ExternalOperation

ExternalOperation["Eval","code"] represents an external evaluation of "code".

ExternalOperation["Eval","code",assoc] represents an external evaluation of "code" with parameters given by assoc.

ExternalOperation["Call",func,arg1,arg2,…] calls the function func with the given arguments arg1, arg2, ….

ExternalOperation["GetAttribute",obj,"attr"] gets the attribute "attr" of obj.

ExternalOperation["SetAttribute",obj,"attr",val] sets the attribute "attr" of obj to the given value val.

ExternalOperation["Cast",obj,"type"] casts obj to the given "type".

ExternalOperation["op", arg1,arg2,…] represents the external operation named "op" using arguments arg1, arg2, ….

Please visit the official Wolfram Language Reference for more details and examples on core symbols.