Allow method access on non-structs

[palmdalian]

I was trying to do an expression with a uuid .String() method, but reflect shows that as an array instead of struct.

All of the tests pass and my use case seems to work now...so I think we're good?

[palmdalian]

Hello,

Have you seen https://github.com/antonmedv/expr? 😃

@antonmedv I hadn't! Nice project. The reason why we forked govaluate is that we needed two use cases:

1. To reduce expressions using the environment map and leave variables in place that aren't in that map.
2. Output and translate that reduced expression back out to a string that we send to the client for them to evaluate on device with a java library (https://github.com/uklimaschewski/EvalEx)

I didn't see that as an option for your library, but the Reduce function is pretty nice if you're looking for new features to add 😃

[antonmedv]

Can you tell me more about this reduce function more? 😀

[palmdalian]

Can you tell me more about this reduce function more? 😀

Sure! You can see the tests should give a decent idea: https://github.com/tonalfitness/govaluate/blob/master/reduce_test.go
The basic idea is that you pass in a set of known values and it does variable replacement or partial evaluation of any nodes that can be simplified.

The other part is Print.go that lets you override literals to conform with other libraries.
https://github.com/tonalfitness/govaluate/blob/master/print_test.go
Not sure if that case is as common, but govaluate had something similar for outputting as as sql string.

[antonmedv]

Expr has something similar to reduce: constant folding
But this functionality unexported and used during compile step.

Print to SQL not supported, yeah.