Concatenation of builtin functions(sincos(x)) is valid.

[alexandrustana]

The following expression sincos(1) is seen as valid for exp4j
Although the evaluation of the expression is done correct, meaning, even if the expression is written in the following manner sincos(1) the code evaluates it as sin(cos(1)), shouldn't the shunting yard algorithm detect that sincos(x) function is not written in a valid form and when calling the validate() method return false?

[fasseg]

Hey @alexinul, Thanks for submitting this issue. This is a bug probably due to the implicit multiplication feature.