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TheCommon Expression Language (CEL) is a non-Turing complete language designedfor simplicity, speed, safety, andportability. CEL's C-like syntax looks nearly identical to equivalent expressions in C++, Go, Java, and TypeScript. CELis ideal for lightweight expression evaluation when a fully sandboxed scripting language is too resource intensive.

// Check whether a resource name starts with a group name.resource.name.startsWith("/groups/" +auth.claims.group)

// Determine whether the request is in the permitted time window.request.time-resource.age<duration("24h")

// Check whether all resource names in a list match a given filter.auth.claims.email_verified&&resources.all(r,r.startsWith(auth.claims.email))

This project includes a CEL-parser and an interpreter which means that it can be used to evaluate CEL-expressions. Thelibrary aims to be very simple to use, while still being fast, safe, and customizable.

fnmain(){let program =Program::compile("add(2, 3) == 5").unwrap();letmut context =Context::default();    context.add_function("add", |a:i64,b:i64| a + b);let value = program.execute(&context).unwrap();assert_eq!(value,true.into());}

Check out these other examples to learn how to use this library:

• Simple - A simple example of how to use the library.
• Variables - Passing variables and using them in your program.
• Functions - Defining and using custom functions in your program.
• Concurrent Execution - Executing the same program concurrently.