From c7c48f94c5e582fc596a3797ca5fdaad7a6c6a58 Mon Sep 17 00:00:00 2001
From: Clark McCauley <clarkmccauley@gmail.com>
Date: Mon, 29 May 2023 12:15:47 -0600
Subject: [PATCH] Added some examples about how to use the library

---
 Cargo.toml               |  2 +-
 README.md                |  8 ++++++++
 example/Cargo.toml       | 21 +++++++++++++++++++++
 example/src/functions.rs | 19 +++++++++++++++++++
 example/src/simple.rs    |  8 ++++++++
 example/src/variables.rs | 10 ++++++++++
 interpreter/src/lib.rs   |  6 +++---
 7 files changed, 70 insertions(+), 4 deletions(-)
 create mode 100644 example/Cargo.toml
 create mode 100644 example/src/functions.rs
 create mode 100644 example/src/simple.rs
 create mode 100644 example/src/variables.rs

diff --git a/Cargo.toml b/Cargo.toml
index 00b8f8c..66ee733 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,5 @@
 [workspace]
-members = ["cli", "parser", "interpreter"]
+members = ["cli", "parser", "interpreter", "example"]
 
 [profile.bench]
 lto = true
diff --git a/README.md b/README.md
index 68e875f..fe293ec 100644
--- a/README.md
+++ b/README.md
@@ -34,3 +34,11 @@ fn main() {
     assert_eq!(value, true.into());
 }
 ```
+
+### Examples
+
+Check out these other examples to learn how to use this library:
+
+- [Simple](./example/src/simple.rs) - A simple example of how to use the library.
+- [Variables](./example/src/variables.rs) - Passing variables and using them in your program.
+- [Functions](./example/src/functions.rs) - Defining and using custom functions in your program.
\ No newline at end of file
diff --git a/example/Cargo.toml b/example/Cargo.toml
new file mode 100644
index 0000000..0dfbf17
--- /dev/null
+++ b/example/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "example"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+cel-interpreter = { path = "../interpreter" }
+
+[[bin]]
+name = "simple"
+path = "src/simple.rs"
+
+[[bin]]
+name = "variables"
+path = "src/variables.rs"
+
+[[bin]]
+name = "functions"
+path = "src/functions.rs"
\ No newline at end of file
diff --git a/example/src/functions.rs b/example/src/functions.rs
new file mode 100644
index 0000000..55b31b8
--- /dev/null
+++ b/example/src/functions.rs
@@ -0,0 +1,19 @@
+use cel_interpreter::{CelType, Context, Expression, Program, ResolveResult};
+
+fn main() {
+    let program = Program::compile("add(2, 3)").unwrap();
+    let mut context = Context::default();
+    context.add_function("add", add);
+
+    let value = program.execute(&context).unwrap();
+    assert_eq!(value, 5.into());
+}
+
+/// The add function takes two arguments and returns their sum. We discard the first
+/// parameter because the add function is not a method, it is always called with two
+/// arguments.
+fn add(_: Option<&CelType>, args: &[Expression], ctx: &Context) -> ResolveResult {
+    let a = CelType::resolve(args.get(0).unwrap(), ctx)?;
+    let b = CelType::resolve(args.get(1).unwrap(), ctx)?;
+    Ok(a + b)
+}
diff --git a/example/src/simple.rs b/example/src/simple.rs
new file mode 100644
index 0000000..1dae526
--- /dev/null
+++ b/example/src/simple.rs
@@ -0,0 +1,8 @@
+use cel_interpreter::{Context, Program};
+
+fn main() {
+    let program = Program::compile("1 == 1").unwrap();
+    let context = Context::default();
+    let value = program.execute(&context).unwrap();
+    assert_eq!(value, true.into());
+}
diff --git a/example/src/variables.rs b/example/src/variables.rs
new file mode 100644
index 0000000..76f1f6e
--- /dev/null
+++ b/example/src/variables.rs
@@ -0,0 +1,10 @@
+use cel_interpreter::{Context, Program};
+
+fn main() {
+    let program = Program::compile("foo * 2").unwrap();
+    let mut context = Context::default();
+    context.add_variable("foo", 10);
+
+    let value = program.execute(&context).unwrap();
+    assert_eq!(value, 20.into());
+}
diff --git a/interpreter/src/lib.rs b/interpreter/src/lib.rs
index 8cec926..51beff0 100644
--- a/interpreter/src/lib.rs
+++ b/interpreter/src/lib.rs
@@ -1,14 +1,14 @@
 extern crate core;
 
-use crate::context::Context;
-use crate::objects::{CelType, ResolveResult};
-use cel_parser::ast::Expression;
 use cel_parser::parser::ExpressionParser;
 use std::convert::TryFrom;
 use std::rc::Rc;
 use thiserror::Error;
 
 pub mod context;
+pub use cel_parser::Expression;
+pub use context::Context;
+pub use objects::{CelType, ResolveResult};
 mod duration;
 mod functions;
 pub mod objects;