std::vector<std::string> Causes Segfault

Download links aren't working for me.

Crap :/ I'll fix those.

Edit: Fixed

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Is there no main?

cire (8284)

As naraku9333 pointed out, there doesn't seem to be a main in your functions.

May I ask why you always pass vectors by value?

It looks like it would be very easy in Script::runEquation to access outside of the vector.

Value::val is only assigned a value in Value::operator= (and the defaulted copy constructor,) meaning it's actual value will be unspecified everywhere. I have to assume it's inclusion in Value::nonZero will lead to incorrect results.

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Line 63 in Script Interpreter.cpp could be the issue.

Edit: Yeah, remove the semicolon on 63.

Also, your readFile function wouldn't work for me in VS2013 so I used this

string Script::readFile(string file)
{
    //TODO - read from directory of script file, then from other search directories if not there
    ifstream input(file, ios::binary);
    string data;
    copy(istream_iterator<char>(input), istream_iterator<char>(), back_inserter(data));
    
    return data;
}

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Script Interpreter.cpp: In member function ‘Value Script::runFunction(std::string, std::vector<Value>)’:
Script Interpreter.cpp:672:1: warning: control reaches end of non-void function [-Wreturn-type]

> Line 63 in Script Interpreter.cpp could be the issue.
> Edit: Yeah, remove the semicolon on 63.

//original
for (; data[i]!='\n'; i++);
i--;

//with `the' semicolon removed
for (; data[i]!='\n'; i++)
   i--; //infinite loop

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@Cire: I do have a main function, perhaps I forgot to zip main.cpp, I'll retype it below (I'm at school right now). I suppose I could convert to references, I just wasn't thinking of it when I wrote all the code, I was just trying to get all of the design down before I forgot it. Also, thanks for pointing out the problem with Value::val, it was a last minute addition I made but never really thought through. As for reading past the end(s) of the vectors, the interpreter somewhat assumes syntactical correctness of the script it's running. I figured since it was only for my personal use it wasn't a huge deal, although it's still a good idea to put checks in all of my loops.

@ne555: I like your readFile function better :) Line 63 just "reads" through the script data, ignoring characters until it reaches '\n' (this is for line comments). The semi colon is supposed to be there. The i--; afterwards is to essentially cancel the effect of the i++ in the for loop to ensure that all characters are read.

main.cpp

#include "Script Interpreter.hpp"
#include <iostream>
using namespace std;

int main()
{
    string file;
    cout << "File: ";
    getline(cin, file);

    Script scr(file);
    try
    {
        scr.run();
    }
    catch (runtime_error err)
    {
        cout << err.what << endl;
    }

    return 0;
}

This may or may not be correct, but that's the jist of it. I don't have access to my files or environment at the moment. I'll definitely make your guys' recommended changes when I get home and I'll update this thread then.

@ne555
You're absolutely correct. Taking out the semicolon appeared to fix an issue I created with the change in readFile, the istream_iterator doesn't seem to be extracting newline chars from the stream which was causing the for loop to crash.

bool Script::isFunction(string name)
{
    return (functions.find(name)!=functions.end() && ( name=="print" || name=="pause")); //TODO - add other function names here
}

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¿what's the point of the `functions' map then?

The functions map is for user defined functions, and the other checks are going to be for functions that I hard code right into the interpreter.

After making the recommended changes, the original problem still persists. In GDB under Windows the segmentation fault occurs in Value::operator= on the line where the std::string data member is copied. I'll play with it more in the next few days, I'm just too tired to think right now. I feel like it's going to end up being something that's stupidly simple, or that I'll just never figure it out.

With only changes to Value.hpp

Value()
    {
        val = 0;
        data = "";
        type = None;
    }

and Script Interpreter.cpp here

string Script::readFile(string file)
{
    //TODO - read from directory of script file, then from other search directories if not there
    ifstream input(file, ios::binary);
    string data, tmp;
    
    while(getline(input, tmp))
    {
        data += tmp + "\n";
    }
    return data;
}

and here

bool Script::isFunction(string name)
{
    return (functions.find(name)!=functions.end() && name=="print" || name=="pause"); //TODO - add other function names here
}

It runs with no exceptions for me in VS2013 and MinGW-4.8.1, also ran through GDB with no issues.
Output:

Data type: int
Function: function
Start args
Data type: int
Variable: arg1
Next arg
Data type: string
Variable: arg2
Next arg
Data type: int
Variable: const
End args
Start block
Data type: int
Variable: tmp
Operator: =
Variable: arg1
Operator: +
Variable: const
End statement
Function: print
Start args
Variable: arg2
End args
End statement
Return
Variable: tmp
End statement
End block
Data type: int
Variable: var
Operator: =
Int constant: 5
End statement
Data type: string
Variable: str
Operator: =
String constant: dog
End statement
JumpPoint: beg
Function: print
Start args
String constant: Beg

End args
End statement
Function: pause
Start args
End args
End statement
Variable: var
Operator: =
Operator: (
Variable: var
Operator: +
Int constant: 5
End args
Operator: *
Int constant: 2
Operator: -
Int constant: 90
Operator: /
Int constant: 3
End statement
Function: print
Start args
String constant: Var =
Next arg
Variable: var
Next arg
String constant:

End args
End statement
Conditional
Start args
Variable: var
Operator: <
Int constant: 15
End args
Start block
Variable: str
Operator: =
Variable: str
Operator: +
String constant: gy
End statement
End block
Conditional
Start args
Variable: str
Operator: ==
String constant: doggy
End args
Variable: var
Operator: =
Variable: var
Operator: -
Int constant: 15
End statement
Function: print
Start args
String constant: Var =
Next arg
Variable: var
Next arg
String constant:

End args
End statement
Loop
Start args
Variable: var
Operator: <=
Int constant: 5
End args
Start block
Variable: var
Operator: =
Variable: var
Operator: +
Int constant: 1
End statement
Function: print
Start args
String constant: Var =
Next arg
Variable: var
Next arg
String constant:

End args
End statement
End block
Function: print
Start args
Function: function
Start args
Variable: var
Next arg
Variable: str
Next arg
Int constant: 78
End args
End args
End statement
Goto: beg
End statement
Run tokens
Undefined function: print

> Undefined function: print
but that's one of the hard-coded functions.
According to the description in http://www.cplusplus.com/forum/general/121435/#msg661436 the original `Script::isFunction(string name)' was correct (it could be better implemented thought)

@ModShop: ¿what are you waiting to upload the updated code?
http://www.cplusplus.com/forum/general/112111/

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@naraku9333: I added the default constructor to Value, as well as modified the readFile function, but I still get the segfault. I believe you don't get it because the program throws and exception because isFunction() will always return false in your version.

@ne555: Sorry, I haven't been on my computer much at all this weekend. Here is the updated code: http://www.filedropper.com/scriptinterpreter

EDIT: I changed the evaluate() function and runTokens() function to take references rather than values, but it made no difference. Is it at all possible that somehow std::vector is calling the same destructors twice?

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You've got an invalid string object whose internal buffer points to garbage. So when its destructor is invoked you've got a bad delete.

That invalid object is constructed in the `Script::runFunction()' method, as you promise to return a `Value' but didn't do it (look at the path `TODO - hard code functions here')
That's why it says `warning: control reaches end of non-void function'