diggs/go-eval

An eval function for Go that supports boolean and arithmetic expressions

What is go-eval?

go-eval evaluates boolean or basic arithmetic expressions from strings. It's analogous to a basic form of the eval function often found in dynamic languages.

Examples:

res, err := EvalBool("1 > 2")
log.Print(res)
> false

res, err := EvalBool(`(1 + 3) >= 4 && ("FOO" == "BAR" || "FOO" == "FOO")`)
log.Print(res)
> true

res, err := EvalArithmetic("1 + 2")
log.Print(res)
> 3

res, err := EvalArithmetic("2 - -1")
log.Print(res)
> 3

How does it work?

go-eval leverges the awesome AST and Parser packages that ship in the Go standard library. It constructs an abstract syntax tree from the specified expression and walks the tree to determine the result.

Tests

go get github.com/tools/godep
godep restore
go test

PASS
ok  	github.com/diggs/go-eval	0.005s

Limitations

Floats are not supported yet. Only boolean and arithmetic expressions are supported, this doesn't support conditionals etc.