interpreter

Ok, so I'm running some loops to process data stored in list objects. Ever mindful of the infamous fortune admonishment not to use eval(parse(mystring)) , I came up with this: Rgames> bar $foo $foo$fast [1] 1 2 3 4 5 $foo$slow [1] 6 7 8 9 10 $oof $oof[[1]] [1] 6 7 8 9 10 $oof[[2]] [1] 1 2 3 4 5 Rgames> rab<-'bar' Rgames> do.call('$',list(as.name(rab),'oof')) [[1]] [1] 6 7 8 9 10 [[2]] [1] 1 2 3 4 5 Typically I'd be selecting a list (of which bar is one such) and then one element of the list (e.g. oof ) which contains my data. The code above does the same thing as eval(parse(text=paste(rab,'$',

What tips can you give a person who is looking to write a programming or script language? I am not worried about how to program nor design a compiler but how to develop one quickly using tools and code generators. Last time i tried i coded it in c++ and the states and syntax took almost as long as writing the actual logic. I know the follow tools would help. I was thinking i could generate c++ code and have gcc compile that. Using the tools above how long would you estimate it would take to write a program or script language? Variations on this question have been asked repeatedly, as far back

I have some Scala functions defined in a file, not in a class, and I would like to use them in the Scala interpreter. I know I can say scala filename.scala to simply run the file and exit the interpreter, but I would like to run the file and then stay in the interpreter so I can do some testing. Can anyone tell me how to simply load a file into the interpreter so I can use the functions defined within it? type :load /path/to/file in Scala REPL. You can get complete list of available commands by typing :help Suresh Babu On occasions, :paste might be your better friend (than :load ). Here is an

I'm trying to understand the python compiler/interpreter process more clearly. Unfortunately, I have not taken a class in interpreters nor have I read much about them. Basically, what I understand right now is that Python code from .py files is first compiled into python bytecode (which i assume are the .pyc files i see occasionally?). Next, the bytecode is compiled into machine code, a language the processor actually understands. Pretty much, I've read this thread Why python compile the source to bytecode before interpreting? Could somebody give me a good explanation of the whole process

I am asking this because I use Python, but it could apply to other interpreted languages as well (Ruby, PHP, JavaScript). Am I slowing down the interpreter whenever I leave a comment in my code? According to my limited understanding of an interpreter, it reads program expressions in as strings and then converts those strings into code. It seems that every time it parses a comment, that is wasted time. Is this the case? Is there some convention for comments in interpreted languages, or is the effect negligible? For the case of Python, source files are compiled before being executed (the .pyc