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The Common Expression Language (CEL) is a non-Turing complete language designed for simplicity, speed, safety, and portability. CEL's C-like syntax looks nearly identical to equivalent expressions in C++, Go, Java, and TypeScript. A CEL "program" is a single expression. The examples have been tagged as java, go, and typescript within the markdown to showcase the commonality of the syntax. CEL is ideal for lightweight expression evaluation when a fully sandboxed scripting language is too resource intensive. To get started, try the Codelab. Determine the variables and functions you want to provide to CEL. Parse and check an expression to make sure it's valid. Then evaluate the output AST against some input. Checking is optional but strongly encouraged. The parsing phase indicates whether the expression is syntactically valid and expands any macros present within the environment. Parsing and checking are more computationally expensive than evaluation.
Features
- Parse and Check
- Macros are optional but enabled by default
- Evaluate for fun and profit
- To improve the odds of successful evaluation with partial state, CEL uses commutative logical operators &&, ||
- Parse and check errors have friendly error messages with pointers to where the issues occur in source
- Both the parsed and checked expressions contain source position information about each node that appears in the output AST
Project Samples
