superisaac / FEEL.go

An interpreter of the FEEL language(Friendly Enough Expression Language) in go

FEEL.go

The interpreter of the FEEL language(Friendly Enough Expression Language) in go, FEEL is broadly used in DMN and BPMN to provide rule engine and script support, the FEEL.go module can be imported into other go projects or used as command line executable as FEEL interpreter.

Build

• run make build to build feel interpreter bin/feel
• run make test to run testing

Examples

% bin/feel -c '"hello " + "world"'
"hello world"

% bin/feel -c '(function(a, b) a + b)(5, 8)'
13

# dump AST tree instead of evaluating the script
% bin/feel -c 'bind("a", 5); if a > 3 then "larger" else "smaller"' -ast
(explist (call bind ["a", 5]) (if (> a 3) "larger"  "smaller"))

% bin/feel -c 'some x in [3, 4, 8, 9] satisfies x % 2 = 0'
4

% bin/feel -c 'every x in [3, 4, 8, 9] satisfies x % 2 = 0'
[
  4,
  8
]

for more examples please refer to testing

Use in golang codes

import (
  feel "github.com/superisaac/FEEL.go"
)

res, err := feel.EvalString(input)