From c47132c3892a5099fb892a14d19494f52acc40b6 Mon Sep 17 00:00:00 2001
From: mehbark <terezi@pyrope.net>
Date: Mon, 10 Mar 2025 22:16:48 -0400
Subject: [PATCH] use lua

---
 Cargo.lock  | 256 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |   1 +
 src/main.rs | 179 +++++++-----------------------------
 3 files changed, 291 insertions(+), 145 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a5d0608..c30458e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -52,6 +52,43 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "autocfg"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
+
+[[package]]
+name = "bitflags"
+version = "2.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c8214115b7bf84099f1309324e63141d4c5d7cc26862f97a0a857dbefe165bd"
+
+[[package]]
+name = "bstr"
+version = "1.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "531a9155a481e2ee699d4f98f43c0ca4ff8ee1bfd55c31e9e98fb29d2b176fe0"
+dependencies = [
+ "memchr",
+ "serde",
+]
+
+[[package]]
+name = "cc"
+version = "1.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be714c154be609ec7f5dad223a33bf1482fff90472de28f7362806e6d4832b8c"
+dependencies = [
+ "shlex",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
 [[package]]
 name = "clap"
 version = "4.5.32"
@@ -98,11 +135,34 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
 
+[[package]]
+name = "either"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
+
+[[package]]
+name = "env_home"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7f84e12ccf0a7ddc17a6c41c93326024c42920d7ee630d04950e6926645c0fe"
+
+[[package]]
+name = "errno"
+version = "0.3.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33d852cb9b869c2a9b3df2f71a3074817f01e1844f839a144f5fcef059a4eb5d"
+dependencies = [
+ "libc",
+ "windows-sys",
+]
+
 [[package]]
 name = "grapher"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "mlua",
 ]
 
 [[package]]
@@ -117,12 +177,124 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "libc"
+version = "0.2.170"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "875b3680cb2f8f71bdcf9a30f38d48282f5d3c95cbf9b3fa57269bb5d5c06828"
+
+[[package]]
+name = "linux-raw-sys"
+version = "0.4.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d26c52dbd32dccf2d10cac7725f8eae5296885fb5703b261f7d0a0739ec807ab"
+
+[[package]]
+name = "lock_api"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07af8b9cdd281b7915f413fa73f29ebd5d55d0d3f0155584dade1ff18cea1b17"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
+[[package]]
+name = "lua-src"
+version = "547.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1edaf29e3517b49b8b746701e5648ccb5785cde1c119062cbabbc5d5cd115e42"
+dependencies = [
+ "cc",
+]
+
+[[package]]
+name = "luajit-src"
+version = "210.5.12+a4f56a4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3a8e7962a5368d5f264d045a5a255e90f9aa3fc1941ae15a8d2940d42cac671"
+dependencies = [
+ "cc",
+ "which",
+]
+
+[[package]]
+name = "memchr"
+version = "2.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
+
+[[package]]
+name = "mlua"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3f763c1041eff92ffb5d7169968a327e1ed2ebfe425dac0ee5a35f29082534b"
+dependencies = [
+ "bstr",
+ "either",
+ "mlua-sys",
+ "num-traits",
+ "parking_lot",
+ "rustc-hash",
+]
+
+[[package]]
+name = "mlua-sys"
+version = "0.6.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1901c1a635a22fe9250ffcc4fcc937c16b47c2e9e71adba8784af8bca1f69594"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "lua-src",
+ "luajit-src",
+ "pkg-config",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cde51589ab56b20a6f686b2c68f7a0bd6add753d697abf720d63f8db3ab7b1ad"
 
+[[package]]
+name = "parking_lot"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1bf18183cf54e8d6059647fc3063646a1801cf30896933ec2311622cc4b9a27"
+dependencies = [
+ "lock_api",
+ "parking_lot_core",
+]
+
+[[package]]
+name = "parking_lot_core"
+version = "0.9.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e401f977ab385c9e4e3ab30627d6f26d00e2c73eef317493c4ec6d468726cf8"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall",
+ "smallvec",
+ "windows-targets",
+]
+
+[[package]]
+name = "pkg-config"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.94"
@@ -141,6 +313,72 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "redox_syscall"
+version = "0.5.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b8c0c260b63a8219631167be35e6a988e9554dbd323f8bd08439c8ed1302bd1"
+dependencies = [
+ "bitflags",
+]
+
+[[package]]
+name = "rustc-hash"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"
+
+[[package]]
+name = "rustix"
+version = "0.38.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fdb5bc1ae2baa591800df16c9ca78619bf65c0488b41b96ccec5d11220d8c154"
+dependencies = [
+ "bitflags",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys",
+]
+
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
+[[package]]
+name = "serde"
+version = "1.0.219"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f0e2c6ed6606019b4e29e69dbaba95b11854410e5347d525002456dbbb786b6"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.219"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b0276cf7f2c73365f7157c8123c21cd9a50fbbd844757af28ca1f5925fc2a00"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
+[[package]]
+name = "smallvec"
+version = "1.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fcf8323ef1faaee30a44a340193b1ac6814fd9b7b4e88e9d4519a3e4abe1cfd"
+
 [[package]]
 name = "strsim"
 version = "0.11.1"
@@ -170,6 +408,18 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
+[[package]]
+name = "which"
+version = "7.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2774c861e1f072b3aadc02f8ba886c26ad6321567ecc294c935434cad06f1283"
+dependencies = [
+ "either",
+ "env_home",
+ "rustix",
+ "winsafe",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.59.0"
@@ -242,3 +492,9 @@ name = "windows_x86_64_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
+[[package]]
+name = "winsafe"
+version = "0.0.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d135d17ab770252ad95e9a872d365cf3090e3be864a34ab46f48555993efc904"
diff --git a/Cargo.toml b/Cargo.toml
index f0216fb..dc0f7ab 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,3 +5,4 @@ edition = "2021"
 
 [dependencies]
 clap = { version = "4.5.32", features = ["derive"] }
+mlua = { version = "0.10.3", features = ["lua54", "vendored"] }
diff --git a/src/main.rs b/src/main.rs
index 14af16a..9d78218 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,14 +1,7 @@
-use std::{
-    error::Error,
-    fmt::{self},
-    num::NonZero,
-    ops::{Add, Div, Mul, Sub},
-    process,
-    str::FromStr,
-};
+use std::{num::NonZero, process};
 
 use clap::Parser;
-
+use mlua::Lua;
 fn main() {
     let Args {
         width,
@@ -19,23 +12,40 @@ fn main() {
         xmax,
         ymax,
     } = Args::parse();
-    let expr = match expr.parse::<Expr>() {
-        Ok(expr) => expr,
-        Err(err) => {
-            eprintln!("{err}");
+    let lua = Lua::new();
+
+    // so we can write unqualified sin, cos, etc
+    lua.load("setmetatable(_G, {__index = math})")
+        .exec()
+        .unwrap();
+
+    match lua
+        .load(format!(
+            r"
+        function f(x, y)
+          return {expr}
+        end
+    "
+        ))
+        .exec()
+    {
+        Ok(()) => {}
+        Err(e) => {
+            eprintln!("lua load error: {e}");
             process::exit(1);
         }
     };
 
+    let f: mlua::Function = lua.globals().get("f").unwrap();
+    let f = |x: f32, y: f32| -> f32 { f.call((x, y)).expect("return f32 plz") };
+
     let pos_to_sample = |ix: u16, iy: u16| -> (f32, f32) {
         // TODO: bad
         let (width, height): (u16, u16) = (width.into(), height.into());
         let (width, height): (f32, f32) = (width.into(), height.into());
         let (x, y) = (f32::from(ix), f32::from(iy));
-        (
-            x / width * (xmax - xmin) + xmin,
-            y / height * (ymax - ymin) + ymin,
-        )
+        let (xt, yt) = (x / width, y / height);
+        (xt * (xmax - xmin) + xmin, yt * (ymax - ymin) + ymin)
     };
 
     let (mut min, mut max) = (-1.0f32, 1.0f32);
@@ -44,26 +54,28 @@ fn main() {
     for iy in 0..(height.into()) {
         for ix in 0..(width.into()) {
             let (x, y) = pos_to_sample(ix, iy);
-            let i = expr.eval(x, y);
+            let i = f(x, y);
             min = min.min(i);
             max = max.max(i);
         }
     }
     let (min, max) = (min, max);
 
-    for iy in 0..(height.into()) {
+    for iy in (0..(height.into())).rev() {
         for ix in 0..(width.into()) {
             let (x, y) = pos_to_sample(ix, iy);
-            let i = expr.eval(x, y);
+            let i = f(x, y);
             let scaled = i / (max - min);
-            let channel = (scaled * 256.0) as u8;
+            #[allow(clippy::cast_sign_loss, clippy::cast_possible_truncation)]
+            // cube rooting makes things sharper
+            let channel = (scaled.cbrt() * 256.) as u8;
             put_pixel(channel, channel, channel);
             put_pixel(channel, channel, channel);
         }
         println!();
     }
     // reset style
-    print!("\x1b[0m")
+    print!("\x1b[0m");
 }
 
 fn put_pixel(r: u8, g: u8, b: u8) {
@@ -87,126 +99,3 @@ struct Args {
     #[arg(default_value_t = 1.0)]
     ymax: f32,
 }
-
-#[derive(Debug)]
-enum Expr {
-    X,
-    Y,
-    Const(f32),
-    Monadic(fn(f32) -> f32, Box<Expr>),
-    Dyadic(fn(f32, f32) -> f32, Box<Expr>, Box<Expr>),
-}
-
-#[derive(Debug)]
-enum ExprFunction {
-    Monadic(fn(f32) -> f32),
-    Dyadic(fn(f32, f32) -> f32),
-}
-
-impl FromStr for ExprFunction {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        use ExprFunction::{Dyadic, Monadic};
-        let func = match s {
-            "sin" => Monadic(f32::sin),
-            "cos" => Monadic(f32::cos),
-            "tan" => Monadic(f32::tan),
-            "arcsin" | "asin" => Monadic(f32::asin),
-            "arccos" | "acos" => Monadic(f32::acos),
-            "arctan" | "atan" => Monadic(f32::atan),
-            "sqrt" => Monadic(f32::sqrt),
-            "abs" => Monadic(f32::abs),
-            "+" => Dyadic(Add::add),
-            "-" => Dyadic(Sub::sub),
-            "*" => Dyadic(Mul::mul),
-            "/" => Dyadic(Div::div),
-            "^" => Dyadic(f32::powf),
-            _ => return Err(()),
-        };
-        Ok(func)
-    }
-}
-
-impl Expr {
-    #[allow(clippy::many_single_char_names)]
-    fn eval(&self, x: f32, y: f32) -> f32 {
-        match self {
-            Expr::X => x,
-            Expr::Y => y,
-            Expr::Const(n) => *n,
-            Expr::Monadic(f, expr) => f(expr.eval(x, y)),
-            Expr::Dyadic(f, a, b) => f(a.eval(x, y), b.eval(x, y)),
-        }
-    }
-}
-
-#[derive(Debug)]
-enum ExprParseError {
-    UnknownToken { token: String, stack: Vec<Expr> },
-    ExpectedToken { stack: Vec<Expr> },
-}
-
-impl fmt::Display for ExprParseError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            ExprParseError::UnknownToken { token, stack } => write!(
-                f,
-                "Unknown token: \"{}\" Stack: {stack:?}",
-                token.escape_debug()
-            ),
-            ExprParseError::ExpectedToken { stack } => write!(f, "Expected token Stack: {stack:?}"),
-        }
-    }
-}
-
-impl Error for ExprParseError {}
-
-impl FromStr for Expr {
-    type Err = ExprParseError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        use Expr::{Const, Dyadic, Monadic, X, Y};
-        let mut stack = Vec::new();
-        for token in s.split_ascii_whitespace() {
-            if token == "x" {
-                stack.push(X);
-                continue;
-            }
-            if token == "y" {
-                stack.push(Y);
-                continue;
-            }
-
-            if let Ok(n) = token.parse() {
-                stack.push(Const(n));
-                continue;
-            }
-
-            match ExprFunction::from_str(token) {
-                Ok(ExprFunction::Monadic(f)) => {
-                    let Some(x) = stack.pop() else {
-                        return Err(ExprParseError::ExpectedToken { stack });
-                    };
-                    stack.push(Monadic(f, x.into()));
-                }
-                Ok(ExprFunction::Dyadic(f)) => {
-                    let Some(x) = stack.pop() else {
-                        return Err(ExprParseError::ExpectedToken { stack });
-                    };
-                    let Some(y) = stack.pop() else {
-                        return Err(ExprParseError::ExpectedToken { stack });
-                    };
-                    stack.push(Dyadic(f, x.into(), y.into()));
-                }
-                Err(()) => {
-                    return Err(ExprParseError::UnknownToken {
-                        token: token.to_owned(),
-                        stack,
-                    })
-                }
-            }
-        }
-        stack.pop().ok_or(ExprParseError::ExpectedToken { stack })
-    }
-}