Code::Completion Rewrite

From Code::Blocks

Background

The current Code::Completion plug-in has some flaws, and is currently development frozen. The current plug-in lacks full support for:

  1. function and class templates
  2. default arguments in some cases
  3. some of the more complicated c++ mucky business

Current Effort

Structure

The current C::C is a monolithic library of features, which could be de-coupled and split up for use in multiple plugins, providing extra functionality and flexibility in the future. Therefore, I propose the C::C be broken up into the following components:

  • Code::SymbolTable
    • Provide a list of valid symbols in the workspace, along with relevant scope information
  • Code::Completion
    • Provide Auto-complete features
  • Code::SymbolOutline
    • Provide Symbol browser, find symbol, function jump features
  • Code::Refactoring
    • Provide code refactoring features
  • Code::Documentation
    • Provide automatic code generation features

Purpose Statement

Code::Completion

The current Code::Completion plugin is outdated, and needs a complete rewrite. The purpose of the Code::Completion plugin is thus:

  • Provide a list of likely symbols in the current scope as possible solutions to the current symbol.
  • Provide function tooltips
    • Parameter list
    • Relevant documentation
  • Provide completion features for class constructors
  • Provide completion features for initializer lists

Process

Code::SymbolTable

class symbol
{
    string name;              // name of the symbol
    int    id;                // Id of the symbol, should be unique in the project
    int    file_id;           // if od file where the symbol has been declared
    int    filepos_begin;     // Position where declaration of the symbol starts
    int    filepos_end;       // Position where declaration of the symbol ends
    int    type;              // Type of the symbol: macro / class / typedef / variable / function
    int    modifiers;         // Bitfield used to mark some estra properties of symbol like that it is static or inline
    int    value_type_id;     // Id of symbol which represents c++ type of current symbol (like type of variable or type of returned value from function)
    int    extra_type_id;     // Extra type used in some cases
    list   children;          // List of child elements of this symbol (members in class etc)
    list   extra_lists[3];    // Some extra lists which can provide additional symbols depending on type of current
                              // symbol - like list of base classes or list of template arguments, maybe we could give
                              // more than 3 lists, but I didn't found any reason for that now.
    map    extra_values;      // int -> string map which can keep some extra data
}

Code::Completion

  1. Generate a list of all valid symbols in the current scope
    1. Take global list from C::SymbolTable
    2. Add in local scope parsed on the fly
  2. Reduce that list to what is likely
  3. Show that list to the user in some fashion
  4. Insert the proper solution on user request

More complex cases of C::C usage

Here we can put some more complex examples of c++ code where C::C may fail. Symbols that may be hard to find should be marked in bold

1: Fetching type of operator call

#include <string>
using namespace std;

int main(int,char**)
{
    ( string("first") + "second" + "third" ) . c_str();
    return 0;
}

2: Template classes

template<typename T> class Template
{
public:
    T& GetInstance() { return m_Instance; }
private:
    T m_Instance;
};

class Parameter
{
public:
    void PrintfText() { printf("Text"); }
};

int main(int,char**)
{
    Template<Parameter> Object;
    Object.GetInstance().PrintfText();
}