lerox: Add lerox, a silly little combinator library

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["libconlang"]
+members = ["libconlang", "lerox"]
 resolver = "2"
 
 [workspace.package]

lerox/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "lerox"
+authors.workspace = true
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

lerox/src/lib.rs

@@ -0,0 +1,53 @@
+//! Lerox is a stupid, simple combinator library, part of the Conlang project
+
+pub trait Combinable {
+    /// Evaluates the [Combinable], and returns whether it is alright
+    fn is_alright(&self) -> bool;
+    /// Makes this [Combinable] alright, somehow
+    fn alright(self) -> Self;
+}
+
+pub trait Combinator: Combinable + Sized {
+    /// If self is alright, runs f(self)
+    fn and(self, f: impl Fn(Self) -> Self) -> Self {
+        match self.is_alright() {
+            true => f(self),
+            false => self,
+        }
+    }
+
+    /// If self is not alright, runs f(self)
+    fn or(self, f: impl FnOnce(Self) -> Self) -> Self {
+        match self.is_alright() {
+            true => self,
+            false => f(self),
+        }
+    }
+
+    /// Returns the result of running f on self, or if it fails, the original self
+    fn and_maybe(self, f: impl Fn(Self) -> Self) -> Self
+    where Self: Clone {
+        self.clone().and(f).or(|_| self)
+    }
+
+    /// Returns the result of running f on self, or if it fails, runs g on self
+    fn and_either(self, f: impl Fn(Self) -> Self, g: impl Fn(Self) -> Self) -> Self
+    where Self: Clone {
+        self.clone().and(f).or(|_| g(self))
+    }
+
+    /// Repeats the function f on self until it fails
+    fn and_any(mut self, f: impl Fn(Self) -> Self) -> Self {
+        while self.is_alright() {
+            self = self.and(&f)
+        }
+        self.alright()
+    }
+
+    /// Repeats the function f on self at least once, then until it fails.
+    fn and_many(self, f: impl Fn(Self) -> Self) -> Self {
+        self.and(&f).and_any(f)
+    }
+}
+
+impl<C: Combinable> Combinator for C {}

libconlang/Cargo.toml

@@ -1,9 +1,11 @@
 [package]
 name = "conlang"
+authors.workspace = true
 version.workspace = true
 edition.workspace = true
-authors.workspace = true
+license.workspace = true
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lerox ={ path = "../lerox" }