied at
Value::Call(head, args) if head.as_ref() == "SetStage" => {
let stage = args[0].assert_ident("SetStage requires an identifier for stage")?;
if stage != "all" && None == self.stages.iter().position(|s| s.0 == stage) {
bail!("No such stage {}", stage);
}
self.current_ruleset_stage = stage;
Ok(None)
},
// Move the current ruleset from the "buffer" into the actual list of rules to be applied at each stage
Value::Call(head, args) if head.as_ref() == "PushRuleset" => {
let name = args[0].assert_ident("PushRuleset requires an identifier for ruleset name")?;
// Get ruleset and set the current one to empty
let ruleset = std::mem::replace(&mut self.current_ruleset, HashMap::new());
// Push ruleset to stages it specifies
for (stage_name, stage_rulesets) in self.stages.iter_mut() {
if *stage_name == self.current_ruleset_stage || self.current_ruleset_stage == "all" {
stage_rulesets.push(name.clone());
}
}
// Insert actual ruleset data under its name
self.rulesets.insert(name, Arc::new(ruleset));
Ok(None)
},
// Anything not special should just be repeatedly run through each rewrite stage.
_ => {
let env = self.base_env.with_bindings(&self.bindings);
for (stage_name, stage_rulesets) in self.stages.iter() {
// Add relevant rulesets to a new environment for this stage
let mut env = env.clone();
for ruleset in stage_rulesets.iter() {
env = env.with_ruleset(self.rulesets[ruleset].clone());
}
// Also add the current ruleset if applicable
if self.current_ruleset_stage == *stage_name || self.current_ruleset_stage == "all" {
env = env.with_ruleset(Arc::new(self.current_ruleset.clone()));
}
run_rewrite(&mut stmt, &env).with_context(|| format!("failed in {} stage", stage_name))?;
// If a ruleset is only meant to be applied in one particular stage, it shouldn't have any later stages applied to it,
// or the transformation it's meant to do may be undone
if self.current_ruleset_stage == *stage_name {
break
}
}
Ok(Some(stmt))
}
}
}
// Evaluate an entire "program" (multiple statements delineated by ; or newlines)
pub fn eval_program(&mut self, program: &str) -> Result<Option<Value>> {
let mut tokens = parse::lex(program)?;
let mut last_value = None;
loop {
// Split at the next break token
let remaining_tokens = tokens.iter().position(|x| *x == parse::Token::Break).map(|ix| tokens.split_off(ix + 1));
// Trim EOF/break tokens
match tokens[tokens.len() - 1] {
parse::Token::Break | parse::Token::EOF => tokens.truncate(tokens.len() - 1),
_ => ()
};
// If the statement/line isn't blank, readd EOF for the parser, parse into an AST then Value, and evaluate the statement
if tokens.len() > 0 {
tokens.push(parse::Token::EOF);
let value = Value::from_ast(parse::parse(tokens)?);
last_value = self.eval_statement(value)?;
}
// If there was no break after the current position, this is now done. Otherwise, move onto the new remaining tokens.
match remaining_tokens {
Some(t) => { tokens = t },
None => break
}
}
Ok(last_value)
}
}
static mut JS_CONTEXT: Option<ImperativeCtx> = None;
#[wasm_bindgen]
pub fn init_context() {
unsafe {
JS_CONTEXT = Some(ImperativeCtx::init());
}
}
unsafe fn load_defaults_internal() -> Result<()> {
let ctx = (&mut JS_CONTEXT).as_mut().unwrap();
ctx.eval_program(BUILTINS)?;
ctx.eval_program(GENERAL_RULES)?;
ctx.eval_program(FACTOR_DEFINITION)?;
ctx.eval_program(DENORMALIZATION_RULES)?;
ctx.eval_program(NORMALIZATION_RULES)?;
ctx.eval_program(DIFFERENTIATION_DEFINITION)?;
Ok(())
}
#[wasm_bindgen]
pub fn load_defaults() {
unsafe {
load_defaults_internal().unwrap();
}
}
#[wasm_bindgen]
pub fn run_program(program: &str) -> String {
unsafe {
let ctx = (&mut JS_CONTEXT).as_mut().unwrap();
match ctx.eval_program(program) {
Ok(Some(result)) => result.render_to_string(&ctx.base_env).to_string(),
Ok(None) => String::new(),
Err(e) => format!("Error: {:?}", e)
}
}
}
#[wasm_bindgen]
pub fn deinit_context() {
unsafe {
std::mem::take(&mut JS_CONTEXT);
}
}
#[cfg(test)]
mod test {
use crate::{ImperativeCtx, BUILTINS, GENERAL_RULES, NORMALIZATION_RULES, DENORMALIZATION_RULES, DIFFERENTIATION_DEFINITION, FACTOR_DEFINITION};
#[test]
fn end_to_end_tests() {
let mut ctx = ImperativeCtx::init();
ctx.eval_program(BUILTINS).unwrap();
ctx.eval_program(GENERAL_RULES).unwrap();
ctx.eval_program(FACTOR_DEFINITION).unwrap();
ctx.eval_program(DENORMALIZATION_RULES).unwrap();
ctx.eval_program(NORMALIZATION_RULES).unwrap();
ctx.eval_program(DIFFERENTIATION_DEFINITION).unwrap();
let test_cases = [
("Factor[x, x*3+x^2]", "(3+x)*x"),
("x^a/x^(a+1)", "x^Negate[1]"),
("Negate[a+b]", "Negate[1]*b-a"),
("Subst[x=4, x+4+4+4+4]", "20"),
("(a+b)*(c+d)*(e+f)", "a*c*e+a*c*f+a*d*e+a*d*f+b*c*e+b*c*f+b*d*e+b*d*f"),
("(12+55)^3-75+16/(2*2)+5+3*4", "300709"),
("D[3*x^3 + 6*x, x] ", "6+9*x^2"),
("Fib[n] = Fib[n-1] + Fib[n-2]
Fib[0] = 0
Fib[1] = 1
Fib[6]", "8"),
("Subst[b=a, b+a]", "2*a"),
("a = 7
b = Negate[4]
a + b", "3"),
("IsEven[x] = 0
IsEven[x#Eq[Mod[x, 2], 0]] = 1
IsEven[3] - IsEven[4]", "Negate[1]"),
("(a+b+c)^2", "2*a*b+2*a*c+2*b*c+a^2+b^2+c^2"),
("(x+2)^7", "128+2*x^6+12*x^5+12*x^6+16*x^3+16*x^5+24*x^4+24*x^5+32*x^2+32*x^3+32*x^5+128*x^2+256*x^4+448*x+512*x^2+512*x^3+x^7")
];
for (input, expected_result) in test_cases {
let lhs = ctx.eval_program(input).unwrap();
let lhs = lhs.as_ref().unwrap().render_to_string(&ctx.base_env);
println!("{} evaluated to {}; expected {}", input, lhs, expected_result);
assert_eq!(lhs, expected_result);
}
let error_cases = [
("1/0")
];
for error_case in error_cases {
if let Err(e) = ctx.eval_program(error_case) {
println!("{} produced error {:?}", error_case, e);
} else {
panic!("should have errored: {}", error_case)
}
}
println!("All tests passed.")
}
}

View File

@ -1,558 +1,6 @@
use anyhow::{Result, Context, bail}; use osmarkscalculator::*;
use inlinable_string::InlinableString;
use std::collections::HashMap;
use std::io::BufRead; use std::io::BufRead;
use std::borrow::Cow; use anyhow::Result;
use std::convert::TryInto;
use std::sync::Arc;
use rayon::prelude::*;
mod parse;
mod value;
mod util;
mod env;
use value::Value;
use env::{Rule, Ruleset, Env, Bindings, RuleResult, Operation};
// Main pattern matcher function;
fn match_and_bind(expr: &Value, rule: &Rule, env: &Env) -> Result<Option<Value>> {
fn go(expr: &Value, cond: &Value, env: &Env, already_bound: &Bindings) -> Result<Option<Bindings>> {
match (expr, cond) {
// numbers match themselves
(Value::Num(a), Value::Num(b)) => if a == b { Ok(Some(HashMap::new())) } else { Ok(None) },
// handle predicated value - check all predicates, succeed with binding if they match
(val, Value::Call(x, args)) if x == "#" => {
let preds = &args[1..];
let (mut success, mut bindings) = match go(val, &args[0], env, already_bound)? {
Some(bindings) => (true, bindings),
None => (false, already_bound.clone())
};
for pred in preds {
match pred {
// "Num" predicate matches successfully if something is a number
Value::Identifier(i) if i.as_ref() == "Num" => {
match val {
Value::Num(_) => (),
_ => success = false
}
},
// "Ident" does the same for idents
Value::Identifier(i) if i.as_ref() == "Ident" => {
match val {
Value::Identifier(_) => (),
_ => success = false
}
},
// Invert match success
Value::Identifier(i) if i.as_ref() == "Not" => {
success = !success
},
Value::Call(head, args) if head.as_ref() == "And" => {
// Try all patterns it's given, and if any fails then fail the match
for arg in args.iter() {
match go(val, arg, env, &bindings)? {
Some(new_bindings) => bindings.extend(new_bindings),
None => success = false
}
}
},
Value::Call(head, args) if head.as_ref() == "Eq" => {
// Evaluate all arguments and check if they are equal
let mut compare_against = None;
for arg in args.iter() {
let mut evaluated_value = arg.subst(&bindings);
run_rewrite(&mut evaluated_value, env).context("evaluating Eq predicate")?;
match compare_against {
Some(ref x) => if x != &evaluated_value {
success = false
},
None => compare_against = Some(evaluated_value)
}
}
},
Value::Call(head, args) if head.as_ref() == "Gte" => {
// Evaluate all arguments and do comparison.
let mut x = args[0].subst(&bindings);
let mut y = args[1].subst(&bindings);
run_rewrite(&mut x, env).context("evaluating Gte predicate")?;
run_rewrite(&mut y, env).context("evaluating Gte predicate")?;
success &= x >= y;
},
Value::Call(head, args) if head.as_ref() == "Or" => {
// Tries all patterns it's given and will set the match to successful if *any* of them works
for arg in args.iter() {
match go(val, arg, env, &bindings)? {
Some(new_bindings) => {
bindings.extend(new_bindings);
success = true
},
None => ()
}
}
},
_ => bail!("invalid predicate {:?}", pred)
}
}
Ok(match success {
true => Some(bindings),
false => None
})
},
(Value::Call(exp_head, exp_args), Value::Call(rule_head, rule_args)) => {
let mut exp_args = Cow::Borrowed(exp_args);
// Regardless of any special casing for associativity etc., different heads mean rules can never match
if exp_head != rule_head { return Ok(None) }
let op = env.get_op(exp_head);
// Copy bindings from the upper-level matching, so that things like "a+(b+a)" work.
let mut out_bindings = already_bound.clone();
// Special case for associative expressions: split off extra arguments into a new tree
if op.associative && rule_args.len() < exp_args.len() {
let exp_args = exp_args.to_mut();
let rest = exp_args.split_off(rule_args.len() - 1);
let rem = Value::Call(exp_head.clone(), rest);
exp_args.push(rem);
}
if rule_args.len() != exp_args.len() { return Ok(None) }
// Try and match all "adjacent" arguments to each other
for (rule_arg, exp_arg) in rule_args.iter().zip(&*exp_args) {
match go(exp_arg, rule_arg, env, &out_bindings)? {
Some(x) => out_bindings.extend(x),
None => return Ok(None)
}
}
Ok(Some(out_bindings))
},
// identifier pattern matches anything, unless the identifier has already been bound to something else
(x, Value::Identifier(a)) => {
if let Some(b) = already_bound.get(a) {
if b != x {
return Ok(None);
}
};
Ok(Some(vec![(a.clone(), x.clone())].into_iter().collect()))
},
// anything else doesn't match
_ => Ok(None)
}
}
// special case at top level of expression - try to match pattern to different subranges of input
match (expr, &rule.condition) {
// this only applies to matching one "call" against a "call" pattern (with same head)
(Value::Call(ehead, eargs), Value::Call(rhead, rargs)) => {
// and also only to associative operations
if env.get_op(ehead).associative && eargs.len() > rargs.len() && ehead == rhead {
// consider all possible subranges of the arguments of the appropriate length
for range_start in 0..=(eargs.len() - rargs.len()) {
// extract the arguments & convert into new Value
let c_args = eargs[range_start..range_start + rargs.len()].iter().cloned().collect();
let c_call = Value::Call(ehead.clone(), c_args);
// attempt to match the new subrange against the current rule
if let Some(r) = match_and_bind(&c_call, rule, env)? {
// generate new output with result
let mut new_args = Vec::with_capacity(3);
// add back extra start items
if range_start != 0 {
new_args.push(Value::Call(ehead.clone(), eargs[0..range_start].iter().cloned().collect()))
}
new_args.push(r);
// add back extra end items
if range_start + rargs.len() != eargs.len() {
new_args.push(Value::Call(ehead.clone(), eargs[range_start + rargs.len()..eargs.len()].iter().cloned().collect()))
}
let new_exp = Value::Call(ehead.clone(), new_args);
return Ok(Some(new_exp))
}
}
}
}
_ => ()
}
// substitute bindings from matching into either an intrinsic or the output of the rule
if let Some(bindings) = go(expr, &rule.condition, env, &HashMap::new())? {
Ok(Some(match &rule.result {
RuleResult::Intrinsic(id) => env.intrinsics.get(id).unwrap()(&bindings).with_context(|| format!("applying intrinsic {}", id))?,
RuleResult::Exp(e) => e.subst(&bindings)
}))
} else {
Ok(None)
}
}
// Sort any commutative expressions
fn canonical_sort(v: &mut Value, env: &Env) -> Result<()> {
match v {
Value::Call(head, args) => if env.get_op(head).commutative {
args.sort();
},
_ => ()
}
Ok(())
}
// Associative expression flattening.
fn flatten_tree(v: &mut Value, env: &Env) -> Result<()> {
match v {
Value::Call(head, args) => {
if env.get_op(head).associative {
// Not the most efficient algorithm, but does work.
// Repeatedly find the position of a flatten-able child node, and splice it into the argument list.
loop {
let mut move_pos = None;
for (i, child) in args.iter().enumerate() {
if let Some(child_head) = child.head() {
if *head == child_head {
move_pos = Some(i)
}
}
}
match move_pos {
Some(pos) => {
let removed = std::mem::replace(&mut args[pos], Value::Num(0));
// We know that removed will be a Call (because its head wasn't None earlier). Unfortunately, rustc does not know this.
match removed {
Value::Call(_, removed_child_args) => args.splice(pos..=pos, removed_child_args.into_iter()),
_ => unreachable!()
};
},
None => break
}
}
}
// Also do sorting after flattening, to avoid any weirdness with ordering.
canonical_sort(v, env)?;
return Ok(())
},
_ => return Ok(())
}
}
// Applies rewrite rulesets to an expression.
fn run_rewrite(v: &mut Value, env: &Env) -> Result<()> {
loop {
// Compare original and final hash instead of storing a copy of the original value and checking equality
// Collision probability is negligible and this is substantially faster than storing/comparing copies.
let original_hash = v.get_hash();
flatten_tree(v, env).context("flattening tree")?;
// Call expressions can be rewritten using pattern matching rules; identifiers can be substituted for bindings if available
match v {
Value::Call(head, args) => {
let head = head.clone();
// Rewrite sub-expressions using existing environment
args.par_iter_mut().try_for_each(|arg| run_rewrite(arg, env).with_context(|| format!("rewriting {}", arg.render_to_string(env))))?;
// Try to apply all applicable rules from all rulesets, in sequence
for ruleset in env.ruleset.iter() {
if let Some(rules) = ruleset.get(&head) {
// Within a ruleset, rules are applied backward. This is nicer for users using the program interactively.
for rule in rules.iter().rev() {
if let Some(result) = match_and_bind(v, rule, env).with_context(|| format!("applying rule {} -> {:?}", rule.condition.render_to_string(env), rule.result))? {
*v = result;
flatten_tree(v, env).context("flattening tree after rule application")?;
}
}
}
}
},
// Substitute in bindings which have been provided
Value::Identifier(ident) => {
match env.bindings.get(ident) {
Some(val) => {
*v = val.clone();
},
None => return Ok(())
}
},
_ => {
return Ok(())
}
}
if original_hash == v.get_hash() {
break
}
}
Ok(())
}
// Utility function for defining intrinsic functions for binary operators.
// Converts a function which does the actual operation to a function from bindings to a value.
fn wrap_binop<F: 'static + Fn(i128, i128) -> Result<i128> + Sync + Send>(op: F) -> Box<dyn Fn(&Bindings) -> Result<Value> + Sync + Send> {
Box::new(move |bindings: &Bindings| {
let a = bindings.get(&InlinableString::from("a")).context("binop missing first argument")?.assert_num("binop first argument")?;
let b = bindings.get(&InlinableString::from("b")).context("binop missing second argument")?.assert_num("binop second argument")?;
op(a, b).map(Value::Num)
})
}
// Provides a basic environment with operator commutativity/associativity operations and intrinsics.
fn make_initial_env() -> Env {
let mut ops = HashMap::new();
ops.insert(InlinableString::from("+"), Operation { commutative: true, associative: true });
ops.insert(InlinableString::from("*"), Operation { commutative: true, associative: true });
ops.insert(InlinableString::from("-"), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("/"), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("^"), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("="), Operation { commutative: false, associative: false });
ops.insert(InlinableString::from("#"), Operation { commutative: false, associative: true });
let ops = Arc::new(ops);
let mut intrinsics = HashMap::new();
intrinsics.insert(0, wrap_binop(|a, b| a.checked_add(b).context("integer overflow")));
intrinsics.insert(1, wrap_binop(|a, b| a.checked_sub(b).context("integer overflow")));
intrinsics.insert(2, wrap_binop(|a, b| a.checked_mul(b).context("integer overflow")));
intrinsics.insert(3, wrap_binop(|a, b| a.checked_div(b).context("division by zero")));
intrinsics.insert(4, wrap_binop(|a, b| {
// The "pow" function takes a usize (machine-sized unsigned integer) and an i128 may not fit into this, so an extra conversion is needed
Ok(a.pow(b.try_into()?))
}));
intrinsics.insert(5, Box::new(|bindings| {
// Substitute a single, given binding var=value into a target expression
let var = bindings.get(&InlinableString::from("var")).unwrap();
let value = bindings.get(&InlinableString::from("value")).unwrap();
let target = bindings.get(&InlinableString::from("target")).unwrap();
let name = var.assert_ident("Subst")?;
let mut new_bindings = HashMap::new();
new_bindings.insert(name, value.clone());
Ok(target.subst(&new_bindings))
}));
intrinsics.insert(6, wrap_binop(|a, b| a.checked_rem(b).context("division by zero")));
let intrinsics = Arc::new(intrinsics);
Env {
ruleset: vec![],
ops: ops.clone(),
intrinsics: intrinsics.clone(),
bindings: HashMap::new()
}
}
const BUILTINS: &str = "
SetStage[all]
a#Num + b#Num = Intrinsic[0]
a#Num - b#Num = Intrinsic[1]
a#Num * b#Num = Intrinsic[2]
a#Num / b#Num = Intrinsic[3]
a#Num ^ b#Num = Intrinsic[4]
Subst[var=value, target] = Intrinsic[5]
Mod[a#Num, b#Num] = Intrinsic[6]
PushRuleset[builtins]
";
const GENERAL_RULES: &str = "
SetStage[all]
(a*b#Num)+(a*c#Num) = (b+c)*a
Negate[a] = 0 - a
a^b*a^c = a^(b+c)
a^0 = 1
a^1 = a
(a^b)^c = a^(b*c)
0*a = 0
0+a = a
1*a = a
x/x = 1
(n*x)/x = n
PushRuleset[general_rules]
";
const NORMALIZATION_RULES: &str = "
SetStage[norm]
a/b = a*b^Negate[1]
a+b#Num*a = (b+1)*a
a^b#Num#Gte[b, 2] = a*a^(b-1)
a-c#Num*b = a+Negate[c]*b
a+a = 2*a
a*(b+c) = a*b+a*c
a-b = a+Negate[1]*b
PushRuleset[normalization]
";
const DENORMALIZATION_RULES: &str = "
SetStage[denorm]
a*a = a^2
a^b#Num*a = a^(b+1)
c+a*b#Num#Gte[0, b] = c-a*Negate[b]
PushRuleset[denormalization]
";
const DIFFERENTIATION_DEFINITION: &str = "
SetStage[all]
D[x, x] = 1
D[a#Num, x] = 0
D[f+g, x] = D[f, x] + D[g, x]
D[f*g, x] = D[f, x] * g + D[g, x] * f
D[a#Num*f, x] = a * D[f, x]
PushRuleset[differentiation]
";
const FACTOR_DEFINITION: &str = "
SetStage[post_norm]
Factor[x, a*x+b] = x * (a + Factor[x, b] / x)
PushRuleset[factor]
SetStage[pre_denorm]
Factor[x, a] = a
PushRuleset[factor_postprocess]
SetStage[denorm]
x^n/x = x^(n-1)
(a*x^n)/x = a*x^(n-1)
PushRuleset[factor_postpostprocess]
";
struct ImperativeCtx {
bindings: Bindings,
current_ruleset_stage: InlinableString,
current_ruleset: Ruleset,
rulesets: HashMap<InlinableString, Arc<Ruleset>>,
stages: Vec<(InlinableString, Vec<InlinableString>)>,
base_env: Env
}
impl ImperativeCtx {
// Make a new imperative context
// Stages are currently hardcoded, as adding a way to manage them would add lots of complexity
// for limited benefit
fn init() -> Self {
let stages = [
"pre_norm",
"norm",
"post_norm",
"pre_denorm",
"denorm",
"post_denorm"
].iter().map(|name| (InlinableString::from(*name), vec![])).collect();
ImperativeCtx {
bindings: HashMap::new(),
current_ruleset_stage: InlinableString::from("post_norm"),
current_ruleset: HashMap::new(),
rulesets: HashMap::new(),
stages,
base_env: make_initial_env()
}
}
// Insert a rule into the current ruleset; handles switching out the result for a relevant intrinsic use, generating possible reorderings, and inserting into the lookup map.
fn insert_rule(&mut self, condition: &Value, result_val: Value) -> Result<()> {
let result = match result_val {
Value::Call(head, args) if head == "Intrinsic" => RuleResult::Intrinsic(args[0].assert_num("Intrinsic ID")? as usize),
_ => RuleResult::Exp(result_val)
};
for rearrangement in condition.pattern_reorderings(&self.base_env).into_iter() {
let rule = Rule {
condition: rearrangement,
result: result.clone()
};
self.current_ruleset.entry(condition.head().unwrap()).or_insert_with(Vec::new).push(rule);
}
Ok(())
}
// Run a single statement (roughly, a line of user input) on the current context
fn eval_statement(&mut self, mut stmt: Value) -> Result<Option<Value>> {
match stmt {
// = sets a binding or generates a new rule.
Value::Call(head, args) if head.as_ref() == "=" => {
match &args[0] {
// Create a binding if the LHS (left hand side) is just an identifier
Value::Identifier(id) => {
let rhs = self.eval_statement(args[1].clone())?;
if let Some(val) = rhs.clone() {
self.bindings.insert(id.clone(), val);
}
Ok(rhs)
},
// If the LHS is a call, then a rule should be created instead.
Value::Call(_head, _args) => {
let rhs = self.eval_statement(args[1].clone())?;
if let Some(val) = rhs.clone() {
self.insert_rule(&args[0], val)?;
}
Ok(rhs)
},
// Rebinding numbers can only bring confusion, so it is not allowed.
// They also do not have a head, and so cannot be inserted into the ruleset anyway.
Value::Num(_) => bail!("You cannot rebind numbers")
}
},
// SetStage[] calls set the stage the current ruleset will be applied at
Value::Call(head, args) if head.as_ref() == "SetStage" => {
let stage = args[0].assert_ident("SetStage requires an identifier for stage")?;
if stage != "all" && None == self.stages.iter().position(|s| s.0 == stage) {
bail!("No such stage {}", stage);
}
self.current_ruleset_stage = stage;
Ok(None)
},
// Move the current ruleset from the "buffer" into the actual list of rules to be applied at each stage
Value::Call(head, args) if head.as_ref() == "PushRuleset" => {
let name = args[0].assert_ident("PushRuleset requires an identifier for ruleset name")?;
// Get ruleset and set the current one to empty
let ruleset = std::mem::replace(&mut self.current_ruleset, HashMap::new());
// Push ruleset to stages it specifies
for (stage_name, stage_rulesets) in self.stages.iter_mut() {
if *stage_name == self.current_ruleset_stage || self.current_ruleset_stage == "all" {
stage_rulesets.push(name.clone());
}
}
// Insert actual ruleset data under its name
self.rulesets.insert(name, Arc::new(ruleset));
Ok(None)
},
// Anything not special should just be repeatedly run through each rewrite stage.
_ => {
let env = self.base_env.with_bindings(&self.bindings);
for (stage_name, stage_rulesets) in self.stages.iter() {
// Add relevant rulesets to a new environment for this stage
let mut env = env.clone();
for ruleset in stage_rulesets.iter() {
env = env.with_ruleset(self.rulesets[ruleset].clone());
}
// Also add the current ruleset if applicable
if self.current_ruleset_stage == *stage_name || self.current_ruleset_stage == "all" {
env = env.with_ruleset(Arc::new(self.current_ruleset.clone()));
}
run_rewrite(&mut stmt, &env).with_context(|| format!("failed in {} stage", stage_name))?;
// If a ruleset is only meant to be applied in one particular stage, it shouldn't have any later stages applied to it,
// or the transformation it's meant to do may be undone
if self.current_ruleset_stage == *stage_name {
break
}
}
Ok(Some(stmt))
}
}
}
// Evaluate an entire "program" (multiple statements delineated by ; or newlines)
fn eval_program(&mut self, program: &str) -> Result<Option<Value>> {
let mut tokens = parse::lex(program)?;
let mut last_value = None;
loop {
// Split at the next break token
let remaining_tokens = tokens.iter().position(|x| *x == parse::Token::Break).map(|ix| tokens.split_off(ix + 1));
// Trim EOF/break tokens
match tokens[tokens.len() - 1] {
parse::Token::Break | parse::Token::EOF => tokens.truncate(tokens.len() - 1),
_ => ()
};
// If the statement/line isn't blank, readd EOF for the parser, parse into an AST then Value, and evaluate the statement
if tokens.len() > 0 {
tokens.push(parse::Token::EOF);
let value = Value::from_ast(parse::parse(tokens)?);
last_value = self.eval_statement(value)?;
}
// If there was no break after the current position, this is now done. Otherwise, move onto the new remaining tokens.
match remaining_tokens {
Some(t) => { tokens = t },
None => break
}
}
Ok(last_value)
}
}
fn main() -> Result<()> { fn main() -> Result<()> {
let mut ctx = ImperativeCtx::init(); let mut ctx = ImperativeCtx::init();
@ -572,62 +20,4 @@ fn main() -> Result<()> {
} }
} }
Ok(()) Ok(())
}
#[cfg(test)]
mod test {
use crate::{ImperativeCtx, BUILTINS, GENERAL_RULES, NORMALIZATION_RULES, DENORMALIZATION_RULES, DIFFERENTIATION_DEFINITION, FACTOR_DEFINITION};
#[test]
fn end_to_end_tests() {
let mut ctx = ImperativeCtx::init();
ctx.eval_program(BUILTINS).unwrap();
ctx.eval_program(GENERAL_RULES).unwrap();
ctx.eval_program(FACTOR_DEFINITION).unwrap();
ctx.eval_program(DENORMALIZATION_RULES).unwrap();
ctx.eval_program(NORMALIZATION_RULES).unwrap();
ctx.eval_program(DIFFERENTIATION_DEFINITION).unwrap();
let test_cases = [
("Factor[x, x*3+x^2]", "(3+x)*x"),
("x^a/x^(a+1)", "x^Negate[1]"),
("Negate[a+b]", "Negate[1]*b-a"),
("Subst[x=4, x+4+4+4+4]", "20"),
("(a+b)*(c+d)*(e+f)", "a*c*e+a*c*f+a*d*e+a*d*f+b*c*e+b*c*f+b*d*e+b*d*f"),
("(12+55)^3-75+16/(2*2)+5+3*4", "300709"),
("D[3*x^3 + 6*x, x] ", "6+9*x^2"),
("Fib[n] = Fib[n-1] + Fib[n-2]
Fib[0] = 0
Fib[1] = 1
Fib[6]", "8"),
("Subst[b=a, b+a]", "2*a"),
("a = 7
b = Negate[4]
a + b", "3"),
("IsEven[x] = 0
IsEven[x#Eq[Mod[x, 2], 0]] = 1
IsEven[3] - IsEven[4]", "Negate[1]"),
("(a+b+c)^2", "2*a*b+2*a*c+2*b*c+a^2+b^2+c^2"),
("(x+2)^7", "128+2*x^6+12*x^5+12*x^6+16*x^3+16*x^5+24*x^4+24*x^5+32*x^2+32*x^3+32*x^5+128*x^2+256*x^4+448*x+512*x^2+512*x^3+x^7")
];
for (input, expected_result) in test_cases {
let lhs = ctx.eval_program(input).unwrap();
let lhs = lhs.as_ref().unwrap().render_to_string(&ctx.base_env);
println!("{} evaluated to {}; expected {}", input, lhs, expected_result);
assert_eq!(lhs, expected_result);
}
let error_cases = [
("1/0")
];
for error_case in error_cases {
if let Err(e) = ctx.eval_program(error_case) {
println!("{} produced error {:?}", error_case, e);
} else {
panic!("should have errored: {}", error_case)
}
}
println!("All tests passed.")
}
} }