Thread: Accurately detecting function calls

I have a small problem in a little project I'm doing that attempts to accurately detect function calls (not definitions) in an editor window. I only have access to the lines of text in the editor (Eg. Editor->GetLineText()) so I've wrote a few routines for tokenising the line, removing newlines, and concatenating until I receive a semicolon just in case a call goes over a single line.

Now I need an accurate way of detecting what is a function call. I don't want to use a full lexical analyser, as it seems overkill, and I've no interest in understanding what the written code does, don't care about casts, etc.

I was thinking of the following: A non-reserved name followed immediately by an opening bracket is a function call with the name being the name of the function. This should exclude stuff like "for(" "switch(" and "if(" for example, but I'm concerned that it'll fall over with function pointers:

float (*GetPtr1(const char opCode))(float, float)

Maybe If I check for the asterix before the name, it'll cure that.

Any suggestions?

Oh, and I'm posting this here because I don't care about parsing C++ code. So no need to worry about namespaces or classes. All code is standard ansi-compliant C code (apart from the parser itself, which is all C++).

The other thing to watch for is prototypes and definitions I guess. Perhaps looking for types inside the parens, or a type immediately before then name?

Sounds reasonable: "A non-reserved name followed immediately by an opening bracket is a function call with the name being the name of the function"

Don't forget "sizeof" which is often followed by a bracket although it doesn't need to be.
Even function pointers, when called, follow the same syntax. There wouldn't be an asterisk before the name as in your example. You've shown the prototype which shouldn't be detected anyhow.

You need to worry about detecting function calls vs. prototype or function definitions.

Originally Posted by nonoob

Even function pointers, when called, follow the same syntax. There wouldn't be an asterisk before the name as in your example. You've shown the prototype which shouldn't be detected anyhow.

I can detect the fact the cursor is inside a function by looking for a closing bracket followed immediately by an opening brace in the token list. Assuming I'm correct in thinking that function prototypes and definitions can not happen inside a function, that just leaves me with the definition of function pointer which can happen, as they are really just 'normal' variables. "float (" would be recognised as a reserved name, but "user_defined_type (" would be recognised as a function call, unless I parse the entire file (including #includes) looking for and storing all typedef's. That seems way overboard.

I think the best thing to do is quickly scan the file for all function calls (should be easy enough) and then change the algorithm from "non-reserved word" to "known function name".