Context Class

Brief: represents the context of evaluation of an expression

Detailed description

This class represents the context of Engine::eval().

The default constructor constructs a null context (see isNull()). Calling any other function than isNull() on a null context is undefined behavior.

Use addVar() to add variables to the context and clear() to remove to clear the context.

Use exists() to test for the existence of a variable and get() to retrieve the value of a variable.

Members documentation

int id() const

Brief: returns whether the context id

This function returns -1 if the context isNull().

bool isNull() const

Brief: returns whether the context is null

Engine* engine() const

Brief: returns the context’s engine

const std::string& name() const

Brief: returns the context name

void setName(const std::string& name)

Brief: sets the context name

const std::map<std::string, Value>& vars() const

Brief: returns the variables of the context

void addVar(const std::string& name, const Value& val)

Brief: add a variable to the context

bool exists(const std::string& name)

Brief: returns whether a variable with a given name exists in the context

Value get(const std::string& name) const

Brief: retrieves a value by its name

void use(const Module& m)

Brief: makes the symbols of a module available in the context

void use(const Script& s)

Brief: makes the symbols of a script available in the context

Scope scope() const

Brief: returns the context’s scope

This scope is used to resolve names within the expression passed to Engine::eval().

void clear()

Brief: clears the context