OpenEuphoria

Re: string_exec()

• Posted by petelomax Mar 01, 2015
• 2325 views

That certainly makes life easier, but I suspect the requirement to obtain/set stuff in the host will turn up soon enough.

-- compile code into a context 
{aContext, resultCode} = compile_code("myfile.ex") 
 
-- set top-level value for variable "some_string" to "a_value" 
{aContext, resultCode} = set_value(aContext, "some_string", "a value") 
 
-- execute procedure in context 
{aContext, resultCode} = call_routine(aContext, "some_procedure", {1,2,3}) 
 
-- execute function in context 
{aContext, returnValue, resultCode} = call_routine(aContext, "some_function", {1,2,3}) 
 
-- create an empty context that code can be compiled to 
sequence newContext = create_context() 
 
-- compile code into the context 
{newContext, resultCode} = compile(newContext, "integer a\na=22") 
 
-- retrieve top-level "a" value from the context 
{result, resultCode} = get_value(newContext, "a") 

I was thinking that set_value and get_value might not be as powerful and flexible as simple assignments/return expressions. How about this, to achieve the same result:

ctrl = string_exec(NULL,"include myfile.ex\n"& 
                        "some_string = \"a_value\"\n"& 
                        "some_procedure(1,2,3)\n"& 
                        "return some_function(1,2,3)") 
returnValue = ctrl[RESULT] 
 
newContext = string_exec(NULL,"integer a\na=22\nreturn a") 
result = newContext[RESULT] 

or, also equally:

ctrl = string_exec(NULL,"include myfile.ex") 
ctrl = string_exec(ctrl,"some_string = \"a_value\"") 
ctrl = string_exec(ctrl,"some_procedure(1,2,3)") 
{context,returnValue,errors} = string_exec(ctrl,"return some_function(1,2,3)") 
 
newContext = string_exec(NULL,"integer a") 
newContext = string_exec(newContext,"a=22") 
{newContext,result,errors} = string_exec(newContext,"return a") 

Sure. I've no problem with or real preference for either ctrl = string_exec() and retrieving by index, or {context,value,error} = string_exec() at this stage¹.
It also strikes me that a simple (integer) error is unlikely to be sufficient, instead {code snippet,line/col,human-readable message,...}, not unlike what we get in an ex.err.
Oh, yes, I see what you were asking now, the context/ctrl is it - everything you could ever possibly need must be available somewhere within it. Details tba.

Pete

¹ Random petty detail: by defining context[1] to be a specific integer, say #0C057347, string_exec() could easily cope with getting context or {context,value,error} passed back to it. In other words, in a loop, both ctrl=string_exec(ctrl,s) and {context,value,error}=string_exec(context,s) would be fine. Right now the latter looks better, but needing to throw these things about might tip things in favour of the former.